Coyote Blog

OK, I lied.  I have one more post I want to make on global warming now that Steve McIntyre's site is back up.  I suspect I tend to bury the lede in my warming posts, because I try to be really careful to set up the conclusion in a fact-based way.  However, for this post, I will try a different approach.  Steven McIntyre has reshuffled the data in a study on urbanization and temperature that is relied on by the last IPCC report to get this chart for US Temperature data.

Conclusion?  For this particular set of US temperature data, all the 20th century warming was observed in urban areas, and none was observed in rural areas less affected by urban heat islands, asphalt, cars, air conditioning, etc.

If it can be generalized, this is an amazing conclusion -- it would imply that the sum of US measured warming over the last century could be almost 100% attributed to urban heat islands (a different and more localized effect than CO2 greenhouse gas warming).  Perhaps more importantly, outside of the US nearly all of the historical temperature measurement is in urban areas -- no one has 100 year temperature records for the Chinese countryside.  However much this effect might be over-stating US temperature increases, it would probably be even more pronounced in measurements in other parts of the word.

OK, so how did he get this chart?  Did he cherry-pick the data?  First, a bit of background.

The 2003 Peterson study on urban effects on temperature was adopted as a key study for the last IPCC climate report.  In that report, Peterson concluded:

Contrary to generally accepted wisdom, no statistically significant
impact of urbanization could be found in annual temperatures.

This study (which runs counter to both common sense and the preponderance of past studies) was latched onto by the IPCC to allow them to ignore urban heat island effects on historical temperatures and claim that most all past warming in the last half-century was due to CO2.  Peterson's methodology was to take a list of several hundred US temperature stations (how he picked these is unclear, they are a mix of USHCN and non-USHCN sites) and divide them between "urban" and "rural" using various inputs, including satellite photos of night lights.  Then he compared the temperature changes over the last century for the two groups, and declared them substantially identical.

However, McIntyre found a number of problems with his analysis.  First, looking at Peterson's data set, he saw that the raw temperature measurement did show an urbanization effect of about 0.7C over the last century, a very large number.  It turns out that Peterson never showed these raw numbers in his study, only the numbers after he applied layers of "corrections" to them, many of which appear to McIntyre to be statistically dubious.  I discussed the weakness of this whole "adjustment" issue here.

Further, though, McIntyre found obviously rural sites lurking in the urban data, and vice versa, such that Peterson was really comparing a mixed bag with a mixed bag.  For example, Snoqualmie Falls showed as urban -- I have been to Snoqualmie Falls several times, and while it is fairly close to Seattle, it is not urban.  So McIntyre did a simple sort.  He took from Peterson's urban data set only large cities, which he defined as having a major league sports franchise  (yes, a bit arbitrary, but not bad).  He then compared this narrower urban data set from Peterson against Peterson's rural set and got the chart above.  The chart is entirely from Peterson's data set, with no cherry-picking except to clean up the urban list.

Postscript:  Please don't get carried away.  Satellite measurement of the troposphere, which are fairly immune to these urbanization effects, show the world has been warming, though far less than the amount shown in surface temperature databases.

Update: To reinforce the point about global sites, Brazil apparently only has six (6) sites in the worldwide database.  That is about 1/200 of the number of sites in the continental US, which has about the same land area.  And of those six, McIntyre compares urban vs. rural sites.  Guess what he finds?  And, as a follow up from the postscript, while satellites show the Northern Hemisphere is warming, it shows that the Southern Hemisphere is not.

We all know why Newsweek and many others (like Kevin Drum) choose to use the term "denier" for those of us who are skeptical of catastrophic anthropogenic global warming:  These media folks, who are hesitant to use the word "terrorist" because of its emotional content, want to imply that we skeptics are somehow similar to Holocaust deniers.

But beyond just the issues of false emotional content, the word denier is incorrect as applied to most skeptics, including myself, and helps man-made warming hawks avoid a difficult argument.  I try to be careful to say that I am a skeptic of "catastrophic man-made (or anthropogenic) global warming theory." 

• So, does that mean I think the world is not warming?  In fact, the evidence is pretty clear that it is warming (though perhaps not by as much as shown in current surface temperature databases).
• So does this mean that I think that human activities are not causing some warming?  In fact, I do think man-made CO2 is causing some, but not all the current 20th century warming trend.  I also think that man's land use  (urbanization, irrigated agriculture, etc) has effects on climate.

Where I really get skeptical is the next proposition -- that man's burning of fossil fuels is going to cause warming in the next century that will carry catastrophic impacts, and that these negative effects will justify massive current spending and government interventions (that will have their own negative consequences in terms of lost economic growth, increased poverty, and reduction in freedoms). 

Strong supporters of catastrophic man-made global warming theory do not usually want to argue this last point.  It is much easier to argue points 1 and 2, because the science is pretty good that the earth has warmed (though the magnitude is in question) and that CO2 greenhouse effect does cause warming (though the magnitude is in question).  That is why skeptics are called deniers.  It is in effect a straw man that allows greenhouse supporters to stay on 1 and 2 without getting into the real meat of the question.

Here is a quick example to prove my point.  Follow me for three paragraphs, then ask yourself if you have ever heard any of this in the media or on any RealClimate-type site's FAQ.

Anthropogenic global warming hawks admit that the warming solely from the CO2 greenhouse effect will likely NOT rise to catastrophic levels.  So how do they get such big, scary forecasts?  The answer is positive feedback.

Almost every process you can think of in nature operates by negative
feedback, meaning that an input to a system is damped.  Roll a ball, and eventually friction and wind resistance
bring
it to a stop.    Positive feedback means that an input to the system is multiplied and increased.  Negative feedback is a ball in the bottom of a bowl, always returning to the center; positive feedback is a ball perched precariously at the top of a
mountain that will run faster and faster downhill with a tiny push. Positive feedback
breeds instability, and processes that operate by positive feedback are
dangerous, and usually end up in extreme states -- these processes tend
to
"run away" like the ball rolling down the hill.  Nuclear fission, for
example, is a positive feedback process. 

Current catastrophic man-made global warming theory asserts that our climate is dominated
by positive feedback.  The last UN IPCC report posits that a small increase in
temperature from CO2 is multiplied 2,3,4 times or more by positive
feedbacks like humidity and ice albedo.   So a modest degree or degree and a half of warming from the greenhouse effect becomes a scary five or eight degrees of warming in the next century once any number of hypothesized positive feedbacks are applied.  Add to this exaggerated, sometimes over-the-top visions of possible negative consequences, and that is how global warming hawks justify massive government action.

OK, that is a very brief description of what I consider a sophisticated reason to be skeptical:  Most catastrophic warming forecasts depend on positive feedback loops, feedbacks for which we have little or no evidence and which don't tend to dominate in other stable systems.  So how many times have you seen this issue discussed?  Zero?  Yeah, its so much easier just to call us deniers.

If you are interested, here is slightly longer version of my skeptic's point of view.  Here is my much longer version.  Here is the specific chapter that discusses feedback loops.  Here is Roy Spencer discussing problems with studies trying to measure these feedbacks.

Postscript:  By the way, it is in this context that the discussions about restating temperatures and problems with historical surface temperature measurements are important.  Exaggerated historical warming numbers leave more room to posit positive feedback loops.  Lower historical numbers, or evidence past warming is driven by non-man-made sources (e.g. solar activity), leave less room to justify positive feedback loops.

Update:  RealClimate has posted their six steps to explain catastrophic warming from CO2.  Seems have buried the feedback issue.  Note that forcings mentioned here include feedbacks, they are not from CO2 alone but from CO2 + positive feedback.  Strange they didn't mention this.

I won't go back into all the details, but I have posted before about just how large the manual adjustments to temperature numbers are (the "noise") as compared to the magnitude of measured warming (the "signal").  This issue of manual temperature corrections is the real reason the NASA temperature restatements are important (not the absolute value of the restatement).

Here is a quick visual example.  Both charts below are from James Hansen and the GISS and are for the US only.  Both use basically the same temperature measurement network (the USHCN).  The one on the left was Hansen's version of US temperatures in 1999.  The one on the right he published in 2001.

The picture at the right is substantially different  than the one on the left.  Just look at 1932 and 1998.  Between the first and second chart, none of the underlying temperature measurements changed.  What changed  were the adjustments to the underlying measurements applied by the NOAA and by the GISS.  For some reason, temperatures after 1980 have been raised and temperatures in the middle of the century were lowered.

For scientists to apply a negative temperature adjustment to measurements, as they did for the early 1930's, it means they think there was some warming bias in 1932 that does not exist today.  When scientists raise current temperatures, they are saying there is some kind of cooling bias that exists today that did not exist in the 1930's.  Both of these adjustments are basically implying the same thing:  That temperature measurement was more biased upwards, say by asphalt and urbanization and poor sitings, in 1932 than they are today.  Does this make any freaking sense at all?

Of course, there may be some other bias at work here that I don't know about.  But I and everyone else in the world are forced to guess because the NOAA and the GISS insist on keeping their adjustment software and details a secret, and continue to resist outside review.

Read much more about this from Steve McIntyre.

I got a lot of traffic this weekend from folks interested in the US historical temperature restatement at NASA-GISS.  I wanted to share to final thoughts and also respond to a post at RealClimate.org (the #1 web cheerleader for catastrophic man-made global warming theory).

1. This restatement does not mean that the folks at GISS are necessarily wrong when they say the world has been warming over the last 20 years.  We know from the independent source of satellite measurements that the Northern Hemisphere has been warming (though not so much in the Southern Hemisphere).  However, surface temperature measurements, particularly as "corrected" and aggregated at the GISS, have always been much higher than the satellite readings.  (GISS vs Satellite)  This incident may start to give us an insight into how to bring those two sources into agreement. 
2. For years, Hansen's group at GISS, as well as other leading climate scientists such as Mann and Briffa (creators of historical temperature reconstructions) have flaunted the rules of science by holding the details of their methodologies and algorithm's secret, making full scrutiny impossible.  The best possible outcome of this incident will be if new pressure is brought to bear on these scientists to stop saying "trust me" and open their work to their peers for review.  This is particularly important for activities such as Hansen's temperature data base at GISS.  While measurement of temperature would seem straight forward, in actual fact the signal to noise ration is really low.  Upward "adjustments" and fudge factors added by Hansen to the actual readings dwarf measured temperature increases, such that, for example, most reported warming in the US is actually from these adjustments, not measured increases.
3. In a week when Newsweek chose to argue that climate skeptics need to shut up, this incident actually proves why two sides are needed for a quality scientific debate.  Hansen and his folks missed this Y2K bug because, as a man-made global warming cheerleader, he expected to see temperatures going up rapidly so he did not think to question the data.  Mr. Hansen is world-famous, is a friend of luminaries like Al Gore, gets grants in quarter million dollar chunks from various global warming believers.  All his outlook and his incentives made him want the higher temperatures to be true.  It took other people with different hypotheses about climate to see the recent temperature jump for what it was: An error.

The general response at RealClimate.org has been:  Nothing to see here, move along.

Among other incorrect stories going around are that the mistake was due
to a Y2K bug or that this had something to do with photographing
weather stations. Again, simply false.

I really, really don't think it matters exactly how the bug was found, except to the extent that RealClimate.org would like to rewrite history and convince everyone this was just a normal adjustment made by the GISS themselves rather than a mistake found by an outsider.  However, just for the record, the GISS, at least for now until they clean up history a bit, admits the bug was spotted by Steven McIntyre.  Whatever the bug turned out to be, McIntyre initially spotted it as a discontinuity that seemed to exist in GISS data around the year 2000.  He therefore hypothesized it was a Y2K bug, but he didn't know for sure because Hansen and the GISS keep all their code as a state secret.  And McIntyre himself says he became aware of the discontinuity during a series of posts that started from a picture of a weather station at Anthony Watts blog.  I know because I was part of the discussion, talking to these folks online in real time.  Here is McIntyre explaining it himself.

In sum, the post on RealClimate says:

Sum total of this change? A couple of hundredths of degrees in the US
rankings and no change in anything that could be considered
climatically important (specifically long term trends).

A bit of background - surface temperature readings have read higher than satellite readings of the troposphere, when the science of greenhouse gases says the opposite should be true.  Global warming hawks like Hansen and the GISS have pounded on the satellite numbers, investigating them 8 ways to Sunday, and have on a number of occasions trumpeted upward corrections to satellite numbers that are far smaller than these downward corrections to surface numbers. 

But yes, IF this is the the only mistake in the data, then this is a mostly correct statement from RealClimate.org..  However, here is my perspective:

• If a mistake of this magnitude can be found by outsiders without access to Hansen's algorithm's or computer code just by inspection of the resulting data, then what would we find if we could actually inspect the code?  And this Y2K bug is by no means the only problem.  I have pointed out several myself, including adjustments for urbanization and station siting that make no sense, and averaging in rather than dropping bad measurement locations. 
• If we know significant problems exist in the US temperature monitoring network, what would we find looking at China? Or Africa?  Or South America.  In the US and a few parts of Europe, we actually have a few temperature measurement points that were rural in 1900 and rural today.  But not one was measuring rural temps in these other continents 100 years ago.  All we have are temperature measurements in urban locations where we can only guess at how to adjust for the urbanization.  The problem in these locations, and why I say this is a low signal to noise ratio measurement, is that small percentage changes in our guesses for how much the urbanization correction should be make enormous changes (even to changing the sign) of historic temperature change measurements.

Here are my recommendations:

1. NOAA and GISS both need to release their detailed algorithms and computer software code for adjusting and aggregating USHCN and global temperature data.  Period.  There can be no argument.  Folks at RealClimate.org who believe that all is well should be begging for this to happen to shut up the skeptics.  The only possible reason for not releasing this scientific information that was created by government employees with taxpayer money is if there is something to hide.
2. The NOAA and GISS need to acknowledge that their assumptions of station quality in the USHCN network are too high, and that they need to incorporate actual documented station condition (as done at SurfaceStations.org) in their temperature aggregations and corrections.  In some cases, stations like Tucson need to just be thrown out of the USHCN.  Once the US is done, a similar effort needs to be undertaken on a global scale, and the effort needs to include people whose incentives and outlook are not driven by making temperatures read as high as possible.
3. This is the easiest of all.  Someone needs to do empirical work (not simulated, not on the computer, but with real instruments) understanding how various temperature station placements affect measurements.  For example, how do the readings of an instrument in an open rural field compare to an identical instrument surrounded by asphalt a few miles away?  These results can be used for step #2 above.  This is cheap, simple research a couple of graduate students could do, but climatologists all seem focused on building computer models rather than actually doing science.
4. Similar to #3, someone needs to do a definitive urban heat island study, to find out how much temperature readings are affected by urban heat, again to help correct in #2.  Again, I want real research here, with identical instruments placed in various locations and various radii from an urban center  (not goofy proxys like temperature vs. wind speed -- that's some scientist who wants to get a result without ever leaving his computer terminal).  Most studies have shown the number to be large, but a couple of recent studies show smaller effects, though now these studies are under attack not just for sloppiness but outright fabrication.  This can't be that hard to study, if people were willing to actually go into the field and take measurements.  The problem is everyone is trying to do this study with available data rather than by gathering new data.

Postscript:  The RealClimate post says:

However, there is clearly a latent and deeply felt wish in some sectors for the whole problem of global warming to be reduced to a statistical quirk or a mistake.

If catastrophic man-made global warming theory is correct, then man faces a tremendous lose-lose.  Either shut down growth, send us back to the 19th century, making us all substantially poorer and locking a billion people in Asia into poverty they are on the verge of escaping, or face catastrophic and devastating changes in the planet's weather.

Now take two people.  One in his heart really wants this theory not to be true, and hopes we don't have to face this horrible lose-lose tradeoff.  The other has a deeply felt wish that this theory is true, and hopes man does face this horrible future.  Which person do you like better?  And recognize, RealClimate is holding up the latter as the only moral man. 

Update:  Don't miss Steven McIntyre's take from the whole thing.  And McIntyre responds to Hansen here.

Editors-

Oh, the delicious irony.

As a skeptic of catastrophic man-made global warming, I was disturbed to see that Newsweek in its August 13, 2007 issue (The Truth About Denial)
had equated me with a Holocaust denier.  There are so many interesting
scientific issues involved in climate change that it was flabbergasting
to me that Newsweek would waste time on an extended ad hominem
attack against one side in a scientific debate.  I was particularly
amazed that Newsweek would accuse the side of the debate that is
outspent 1000:1 with being tainted by money.  This is roughly
equivalent to arguing that Mike Gravel's spending is corrupting the
2008 presidential election.

However, fate does indeed have a sense of humor.  Skeptics' efforts of the sort Newsweek derided just this week
forced NASA-Goddard (GISS) to revise downward recent US temperature
numbers due to a programming mistake that went unidentified for
years, in part because NASA's taxpayer-paid researchers refuse to
release their temperature adjustment and aggregation methodology to the
public for scrutiny.  The problem was found by a chain of events that
began with amateur volunteers and led ultimately to Steven McIntyre (he
of the Michael Mann hockey stick debunking) calling foul.

The particular irony is that the person who is in charge of this
database, and is responsible for the decision not to allow scientific
scrutiny of his methodologies, is none other than James Hansen, who
Newsweek held up as the shining example of scientific objectivity in
its article.  Newsweek should have been demanding that taxpayer-funded
institutions like NASA should be opening their research to full review,
but instead Newsweek chose to argue that Mr. Hansen should be shielded
from scrutiny.

Warren Meyer

This is really big news, and a fabulous example of why two-way scientific discourse is still valuable, in the same week that both Newsweek and Al Gore tried to make the case that climate skeptics were counter-productive and evil. 

Climate scientist Michael Mann (famous for the hockey stick chart) once made the statement that  the 1990's were the
warmest decade in a millennia and that "there is a 95 to 99% certainty
that 1998 was the hottest year in the last one thousand years." (By
the way, Mann now denies he ever made this claim, though you can watch him say
these exact words in the CBC documentary Global
Warming:  Doomsday Called Off).

Well, it turns out, according to the NASA GISS database, that 1998 was not even the hottest year of the last century.  This is because many temperatures from recent decades that appeared to show substantial warming have been revised downwards.  Here is how that happened (if you want to skip the story, make sure to look at the numbers at the bottom).

One of the most cited and used historical surface temperature databases is that of NASA/Goddard's GISS.  This is not some weird skeptics site.  It is considered one of the premier world temperature data bases, and it is maintained by anthropogenic global warming true believers.  It has consistently shown more warming than any other data base, and is thus a favorite source for folks like Al Gore.  These GISS readings in the US rely mainly on the US Historical Climate Network (USHCN) which is a network of about 1000 weather stations taking temperatures, a number of which have been in place for over 100 years.

Frequent readers will know that I have been a participant in an effort led by Anthony Watts at SurfaceStations.org to photo-document these temperature stations as an aid to scientists in evaluating the measurement quality of each station.  The effort has been eye-opening, as it has uncovered many very poor instrument sitings that would bias temperature measurements upwards, as I found in Tucson and Watts has documented numerous times on his blog.

One photo on Watt's blog got people talking - a station in MN with a huge jump in temperature about the same time some air conditioning units were installed nearby.   Others disagreed, and argued that such a jump could not be from the air conditioners, since a lot of the jump happened with winter temperatures when the AC was dormant.  Steve McIntyre, the Canadian statistician who helped to expose massive holes in Michael Mann's hockey stick methodology, looked into it.  After some poking around, he began to suspect that the GISS data base had a year 2000 bug in one of their data adjustments.

One of the interesting aspects of these temperature data bases is that they do not just use the raw temperature measurements from each station.  Both the NOAA (which maintains the USHCN stations) and the GISS apply many layers of adjustments, which I discussed here.  One of the purposes of Watt's project is to help educate climate scientists that many of the adjustments they make to the data back in the office does not necessarily represent the true condition of the temperature stations.  In particular, GISS adjustments imply instrument sitings are in more natural settings than they were in say 1905, an outrageous assumption on its face that is totally in conflict to the condition of the stations in Watt's data base.  Basically, surface temperature measurements have a low signal to noise ratio, and climate scientists have been overly casual about how they try to tease out the signal.

Anyway, McIntyre suspected that one of these adjustments had a bug, and had had this bug for years.  Unfortunately, it was hard to prove.  Why?  Well, that highlights one of the great travesties of climate science.  Government scientists using taxpayer money to develop the GISS temperature data base at taxpayer expense refuse to publicly release their temperature adjustment algorithms or software (In much the same way Michael Mann refused to release the details for scrutiny of his methodology behind the hockey stick).  Using the data, though, McIntyre made a compelling case that the GISS data base had systematic discontinuities that bore all the hallmarks of a software bug.

Today, the GISS admitted that McIntyre was correct, and has started to republish its data with the bug fixed.  And the numbers are changing a lot.  Before today, GISS would have said 1998 was the hottest year on record (Mann, remember, said with up to 99% certainty it was the hottest year in 1000 years) and that 2006 was the second hottest.  Well, no more.  Here are the new rankings for the 10 hottest years in the US, starting with #1:

1934, 1998, 1921, 2006, 1931, 1999, 1953, 1990, 1938, 1939

Three of the top 10 are in the last decade.  Four of the top ten are in the 1930's, before either the IPCC or the GISS really think man had any discernible impact on temperatures.  Here is the chart for all the years in the data base:

There are a number of things we need to remember:

• This is not the end but the beginning of the total reexamination that needs to occur of the USHCN and GISS data bases.  The poor correction for site location and urbanization are still huge issues that bias recent numbers upwards.  The GISS also has issues with how it aggregates multiple stations, apparently averaging known good stations with bad stations a process that by no means eliminates biases.  As a first step, we must demand that NOAA and GISS release their methodology and computer algorithms to the general public for detailed scrutiny by other scientists.
• The GISS today makes it clear that these adjustments only affect US data and do not change any of their conclusions about worldwide data.  But consider this:  For all of its faults, the US has the most robust historical climate network in the world.  If we have these problems, what would we find in the data from, say, China?  And the US and parts of Europe are the only major parts of the world that actually have 100 years of data at rural locations.  No one was measuring temperature reliably in rural China or Paraguay or the Congo in 1900.  That means much of the world is relying on urban temperature measurement points that have substantial biases from urban heat.
• All of these necessary revisions to surface temperatures will likely not make warming trends go away completely.  What it may do is bring the warming down to match the much lower satellite measured warming numbers we have, and will make current warming look more like past natural warming trends (e.g. early in this century) rather than a catastrophe created by man.  In my global warming book, I argue that future man-made warming probably will exist, but will be more like a half to one degree over the coming decades than the media-hyped numbers that are ten times higher.

So how is this possible?  How can the global warming numbers used in critical policy decisions and scientific models be so wrong with so basic of an error?  And how can this error have gone undetected for the better part of a decade?  The answer to the latter question is because the global warming  and climate community resist scrutiny.  This weeks Newsweek article and statements by Al Gore are basically aimed at suppressing any scientific criticism or challenge to global warming research.  That is why NASA can keep its temperature algorithms secret, with no outside complaint, something that would cause howls of protest in any other area of scientific inquiry.

As to the first question, I will leave the explanation to Mr. McIntyre:

While acolytes may call these guys "professionals", the process of
data adjustment is really a matter of statistics and even accounting.
In these fields, Hansen and Mann are not "professionals" - Mann
admitted this to the NAS panel explaining that he was "not a
statistician". As someone who has read their works closely, I do not
regard any of these people as "professional". Much of their reluctance
to provide source code for their methodology arises, in my opinion,
because the methods are essentially trivial and they derive a certain
satisfaction out of making things appear more complicated than they
are, a little like the Wizard of Oz. And like the Wizard of Oz, they
are not necessarily bad men, just not very good wizards.

For more, please see my Guide to Anthropogenic Global Warming or, if you have less time, my 60-second argument for why one should be skeptical of catastrophic man-made global warming theory.

Update: Nothing new, just thinking about this more, I cannot get over the irony that in the same week Newsweek makes the case that climate science is settled and there is no room for skepticism, skeptics discover a gaping hole and error in the global warming numbers.

Update #2:  I know people get upset when we criticize scientists.  I get a lot of "they are not biased, they just made a mistake."  Fine.  But I have zero sympathy for a group of scientists who refuse to let other scientists review their methodology, and then find that they have been making a dumb methodology mistake for years that has corrupted the data of nearly every climate study in the last decade.

Update #3:  I labeled this "breaking news," but don't expect to see it in the NY Times anytime soon.  We all know this is one of those asymmetric story lines, where if the opposite had occurred (ie things found to be even worse/warmer than thought) it would be on the front page immediately, but a lowered threat will never make the news.

Oh, and by he way.  This is GOOD news.  Though many won't treat it that way.  I understand this point fairly well because, in a somewhat parallel situation, I seem to be the last anti-war guy who treats progress in Iraq as good news.

Update #4: I should have mentioned that the hero of the Newsweek story is catastrophic man-made global warming cheerleader James Hansen, who runs the GISS and is most responsible for the database in question as well as the GISS policy not to release its temperature aggregation and adjustment methodologies.  From IBD, via CNN Money:

Newsweek portrays James Hansen, director of NASA's Goddard Institute for Space Studies, as untainted by corporate bribery.

Hansen
was once profiled on CBS' "60 Minutes" as the "world's leading
researcher on global warming." Not mentioned by Newsweek was that
Hansen had acted as a consultant to Al Gore's slide-show presentations
on global warming, that he had endorsed John Kerry for president, and
had received a $250,000 grant from the foundation headed by Teresa
Heinz Kerry.

Update #5: My letter to the editor at Newsweek.  For those worried that this is some weird skeptic's fevered dream, Hansen and company kind of sort of recognize the error in the first paragraph under background here.  Their US temperature chart with what appears is the revised data is here.

Update #6: Several posts are calling this a "scandal."  It is not a scandal.  It is a mistake from which we should draw two lessons:

1. We always need to have people of opposing opinions looking at a problem.  Man-made global warming hawks expected to see a lot of warming after the year 2000, so they never questioned the numbers.  It took folks with different hypotheses about climate to see the jump in the numbers for what it was - a programming error.
2. Climate scientists are going to have to get over their need to hold their adjustments, formulas, algorithms and software secret.  It's just not how science is done.  James Hansen saying "trust me, the numbers are right, I don't need to tell you how I got them" reminds me of the mathematician Fermat saying he had a proof of his last theorem, but it wouldn't fit in the margin.  How many man-hours of genius mathematicians was wasted because Fermat refused to show his proof (which was most likely wrong, given how the theorem was eventually proved).

Final Update:  Some parting thoughts, and recommendations, here.

Update:  My post on breaking news about downward revisions to US temperature numbers is here.

Well, I finally read Newsweek's long ad hominem attack on climate skeptics in the recent issue.  It is basically yet another take on the global-warming-skeptics-are-all-funded-by-Exxon meme.  The authors breathlessly "follow the money to show how certain scientists have taken as much as $10,000 (gasp) from fossil-fuel related companies to publish skeptical work.  Further, despite years of hand-wringing about using emotionally charged words like "terrorist" in their news articles, Newsweek happily latches onto "denier" as a label for skeptics, a word chosen to parallel the term "Holocaust denier" -- nope, no emotional content there.

I'm not even going to get into it again, except to make the same observation I have made in the past:  Arguing that the global warming debate is "tainted" by money from skeptics is like saying the 2008 presidential election is tainted by Mike Gravel's spending.  Money from skeptics is so trivial, by orders of magnitude, compared to spending by catastrophic warming believers that it is absolutely amazing folks like Newsweek could feel so threatened by it.  In my Layman's Guide To Man-Made Global Warming Skepticism, I estimated skeptics were being outspent 1000:1.  I have no way to check his figures, but Senator Inhofe's office estimated skeptics were being outspent $50 billion to 19 million, which is about the same order of magnitude as my estimate.

Given this skew in spending, and the fact that most of the major media accepts catastrophic man-made  global warming as a given, this was incredible:

Look for the next round of debate to center on what Americans are
willing to pay and do to stave off the worst of global warming. So far
the answer seems to be, not much. The NEWSWEEK Poll finds less than half in favor of requiring high-mileage cars or energy-efficient appliances and buildings....

Although the figure is less than in earlier polls, A new NEWSWEEK Poll finds that the influence of the denial machine remains strong.39
percent of those asked say there is "a lot of disagreement among
climate scientists" on the basic question of whether the planet is
warming; 42 percent say there is a lot of disagreement that human
activities are a major cause of global warming. Only 46 percent say the
greenhouse effect is being felt today.

It has to be the "denial machine" at fault, right?  I can't possibly be because Americans think for themselves, or that they tend to reject micro-managing government regulations.  The author sounds so much like an exasperated parent "I kept telling my kids what's good for them and they just don't listen."

Yes, I could easily turn the tables here, and talk about the financial incentives in academia for producing headlines-grabbing results, or discuss the political motivations behind Marxist groups who have latched onto man-made global warming for their own ends.  But this does not really solve the interesting science questions, and ignores the fact that many catastrophic climate change believers are well meaning and thoughtful, just as many skeptics are.  The article did not even take the opportunity to thoughtfully discuss the range of skeptic's positions.  Some reject warming entirely, while others, like myself, recognize the impact man can have on climate, but see man's impact being well below catastrophic levels (explained here in 60 seconds).  Anyway, I don't have the energy to fisk it piece by piece, but Noel Sheppard does.

For those of you who are interested, I have a follow-up post on the science itself, which is so much more interesting that this garbage.  I use as a starting point the Newsweek author's throwaway statement that she felt required no proof, "The frequency of Atlantic hurricanes has already doubled in the last century."  (Hint:  the answer turns out to be closer to +5% than +100%)

On several occasions, I have discussed how much of the reported temperature increases worldwide in the last century are actually the results of adjustments to the actual gauge measurements.  These upward adjustments in the numbers by climate scientists actually dwarf measured increases.

Thanks to reader Scott Brooks, here is another such example except this time with measurement of sea level increases.  Dr. Nils-Axel Morner is the head of the Paleogeophysics and Geodynamics department at Stockholm University in Sweden.  He has studied sea-level changes for 35 years (emphasis added).

Another
way of looking at what is going on is the tide gauge. Tide gauging is
very complicated, because it gives different answers for wherever you
are in the world. But we have to rely on geology when we interpret it.
So, for example, those people in the IPCC [Intergovernmental Panel on
Climate Change], choose Hong Kong, which has six tide gauges, and they
choose the record of one, which gives 2.3 mm per year rise of sea
level. Every geologist knows that that is a subsiding area. It's the
compaction of sediment; it is the only record which you shouldn't use.
And if that figure [for sea level rise] is correct, then Holland would not be subsiding, it
would be uplifting.

And
that is just ridiculous. Not even ignorance could be responsible for a
thing like that. So tide gauges, you have to treat very, very
carefully. Now, back to satellite altimetry, which shows the water, not
just the coasts, but in the whole of the ocean. And you measure it by
satellite. From 1992 to 2002, [the graph of the sea level] was a
straight line, variability along a straight line, but absolutely no
trend whatsoever. We could see those spikes: a very rapid rise, but
then in half a year, they fall back again. But absolutely no trend, and
to have a sea-level rise, you need a trend.

Then,
in 2003, the same data set, which in their [IPCC's] publications, in
their website, was a straight line suddenly it changed, and showed a
very strong line of uplift, 2.3 mm per year, the same as from the tide
gauge. And that didn't look so nice. It looked as though they had
recorded something; but they hadn't recorded anything. It was the
original one which they had suddenly twisted up, because they entered a correction factor, which they took from the tide gauge. So it was not
a measured thing, but a figure introduced from outside. I accused them
of this at the Academy of Sciences in Moscow I said you have
introduced factors from outside; it's not a measurement. It looks like
it is measured from the satellite, but you don't say what really
happened. And they ans-wered, that we had to do it, because otherwise
we would not have gotten any trend!

That
is terrible! As a matter of fact, it is a falsification of the data
set. Why? Because they know the answer. And there you come to the
point: They know the answer; the rest of us, we are searching for the
answer. Because we are field geologists; they are computer scientists.
So all this talk that sea level is rising, this stems from the computer
modeling, not from observations. The observations don't find it!

I have
been the expert reviewer for the IPCC, both in 2000 and last year. The
first time I read it, I was exceptionally surprised. First of all, it
had 22 authors, but none of them  none were sea-level specialists. They
were given this mission, because they promised to answer the right
thing. Again, it was a computer issue. This is the typical thing: The meteorological community works with computers, simple computers.

Geologists
don't do that! We go out in the field and observe, and then we can try
to make a model with computerization; but it's not the first thing.

I am working on my next version of a layman's guide to skeptics arguments against catastrophic man-made global warming, which you can find here.

On several occasions, I have discussed how much of the reported temperature increases worldwide in the last century are actually the results of adjustments to the actual gauge measurements.  These upward adjustments in the numbers by climate scientists actually dwarf measured increases.

Thanks to reader Scott Brooks, here is another such example except this time with measurement of sea level increases.  Dr. Nils-Axel Morner is the head of the Paleogeophysics and Geodynamics department at Stockholm University in Sweden.  He has studied sea-level changes for 35 years (emphasis added).

Another
way of looking at what is going on is the tide gauge. Tide gauging is
very complicated, because it gives different answers for wherever you
are in the world. But we have to rely on geology when we interpret it.
So, for example, those people in the IPCC [Intergovernmental Panel on
Climate Change], choose Hong Kong, which has six tide gauges, and they
choose the record of one, which gives 2.3 mm per year rise of sea
level. Every geologist knows that that is a subsiding area. It's the
compaction of sediment; it is the only record which you shouldn't use.
And if that figure [for sea level rise] is correct, then Holland would not be subsiding, it
would be uplifting.

And
that is just ridiculous. Not even ignorance could be responsible for a
thing like that. So tide gauges, you have to treat very, very
carefully. Now, back to satellite altimetry, which shows the water, not
just the coasts, but in the whole of the ocean. And you measure it by
satellite. From 1992 to 2002, [the graph of the sea level] was a
straight line, variability along a straight line, but absolutely no
trend whatsoever. We could see those spikes: a very rapid rise, but
then in half a year, they fall back again. But absolutely no trend, and
to have a sea-level rise, you need a trend.

Then,
in 2003, the same data set, which in their [IPCC's] publications, in
their website, was a straight line suddenly it changed, and showed a
very strong line of uplift, 2.3 mm per year, the same as from the tide
gauge. And that didn't look so nice. It looked as though they had
recorded something; but they hadn't recorded anything. It was the
original one which they had suddenly twisted up, because they entered a correction factor, which they took from the tide gauge. So it was not
a measured thing, but a figure introduced from outside. I accused them
of this at the Academy of Sciences in Moscow I said you have
introduced factors from outside; it's not a measurement. It looks like
it is measured from the satellite, but you don't say what really
happened. And they ans-wered, that we had to do it, because otherwise
we would not have gotten any trend!

That
is terrible! As a matter of fact, it is a falsification of the data
set. Why? Because they know the answer. And there you come to the
point: They know the answer; the rest of us, we are searching for the
answer. Because we are field geologists; they are computer scientists.
So all this talk that sea level is rising, this stems from the computer
modeling, not from observations. The observations don't find it!

I have
been the expert reviewer for the IPCC, both in 2000 and last year. The
first time I read it, I was exceptionally surprised. First of all, it
had 22 authors, but none of them  none were sea-level specialists. They
were given this mission, because they promised to answer the right
thing. Again, it was a computer issue. This is the typical thing: The meteorological community works with computers, simple computers.

Geologists
don't do that! We go out in the field and observe, and then we can try
to make a model with computerization; but it's not the first thing.

I am working on my next version of a layman's guide to skeptics arguments against catastrophic man-made global warming, which you can find here.

New study results, via Tyler Cowen:

We estimate the effect of extreme weather on life expectancy in the US. ... However, the
increase in mortality following extreme heat appears entirely driven by
temporal displacement, while the increase in mortality following
extreme cold is long lasting. The aggregate effect of cold on mortality
is quantitatively large. We estimate that the number of annual deaths
attributable to cold temperature is 27,940 or 1.3% of total deaths in
the US. This effect is even larger in low income areas. Because the
U.S. population has been moving from cold Northeastern states to the
warmer Southwestern states, our findings have implications for
understanding the causes of long-term increases in life expectancy. We
calculate that every year, 5,400 deaths are delayed by changes in
exposure to cold temperature induced by mobility. These longevity gains
associated with long term trends in geographical mobility account for
8%-15% of the total gains in life expectancy experienced by the US
population over the past 30 years. Thus mobility is an important but
previously overlooked determinant of increased longevity in the United
States. We also find that the probability of moving to a state that has
fewer days of extreme cold is higher for the age groups that are
predicted to benefit more in terms of lower mortality compared to the
age groups that are predicted to benefit less.

Your welcome, America. 

Steve McIntyre, the statistician than called into question much of the methodology behind the Mann Hockey Stick chart, has some observations on adjustments to US temperature records I discussed here and here.

Eli Rabett and Tamino have both advocated faith-based climate
science in respect to USHCN and GISS adjustments. They say that the
climate "professionals" know what they're doing; yes, there are
problems with siting and many sites do not meet even minimal compliance
standards, but, just as Mann's "professional" software was able to
extract a climate signal from the North American tree ring data, so
Hansen's software is able to "fix" the defects in the surface sites.
"Faith-based" because they do not believe that Hansen has any
obligation to provide anything other than a cursory description of his
software or, for that matter, the software itself. But if they are
working with data that includes known bad data, then critical
examination of the adjustment software becomes integral to the
integrity of the record - as there is obviously little integrity in
much of the raw data.

While acolytes may call these guys "professionals", the process of
data adjustment is really a matter of statistics and even accounting.
In these fields, Hansen and Mann are not "professionals" - Mann
admitted this to the NAS panel explaining that he was "not a
statistician". As someone who has read their works closely, I do not
regard any of these people as "professional". Much of their reluctance
to provide source code for their methodology arises, in my opinion,
because the methods are essentially trivial and they derive a certain
satisfaction out of making things appear more complicated than they
are, a little like the Wizard of Oz. And like the Wizard of Oz, they
are not necessarily bad men, just not very good wizards.

He goes on to investigate a specific example the "professionals" use
as a positive example, demonstrating they appear to have a Y2K error in
their algorithm.   This is difficult to do, because like Mann, government scientists maintaining a government temperature data base taken from government sites paid for with taxpayer funds refuse to release their methodology or algorithms for inspection.

In the case cited, the "professionals" also make adjustments that imply the site has
decreasing urbanization over the last 100 years, something I am not
sure one can say about any site in the US except perhaps for a few
Colorado ghost towns.  The "experts" also fail to take the basic step of actually analyzing the site itself which, if visited, would reveal recently installed air conditioning unites venting hot air on the temperature instrument.   

A rebuttal, arguing that poor siting of temperature instruments is OK and does not affect the results is here.  I find rebuttals of this sort really distressing.  I studied physics for a while, before switching to engineering, and really small procedural mistakes in measurement could easily invalidate one's results.  I find it amazing that climate scientists seek to excuse massive mistakes in measurement.  I'm sorry, but in no other branch of science are results considered "settled" when the experimental noise is greater than the signal.  I would really, really, just for once, love to see a anthropogenic global warming promoter say "well, I don't think the siting will change the results, but you are right, we really need to go back and take another pass at correcting historical temperatures based on more detailed analysis of the individual sites."

A few posts back, I showed how nearly 85% of the reported warming in the US over the last century is actually due to adjustments and added fudge-factors by scientists rather than actual measured higher temperatures.  I want to discuss some further analysis Steve McIntyre has done on these adjustments, but first I want to offer a brief analogy.

Let's say you had two compasses to help you find north, but the compasses are reading incorrectly.  After some investigation, you find that one of the compasses is located next to a strong magnet, which you have good reason to believe is strongly biasing that compass's readings.  In response, would you

1. Average the results of the two compasses and use this mean to guide you, or
2. Ignore the output of the poorly sited compass and rely solely on the other unbiased compass?

Most of us would quite rationally choose #2.  However, Steve McIntyre shows us a situation involving two temperature stations in the USHCN network in which government researchers apparently have gone with solution #1.  Here is the situation:

He compares the USHCN station at the Grand Canyon (which appears to be a good rural setting) with the Tucson USHCN station I documented here, located in a parking lot in the center of a rapidly growing million person city.   Unsurprisingly, the Tucson data shows lots of warming and the Grand Canyon data shows none.  So how might you correct Tucson and the Grand Canyon data, assuming they should be seeing about the same amount of warming?  Would you
average them, effectively adjusting the two temperature readings
towards each other, or would you assume the Grand Canyon data is cleaner
with fewer biases and adjust Tucson only?   Is there anyone who would not choose the second option, as with the compasses?

The GISS data set, created by the Goddard Center of NASA, takes the USHCN data set and somehow uses nearby stations to correct for anomalous stations.  I say somehow, because, incredibly, these government scientists, whose research is funded by taxpayers and is being used to make major policy decisions, refuse to release their algorithms or methodology details publicly.  They keep it all secret!  Their adjustments are a big black box that none of us are allowed to look into  (and remember, these adjustments account for the vast majority of reported warming in the last century).

We can, however, reverse engineer some of these adjustments, and McIntyre does.  What he finds is that the GISS appears to be averaging the good and bad compass, rather than throwing out or adjusting only the biased reading.  You can see this below.  First, here are the USHCN data for these two stations with only the Time of Observation adjustment made (more on what these adjustments are in this article).

As I said above, no real surprise - little warming out in undeveloped nature, lots of warming in a large and rapidly growing modern city.  Now, here is the same data after the GISS has adjusted it:

You can see that Tucson has been adjusted down a degree or two, but Grand Canyon has been adjusted up a degree or two (with the earlier mid-century spike adjusted down).  OK, so it makes sense that Tucson has been adjusted down, though there is a very good argument to be made that it should be been adjusted down more, say by at least 3 degrees**.  But why does the Grand Canyon need to be adjusted up by about a degree and a half?  What is biasing it colder by 1.5 degrees, which is a lot?  The answer:  Nothing.  The explanation:  Obviously, the GISS is doing some sort of averaging, which is bringing the Grand Canyon and Tucson from each end closer to a mean. 

This is clearly wrong, like averaging the two compasses.  You don't average a measurement known to be of good quality with one known to be biased.  The Grand Canyon should be held about the same, and Tucson adjusted down even more toward it, or else thrown out.  Lets look at two cases.  In one, we will use the GISS approach to combine these two stations-- this adds 1.5 degrees to GC and subtracts 1.5 degrees from Tucson.  In the second, we will take an approach that applies all the adjustment to just the biases (Tucson station) -- this would add 0 degrees to GC and subtract 3 degrees from Tucson.  The first approach, used by the GISS, results in a mean warming in these two stations that is 1.5 degrees higher than the more logical second approach.  No wonder the GISS produces the highest historical global warming estimates of any source!  Steve McIntyre has much more.

** I got to three degrees by applying all of the adjustments for GC and Tucson to Tucson.  Here is another way to get to about this amount.   We know from studies that urban heat islands can add 8-10 degrees to nighttime urban temperatures over surrounding undeveloped land.  Assuming no daytime effect, which is conservative, we might conclude that 8-10 degrees at night adds about 3 degrees to the entire 24-hour average.

Postscript: Steve McIntyre comments (bold added):

These adjustments are supposed to adjust for station moves - the
procedure is described in Karl and Williams 1988 [check], but, like so
many climate recipes, is a complicated statistical procedure that is
not based on statistical procedures known off the island. (That's not
to say that the procedures are necessarily wrong, just that the
properties of the procedure are not known to statistical civilization.)
When I see this particular outcome of the Karl methodology, my
impression is that, net of the pea moving under the thimble, the Grand
Canyon values are being blended up and the Tucson values are being
blended down. So that while the methodology purports to adjust for
station moves, I'm not convinced that the methodology can successfully
estimate ex post the impact of numerous station moves and my guess is
that it ends up constructing a kind of blended average.

LOL.  McIntyre, by the way, is the same gentleman who helped call foul on the Mann hockey stick for bad statistical procedure.

The US Historical Climate Network (USHCN) reports about a 0.6C temperature increase in the lower 48 states since about 1940.  There are two steps to reporting these historic temperature numbers.  First, actual measurements are taken.  Second, adjustments are made after the fact by scientists to the data.  Would you like to guess how much of the 0.6C temperature rise is from actual measured temperature increases and how much is due to adjustments of various levels of arbitrariness?  Here it is, for the period from 1940 to present in the US:

Yes, that is correct.  Nearly all the reported warming in the USHCN data base, which is used for nearly all global warming studies and models, is from human-added fudge factors, guesstimates, and corrections.

I know what you are thinking - this is some weird skeptic's urban legend.  Well, actually it comes right from the NOAA web page which describes how they maintain the USHCN data set.  Below is the key chart from that site showing the sum of all the plug factors and corrections they add to the raw USHCN measurements:

I hope you can see this significance.  Before we get into whether these measurements are right or wrong or accurate or guesses, it is very useful to understand that almost all the reported warming in the US over the last 70 years is attributable to the plug figures and corrections a few government scientists add to the data in the back room.  It kind of reduces one's confidence, does it not, in the basic conclusion about catastrophic warming? 

Anyway, lets look at the specific adjustments.  The lines in the chart below should add to the overall adjustment line in the chart above.

• Black line is a time of observation adjustment, adding about 0.3C since 1940
• Light Blue line is a missing data adjustment that does not affect the data much since 1940
• Red line is an adjustment for measurement technologies, adding about 0.05C since 1940
• Yellow line is station location quality adjustment, adding about 0.2C since 1940
• Purple line is an urban heat island adjustment, subtracting about 0.05C since 1950.

Let's take each of these in turn.  The time of observation adjustment is defined as follows:

The Time of Observation Bias (TOB) arises when the 24-hour daily
summary period at a station begins and ends at an hour other than local
midnight. When the summary period ends at an hour other than midnight,
monthly mean temperatures exhibit a systematic bias relative to the
local midnight standard

0.3C seems absurdly high for this adjustment, but I can't prove it.  However, if I understand the problem, a month might be picking up a few extra hours from the next month and losing a few hours to the previous month.  How is a few hour time shift really biasing a 720+ hour month by so large a number? I will look to see if I can find a study digging into this. 

I will skip over the missing data and measurement technology adjustments, since they are small.

The other two adjustments are fascinating.  The yellow line says that siting has improved on USHCN sites such that, since 1900, their locations average 0.2C cooler due to being near more grass and less asphalt today than in 1900. 

During this time, many sites were relocated from city locations to
airports and from roof tops to grassy areas. This often resulted in
cooler readings than were observed at the previous sites.

OK, without a bit of data, does that make a lick of sense?  Siting today in our modern world has GOT to be worse than it was in 1900 or even 1940.  In particular, the very short cable length of the newer MMTS sensors that are standard for USHCN temperature measurement guarantee that readings today are going to be close to buildings and paving.  Now, go to SurfaceStations.org and look at pictures of actual installations, or look at the couple of installations in the Phoenix area I have taken pictures of here.  Do these look more grassy and natural than measurement sites were likely to be in 1900?  Or go to Anthony Watts blog and scroll down his posts on horrible USHCN sites.

The fact is that not only is NOAA getting this correction wrong, but it probably has the SIGN wrong.  The NOAA has never conducted the site by site survey that we discussed above.  Their statement that locations are improving is basically a leap of faith, rather than a fact-based conclusion.  In fact, NOAA scientists who believe that global warming is a problem tend to overlay this bias on the correction process.  Note the quote above -- temperatures that don't increase as they expect are treated as an error to be corrected, rather than a measurement that disputes their hypothesis.

Finally, lets look the urban heat island adjustment.  The NOAA is claiming that the sum total of urban heat island effects on its network since 1900 is just 0.1C, and less than 0.05C since 1940.  We're are talking about the difference between a rural America with horses and dirt roads and a modern urban society with asphalt and air conditioning and cars.  This rediculously small adjustment reflects two biases among anthropogenic global warming advocates:  1)  That urban heat island effects are negligible and 2) That the USHCN network is all rural.  Both are absurd.  Study after study has show urban heat island effects as high as 6-10 degrees.  Just watch you local news if you live in a city --  you will see actual temperatures and forecasts lower by several degrees in the outlying areas than in the center of town.  As to the locations all being rural, you just have to go to surfacestations.org and see where these stations are.  Many of these sites might have been rural in 1940, but they have been engulfed by cities and towns since.

To illustrate both these points, lets take the case of the Tucson site I visited.  In 1900, Tucson was a dusty one-horse town (Arizona was not even a state yet).  In 1940, it was still pretty small.  Today, it is a city of over one million people and the USHCN station is dead in the center of town, located right on an asphalt parking lot.  The adjustment NOAA makes for all these changes?  Less than one degree.  I don't think this is fraud, but it is willful blindness.

So, let's play around with numbers.  Let's say that instead of a 0.2C site quality adjustment we instead used a -0.1C adjustment, which is still probably generous.  Let's assume that instead of a -0.05C urban adjustment we instead used -0.2C.  The resulting total adjustment from 1940 to date would be +0.05 and the total measurement temperature increase in the US would fall from 0.6C to 0.15C.  And this is without even changing the very large time of observation adjustment, and is using some pretty conservative assumptions on my part.  Wow!  This would put US warming more in the range of what satellite data would imply, and would make it virtually negligible. It means that the full amount of reported US warming may well be within the error bars for the measurement network and the correction factors.

While anthropogenic global warming enthusiasts are quick to analyze the reliability of any temperature measurement that shows lower global warming numbers (e.g. satellite), they have historically resisted calls to face up to the poor quality of surface temperature measurement and the arbitrariness of current surface temperature correction factors.  As the NOAA tellingly states:

The U.S. Historical Climatology Network (USHCN, Karl et al. 1990)
is a high-quality moderate sized data set of monthly averaged maximum,
minimum, and mean temperature and total monthly precipitation developed
to assist in the detection of regional climate change. The USHCN is
comprised of 1221 high-quality stations from the U.S. Cooperative
Observing Network within the 48 contiguous United States.

Does it sound defensive to anyone else when they use "high-quality" in both of the first two sentences?  Does anyone think this is high quality?  Or this?  Or this?  Its time to better understand what this network as well as its limitations.

My 60-second climate skepticism argument is here.  The much longer paper explaining the breath of skeptic's issues with catastrophic man-made global warming is available for free here.

PS- This analysis focuses only on the US.  However, is there anyone out there who thinks that measurement in China and India and Russia and Africa is less bad?

Update-  This pdf has an overview of urban heat islands, including this analysis showing the magnitude of the Phoenix nighttime UHI as well as the fact that this UHI has grown substantially over the last 30 years.

Update2: Steve McIntyre looks at temperature adjustments for a couple of California Stations.  In one case he finds a station that has not moves for over one hundred years getting an adjustment that implies a urban heat island reduction over the past 100 years.

Yep, I admit it, air conditioning may indeed be causing us to measure higher temperatures.  Here is the historic temperature plot of Detroit Lake, MN, one of the thousand or so measurement points in the data base that is used to compute historical warming in the US.

Look at that jump in the last 10 years.  It must be global warming!  Can't possibly be due to these air conditioning units installed around 2000 and venting hot gas on the temperature instrument (in that round louvered thing on the post).

More from Anthony Watts, who is leading the effort to document all these stations. You too can help.  The odds are you live less than an hour from one of these stations -- take your camera and add it to the data base.  Its fun!

Incredibly, the global warming community still argues that documenting the quality of the installations used in the official global warming numbers is unnecessary.  More air conditioners blowing on official temperature measurements here.  Worst temperature installation found to date here, "coincidently" at the site with the highest measured 20th century warming.

I got to make a real contribution to science this weekend, and I will explain below how you can too.  First, some background.

A while back, Steve McIntyre was playing around with graphing temperature data form the US Historical Climate Network (USHCN).  This is the data that is used in most global warming studies and initializes most climate models.  Every climate station is not in this data base - in fact, only about 20 per state are in the data base, with locations supposedly selected in rural areas less subject to biases over time from urban development (urban areas are hotter, due to pavement and energy use, for reasons unrelated to the greenhouse effect).  The crosses below on the map show each station.

He showed this graph, of the USHCN data for temperature change since 1900 (data corrected for time of day of measurement).  Redder shows measured temperatures have increased since 1900, bluer means they have decreased.

He mentioned that Tucson was the number one warming site -- you can see it in the deepest red.  My first thought was, "wow, that is right next door to me."   My second thought was "how can Tucson, with a million people, count as rural?"   Scientists who study global warming apply all kinds of computer and statistical tricks to this data, supposedly to weed out measurement biases and problems.  However, a number of folks have been arguing that scientists really need to evaluate biases site by site.  Anthony Watts has taken this idea and created SurfaceStations.org, a site dedicated to surveying and photographing these official USHCN stations.

So, with his guidance, I went down to Tucson to see for myself.  My full report is here, but this is what I found:

The measurement station is in the middle of an asphalt parking lot!  This is against all best practices, and even a layman can see how that would bias measurements high.  Watts finds other problems with the installation from my pictures that I missed, and comments here that it is the worst station he has seen yet.  That, by the way, is the great part about this exercise.  Amateurs like me don't need to be able to judge the installation, they just need to take good pictures that the experts can use to analyze problems.

As a final note on Tucson, during the time period between 1950 and today, when Tucson saw most of this measured temperature increase, the population of Tucson increased from under 200,000 to over 1,000,000.  That's a lot of extra urban heat, in addition to the local effects of this parking lot.

The way that scientists test for anomalies without actually visiting or looking at the sites is to do some statistical checks against other nearby sites.  Two such sites are Mesa and Wickenburg.  Mesa immediately set off alarm bells for me.  Mesa is a suburb of Phoenix, and is often listed among the fastest growing cities in the country.  Sure enough, the Mesa temperature measurements were discontinued in the late 1980's, but surely were biased upwards by urban growth up to that time.

So, I then went to visit Wickenburg.  Though is has been growing of late, Wickenburg would still be considered by most to be a small town.  So perhaps the Wickenburg measurement is without bias?  Well, here is the site:

That white coffee can looking thing on a pole in the center is the temperature instrument.  Again, we have it surrounded by a sea of black asphalt, but we also have two building walls that reflect heat onto the instrument.  Specs for the USHCN say that instruments should be installed in an open area away from buildings and on natural ground.  Oops.  Oh, and by the way, lets look the other direction...

What are those silver things just behind the unit?  They are the cooling fans for the building's AC.  Basically, all the heat from the building removed by the AC gets dumped out about 25 feet from this temperature measurement.

Remember, these are the few select stations being used to determine how much global warming the US is experiencing.  Pretty scary.  Another example is here.

Believe it or not, for all the work and money spent on global warming, this is something that no one had done -- actually go document these sites to check their quality and potential biases.  And you too can have the satisfaction of contributing to science.  All you need is a camera (a GPS of some sort is also helpful).  I wrote a post with instructions on how to find temperature stations near you and how to document them for science here.

For those interested, my paper on the skeptics' arguments against catastrophic man-made global warming is here.  If that is too long, the 60-second climate skeptic pitch is here.

I was trying to think about what I wanted to do for my last post in my recent orgy of global warming writing.  My original attempt to outline the state of the climate skeptic's case ballooned into 80+ pages, so there may be many people who rationally just have no desire to tackle that much material.  So I decided for this last post to try to select the one argument I would use if I had only 60 seconds to make the climate skeptic's case. But how do you boil down 80 pages to a few simple statements?

I'm not that interested in the Sun or cosmic rays -- they are interesting topics, but its dumb to try to argue we overestimate our understanding of man's impact on climate only to counter with topics we understand even less.  One of the reasons I wrote the paper in the first place was because I thought recent skeptical documentaries spent too much time on this subject.  And I would not get into tree rings or ice cores or other historic proxy data, though there is a lot happening in these areas.  I wouldn't even delve into the hysterical treatment of skeptics by man-made climate advocates  -- these are ad hominem issues that are useful to understand in a more comprehensive view but don't make for strong stand-alone arguments.

Anyway, here goes, in a logic chain of 8 steps.

1. CO2 does indeed absorb reflected sunlight returning to space from earth, having a warming effect.  However, this effect is a diminishing return -- each successive increment of CO2 concentrations will have a much smaller effect on temperatures than the previous increment.  Eventually, CO2 becomes nearly saturated in its ability to absorb radiation.  The effect is much like painting a red room with white paint.  The first coat covers a lot of red but some still shows through.  Each additional coat will make the room progressively whiter, but each successive coat will have a less noticeable effects than the previous coat, until the room is just white and can't get any whiter.
2. In the 20th century, the UN IPCC claims Earth's surface temperatures have increased by about a 0.6 degree Celsius (though there are some good reasons to think that biases in the installation of temperature instruments have exaggerated this apparent increase).  To be simple (and generous), let's assume all this 0.6C increase is due to man-made greenhouse gasses.  Some may in fact have been due to natural effects, but some may also have been masked by man-made sulfate aerosols, so lets just call man-made warming to be 0.6C. 
3. Since the beginning of the industrial revolution, it is thought that man has increased atmospheric CO2 concentrations from 0.028% of the atmosphere to 0.038% of the atmosphere.  Since scientists often talk about the effect of a doubling of CO2, this historic rise in CO2 is 36% of a doubling.
4. Using simple math, we see that if temperatures have risen 0.6C due to 36% of a doubling, we might expect them to rise by 1.67C for a full doubling to 0.056% of the atmosphere.  But this assumes that the rise is linear -- and we already said (and no one denies) that it is in fact a diminishing return relationship.  Using a truer form of the curve, a 0.6C historic rise for 36% of a doubling implies a full doubling would raise temperatures by about 1.2C, or about 0.6C more than we have seen to date (see chart below).   This means that the magnitude of global warming in the next century might be about what we have seen (and apparently survived) since 1900.



5. Obviously, there is some kind of disconnect here.  The IPCC predicts temperature increases in the next century of 4-8 degrees C.  Big difference.  In fact, the IPCC predicts we will get a 0.5C rise in just 20 years, not 70-100.  Whereas we derived a climate sensitivity of 1.2 from empirical data, they arrive at numbers between 3 and 4 or even higher for sensitivity.  The chart below shows that to believe sensitivity is 3, we would have to have seen temperature rises due to man historically of 1.5C, which nobody believes. 

   

   So how do they get accelerating temperatures from what they admit to be a diminishing return relation between CO2 concentration and temperature? And for which there is no empirical evidence?  Answer:  Positive feedback.

6. Almost every process you can think of in nature operates by negative
   feedback.  Roll a ball, and eventually friction and wind resistance bring
   it to a stop.  Negative feedback is a ball in the bottom of a bowl; positive feedback is a ball perched precariously at the time of a mountain. Positive feedback
   breeds instability, and processes that operate by positive feedback are
   dangerous, and usually end up in extreme states -- these processes tend to
   "run away" like the ball rolling down the hill.  Nuclear fission, for example, is a positive feedback process.  We should be happy there are not more positive feedback
   processes on our planet.  Current man-made global warming theory, however, asserts that our climate is dominated by positive feedback.  The IPCC posits that a small increase in temperature from CO2 is multiplied 2,3,4 times or more by positive feedbacks like humidity and ice albedo.
7. There are three problems with these assumptions about positive feedback.  One, there is no empirical evidence at all that positive feedbacks in climate dominate negative feedbacks.   The 20th century temperature numbers we discussed above show no evidence of these feedbacks.  Two, the long-term temperature record demonstrates that positive feedbacks can't dominate, because past increases in temperature and CO2 have not run away.  And three, characterizations of stable natural processes as being dominated by positive feedback should offend the intuition and common sense of any scientist.
8. An expected 21st century increase of 0.5 or even 1 degree C does not justify the massive imposed government interventions that will be costly both in dollars and lost freedoms.  In particular, the developing world will be far better off hotter by a degree and richer than it would be cooler and poorer.  This is particularly true since sources like an Inconvenient Truth wildly exaggerate the negative effects of global warming.  There is no evidence tornadoes or hurricanes or disease or extinction are increasing as the world warms, and man-made warming advocates generally ignore any potential positive effects of warming.  As to rising sea levels, the IPCC predicts only a foot and a half of sea level rise even with 4 or more degrees of warming.  Sea level rise from a half to one degree of warming would be measured at most in inches.

OK, so that was more than 60 seconds.  But it is a lot less than 80 pages.  There is a lot of complexity behind every one of these statements.  If you are intrigued, or at least before you accuse me of missing something critical, see my longer paper on global warming skepticism first, where all these issues and much more (yes, including tree rings and cosmic rays) are discussed in more depth.

The table of contents for the rest of this paper, . 4A Layman's Guide to Anthropogenic Global Warming (AGW) is here.  Free pdf of this Climate Skepticism paper is here and print version is sold at cost here

I will not even try do full justice here to the basic theory
of AGW theory.  I highly encourage you to check out RealClimate.org.  This is probably
the premier site of strong AGW believers and I really would hate to see AGW
skeptics become like 9/11 conspiracists, spending their time only on
like-minded sites in some weird echo chamber. 

If you are reading this, you probably know that CO2 is what
is called a greenhouse gas.  This means that it can temporarily absorb
radiation from the Earth, slowing its return to space and thereby heating the
troposphere (the lower 10KM of the atmosphere) which in turn can heat up the
Earth's surface.  You probably also know that CO2 is not the only
greenhouse gas, and that water vapor, for example, is actually a much stronger
and more prevalent greenhouse gas.   

It is important to understand that the greenhouse gas effect
is well-understood in the laboratory.  No one really disagrees that, all
other effects held constant in a laboratory, CO2 will absorb certain
wavelengths of reflected sunlight.   What may or may not be
well-understood, depending on your point of view, is how this translates to the
actual conditions in our chaotic climate.  Does this effect dominate all
other climate effects, or is it trivial compared to other forces at work?
Does this greenhouse effect lead to runaway, accelerating change, or are there
opposing forces that tend to bring the climate back in balance?  These are
hugely complex questions, and scientists are a long way from answering them
empirically.

But wait, that can't be right -- scientists seem so
sure!  Well, some scientists, particularly those close to microphones,
seem sure.  Their proof usually follows one or both of these paths:

1. Some scientists argue that they believe they have
        accounted for all the potential natural causes, or "forcings," in the
        climate that might cause the warming we have observed over the last century,
        and they believe these natural forcings are not enough to explain recent
        temperature increases, so therefore the changes must be due to man.
        This seems logical, until I restate their logic this way:  "the
        warming must be due to man because we can't think of anything else it
        could be." 
2. Scientists have created complicated models to predict
        future climate behavior.  They argue that their models show man-made
        CO2 causing most 20^th century warming.  Again this sounds good,
        until one understands that when these models were first run, they were
        terrible at explaining history.  Since these first runs, scientists
        have tweaked the models until they match historical data better.  So,
        in effect, they are saying that manmade CO2 is the cause of historical
        warming because the models they tweaked to match history"¦ are very good at
        matching history; and because the models they programmed with CO2 as the
        major driver of climate show that"¦CO2 is the major driver of
        climate.  We will see a lot of such circular analysis in later
        chapters.

The best evidence we could expect to find (lacking a second
identical Earth we can use as a control in an experiment) is to find a historic
correlation between temperature and CO2 that is stronger than the correlation
between temperature and anything else (and of course, even this would not imply
causation).  There is a lot of argument whether we have that or not, a
topic I will cover in the next chapter.  Of course, the lack of unequivocal
evidence at this point does not make the AGW theory wrong, just still"¦
theoretical.   

Before we get to the historical evidence, though, there may
be a few other facts about CO2 and warming that you don't know:

• CO2 is a really, really small part of the atmosphere.
       Currently CO2 makes up about 0.0378% of the atmosphere, up from an
       estimated 0.0280% before the industrial revolution.  (Just to give an
       idea of scale, if you were flying from Los Angeles to New York City,
       traveling 0.0378% of the distance would not even get you off the runway at
       LAX.  AGW advocates are arguing that a CO2 concentration increase of
       0.009% has heated the world over a half a degree C.
• The maximum warming should, by greenhouse gas theories,
       occur in the troposphere (the first 10km or so of atmosphere).
       Global warming theory strongly predicts that the warming in the
       troposphere should be higher than warming at the ground.  We will see
       later that the opposite is actually occurring.
• The radiated energy returning to space consists of a wide
       spectrum of wavelengths.  Only a few of these wavelengths are
       absorbed by CO2.  Once these few wavelengths are fully absorbed,
       additional CO2 in the atmosphere has no effect whatsoever.  Also,
       these absorbed frequencies overlap with the absorption of other gasses,
       like water, which further lessens the incremental effect of extra CO2.

What does this mean?  In
effect, the warming effect of CO2 is a diminishing return relationship.
The first increase of, say, 100 parts per million (ppm) in the atmosphere has a
greater effect than the next 100 ppm, and so on until increased CO2 has
essentially no effect at all. 

I once bought a house that had
fuchsia walls in the kitchen and family room (really).  I spent all night
painting the rooms with a coat of white paint, and when I was done, I found
that some of the  fuchsia still showed through the white paint, making it
kind of light pink.  A second coat of white made the wall nearly perfectly
white.  The effects of CO2 in the atmosphere are similar, with the first
"coat" making for the most warming and later "coats" having much less effect
but still adding a bit.  At some point, the wall is white and more coats
have no effect. 

This relationship of CO2 to warming
is usually called sensitivity, and is often expressed as the number of degrees
of global warming that would result from a doubling in global temperature.

There are lots of values floating
around out there for sensitivity, but a preponderance (I won't say consensus)
seem to center on an increase of one degree C for a doubling of CO2 levels from
the pre-industrial figure of about 280ppm.  Note that you will see numbers
much higher than this, but these generally include feedback loops, which we
will get to later.  Without feedbacks, 0.5 to maybe 1.5 degrees seems like
a fairly well accepted number for sensitivity, though there are people on both
side of this range.

Luboš
Motl provides a handy approximation of the diminishing return effect from
CO2 concentration on temperature.  I have taken his approximation and
graphed it below.

This is a very crude approximation,
but the shape of the curve is generally correct (if you exclude feedbacks,
which we will discuss in MUCH more depth later).   Other more
sophisticated approximations generally show the initial curve less steep, and
the asymptote less pronounced.  Never-the-less, it is generally accepted
by most all climate scientists that, in the absence of feedbacks, future
increases in atmospheric CO2 will have less effect on world temperature than
past increases, and that there is a cap (in this chart around 1.5 degrees C) on
the total potential warming.

Note that this is much smaller than
you will see in print.  The key is in "feedbacks" or secondary effects
that accelerate or slow warming.  We will discuss these in more depth
later, but typically AGW supporters believe these will triple the sensitivity
numbers, so a non-feedback sensitivity of one degree would be tripled to three
degrees.  Remember, though, these three points:

· Warming from CO2 is a diminishing return, such that future CO2 increases
has less effect than past CO2 increases

· In the absence of feedback, a doubling of CO2 might increase
temperatures one degree C

· In the absence of feedback, the total temperature increase from future
CO2 increases is capped, maybe as low as 1-1.5 degrees C.

The table of contents for the rest of this paper, . 4A Layman's Guide to Anthropogenic Global Warming (AGW) is here.  Free pdf of this Climate Skepticism paper is here and print version is sold at cost here

The open comment thread for this paper can be found here. 

The table of contents for the rest of this paper, . 4A Layman's Guide to Anthropogenic Global Warming (AGW) is here.  Free pdf of this Climate Skepticism paper is here and print version is sold at cost here

We have gotten well into this paper, and we still have not
discussed what is perhaps the most problematic aspect of AGW research:
the computer models.

If an economist came up with a computer model that he claimed could predict
the market value of every house in the world in the year 2106 within $1,000,
would you believe him?  No, you would say he was nuts -- there is way too
much uncertainty and complexity.  Climate, of course, is not the same as
housing prices.  It is in fact, much, much more complex and more difficult
to predict.  There is nothing wrong with trying to predict the complex and
chaotic.  But there is a certain sense of hubris in believing that one has
succeeded with the kind of 95% certainty figures used by the IPCC.

All climate forecasting models are created by a pretty insular and
incestuous climate science community that seems to compete to see who can come
up with the most dire forecast.  Certainly there are financial incentives
to be as aggressive as possible in forecasting climate change, since funding
dollars tend to get channeled to those who are the most dramatic.
The global warming community spends a lot of time with ad hominem attacks
on skeptics, usually accusing them of being in the pay of oil and power
companies, but they all know that their own funding in turn would dry up
rapidly if they were to show any bit of skepticism in their own work.

The details of these models is beyond the scope of this paper.
However, it is important to understand how they work in broad outlines.

The modelers begin with certain assumptions about climate that they build
into the model.  For example, the computers themselves don't somehow
decide if CO2 is a more important forcing on the climate than solar activity "“
the modelers, by the assumptions the feed into the model, decide these
things.  The models return the result that CO2 is the most important
driver of climate in the coming century because their programmers built them
with that assumption, not because the model somehow sorts through different
inputs and comes up with the key drivers on its own.

Because the models have been built to test man's possible impact on the
climate via greenhouse gas emissions, they begin with an econometric forecast
of world economic growth, and, based upon assumptions about fuel sources and
efficiencies, they convert this economic growth into emissions forecasts.
The models generally contain subroutines that calculate, again based upon a
variety of assumptions, how man-made CO2 plus other inputs will change the
atmospheric CO2 concentration.  Then, via assumptions about climate
sensitivity to CO2 and various feedback loops programmed in, the models will
create forecasts of temperatures, precipitation, etc.  These models,
depending on their complexity, will show regional variations in many of these
variables.  Finally, the models are tuned so that they better match
history, in theory making them more accurate for the future.

One should note that while the IPCC asked modelers to look at a series of
different cases, the only substantial difference between these cases is the
volume of CO2 and other greenhouse gasses produced.  In other words, the
only sensitivity the IPCC seriously modeled was on levels of CO2.  No
other contingency "“ e.g. potential variations in global temperature sensitivity
to CO2, solar output, land use "“ were considered.  This should give you an
idea of how hard-wired the anthropogenic causation is in the IPCC process.

In this section, I will begin by discussing the models' basic assumptions
about the climate.  I will then discuss the econometric forecasts they are
founded on, the assumptions about CO2 sensitivity and feedback processes, and
finally model tuning and their ability to match history.

The Dangers in Modeling Complex Systems

At any one time, thousands of people are being paid literally millions of
dollars on Wall Street to try to model the behavior of various stock indices
and commodity prices.  The total brain power and money power thrown over
the last 50 years at trying to build an accurate predictive model for financial
markets literally dwarfs, by a factor of 100 or more, the cumulative resources
spent to date on long-term climate modeling.  Financial markets are
incredibly complex, and they are driven by hundreds of variables.
Interest rates, corporate profits, loan default rates, mortgage refinance
rates, real estate prices, GDP growth, exchange rates, etc. all tend to drive
the behavior of financial markets.  And no one has cracked the code.
Sure, some people have built successful short-term trading models, but people
have mostly lost their shirts when they have tried to make long-term bets based
on computer financial models that beautifully matched history but failed to
accurately predict the future.

How is it possible that a model that accurately represents the past fails to
accurately predict the future?  Financial modelers, like climate modelers,
look to history in building their models.  Again, like climate modelers,
they rely both on theory (e.g. higher interest rates should generally mean
lower stock prices) as well as observed correlations in the historic data
set.  The problem they meet, the problem that every modeler meets but most
especially the climate modeler, is that while it is easy to use various
analysis tools to find correlations in the data, there is often nothing that
will tell you if there is really a causal relationship, and which way the
causality runs. For example, one might observe that interest rates and exchange
rates move together.  Are interest rate changes leading to exchange rate
adjustments, or vice versa?  Or, in fact, are they both caused by a third
variable?  Or is their observed correlation merely coincidence?

It was once observed that if an old AFL football team wins the Superbowl, a
bear market will ensue on Wall Street in the next year, while an NFL team
victory presaged a bull market.  As of 1997, this correlation held for 28
of the last 31 years, a far better prediction record than that of any Wall
Street analyst.  But of course this correlation was spurious, and in the
next 4 years it was wrong every time.  Had someone built a financial model
on this indicator, it would have looked great when he ran it against history,
but he would have lost his shirt using it. 

Want a better prediction record?  For seventeen straight US
presidential election cycles, from 1936 to 2000, the winner of the election was
accurately predicted by"¦the Washington Redskins.  In particular, if the
Redskins won their last home game before the election, the party that occupies
the White House holds it in the election.  Otherwise, if the Redskins
lose, the opposition party wins.  Seventeen in a row!  R-squared of
one!  Success against odds of 131,072:1 of guessing all 17 right.
But of course, the input was spurious, and in 2004, soon after this
relationship made the rounds of the Internet, the algorithm failed.

This is why we spent so much time in the previous chapter on evaluating
historic correlations between CO2 and temperature.  Because the models are
built on an assumption that not only is temperature strongly correlated with
CO2, but that temperature is historically highly stable without this outside
anthropogenic forcing.  If there are problems with this assumed causation,
which we saw there are, then there in turn are major inherent problems with the
models themselves.   As climate scientist Syun-Ichi Akasofu of the
International Arctic Research Center at University of Alaska Fairbanks wrote:

The computers are "taught" that the temperature
rise during the last hundred years is due mostly to the greenhouse effect. If
the truth is that only about 10% of the present warming is caused by the
greenhouse effect, the computer code must be rewritten

Do Model Outputs Constitute Scientific Proof?

Remember what I said earlier:  The models produce the result that there
will be a lot of anthropogenic global warming in the future because they are
programmed to reach this result.  In the media, the models are used as a
sort of scientific money laundering scheme.  In money laundering, cash
from illegal origins (such as smuggling narcotics) is fed into a business that
then repays the money back to the criminal as a salary or consulting fee or
some other type of seemingly legitimate transaction.  The money he gets
back is exactly the same money, but instead of just appearing out of nowhere, it
now has a paper-trail and appears more legitimate.  The money has been
laundered.

In the same way, assumptions of dubious quality or certainty that presuppose
AGW beyond the bounds of anything we have see historically are plugged into the
models, and, shazam, the models say that there will be a lot of anthropogenic
global warming.  These dubious assumptions, which are pulled out of thin
air, are laundered by being passed through these complex black boxes we call
climate models and suddenly the results are somehow scientific proof of
AGW.  The quality hasn't changed, but the paper trail looks better, at
least in the press.  The assumptions begin as guesses of dubious quality
and come out laundered at "settled science."  Climate
Scientists Garth Paltridge wrote:

It needs to be understood that any reasonable
simulation even of present climate requires computer models to be tuned. They contain
parameters (that is, pieces of input information) whose numerical values are
selected primarily to give the right answer about today's climate rather than
because of some actual measurement. This was particularly so in the
mid-eighties. The problem with tuning is that it makes any prediction of
conditions different from those of the present far less believable. Even today
the disease of "tuneable parameters" is still rampant in climate
models, although fairly well hidden and not much spoken of in polite society.
The scientifically-inclined reader might try sometime asking a climate
researcher just how many such parameters there are in his or her latest model.
The reader will find there are apparently lots of reasons why such a question
is ridiculous, or if not ridiculous then irrelevant, and if not irrelevant then
unimportant. Certainly the enquirer will come away having been made to feel
foolish.

Econometrics and
CO2 Forecasts

The IPCC has never been able to choose a particular climate model it thinks
is best.  Instead, it aggregates ten or twelve of them and averages their
results, hoping that if there are errors in the climate models, they will
average out somehow (forgetting that systematic errors don't average out, as we
discussed earlier in the context of historic temperature
reconstructions).  The one thing the IPCC does do to bring some order to
all this is to establish baseline econometric and emissions scenarios for all
the teams to feed into the front end of their models.  That way, for a given
forecast case, they know variation in model output is due to differing
climate-related assumptions rather than differing economic assumptions.

But a funny thing happens when one tries to make an economic growth forecast
for 100-year periods, as the IPCC has: Very small changes in assumptions make
enormous differences.  Here is a simple example.  An economy that
grows by 3% per year will be 19x larger in 100 years.  However, if that
economy were to grow instead by 4% rather than 3%, it will be 51x larger in 100
years.  So a change in the growth rate by one percentage point yields a
final size nearly 2.7 times larger.   The same is true with
forecasting CO2 growth "“ a very small change in assumptions can lead to very
large differences in absolute production.

After release of the 3^rd IPCC report in 2001, researchers Ian
Castles, formerly the head of Australia's national office of statistics, and
David Henderson of the Westminster Business School and formerly the chief
economist of the OECD, decided to scrutinize
the IPCC's economic assumptions.  They found that the IPCC had made a
fundamental mistake in crafting their econometrics, one that caused all of
their economic growth estimates (and therefore estimates of CO2 production) to
be grossly overestimated.  Based on the IPCC assumptions, South Africa
ends up with a GDP per capita far in excess of the United States by the year
2100.  Incredibly, the IPCC numbers imply that Algeria, Argentina, Libya,
Turkey, and North Korea will all pass the US in per capita income by the end of
the century.

Beyond making it clear that there is an element of the absurd in the IPCC's
economic forecasting approach, these errors tend to inflate CO2 forecasts in
two ways.  First, CO2 forecasts are raised because, in the models, larger
economies produce more CO2.  Second, though, the models assume different
rates for CO2 production per unit of GDP for each country.  Most of the
countries the IPCC shows growing so fast "“ Algeria, South Africa, Libya, North
Korea, etc. "“ have lower than average CO2 efficiencies (i.e. higher than
average CO2 production per unit of GDP), so excess growth assumptions in these
countries has a disproportionate impact on projected CO2 emissions.  By
the way, it would be interesting to see if the IPCC is using marginal rather
than average rates.  For example, France has a very low average rate of
CO2 per unit of GDP because of its nukes, but its marginal growth is met mostly
with fossil fuels.

I can't say whether these same mistakes exist in the 2007 4^th
Assessment.  However, since the IPCC flatly rejected Castles and
Henderson's critique, it is likely the same methodology was used in 2007 as in
2001.  For example, here are the CO2 emissions forecasts from the 4^th
assessment "“ notice most all of them have a step-change increase in slope
between history and the future.  Just look at the jump across the dotted
line in lead case A1B, and several are even steeper.

So what does this mean?  Remember, small changes in growth rate make
big differences in end values.  For example, below are the IPCC fourth
assessment results for CO2 concentration.  If CO2 concentrations were to
increase at about the same rate as they are today, we would expect an end value
in 2100 of between 520 and 570 ppm, as opposed to the IPCC numbers below where
the projection mean is over 800 in 2100.  The difference is in large part
in the economic growth forecasts. 

Since it is not at all clear that the IPCC has improved its forecasting
methodology over the past years, it is instructive as one final exercise to go
back to the 1995 emissions scenarios in the 2^nd assessment.
Though the scale is hard to read, one thing is clear "“ only 10 years later we
are well below most of the forecasts, including the lead forecast is92a (this
over-forecasting has nothing to do with Kyoto, the treaty's impact has been
negligible, as will be discussed later).  One can be assured that if the
forecasts are already overstated after 10 years, they will be grossly
overstated in 100.

Climate Sensitivity
and the Role of Positive Feedbacks

As discussed earlier, climate sensitivity generally refers to the expected
reaction of global temperatures to a arbitrary change in atmospheric CO2
concentration.  In normal usage, it is usually stated as degrees Celsius
of global warming from a doubling in CO2 concentrations from pre-industrial
levels (approx 280 ppm to 560 ppm).  The IPCC and most AGW supporters put
this number at about 3.5 to 4.0 degrees C. 

But wait "“ earlier I said the number was probably more like 1.0C, and that
it was a diminishing return.  Why the difference?  Well, it has to do
with something called feedback effects.

Before I get into these, let's think about a climate sensitivity of 4
degrees C, just from a historical standpoint.  According to the IPCC, CO2
has increased by about 100ppm since 1880, which is about 36% of the way to a
doubling.  Over this same time period, global temperatures have increased
about 0.7C. Since not even the most aggressive AGW supporter will attribute all
of this rise to CO2 levels, let's be generous and credit CO2 with 0.5C.
So if we are 36% of the way to a doubling, and giving CO2 credit for 0.5
degrees, this implies that the sensitivity is probably not more than 1.4
degrees C.  And we only get a number this high if we assume a linear
relationship "“ remember that CO2 and temperature are a diminishing return
relation (chart at right), so future CO2 has less impact on temperature than
past CO2, so 1.4 would be at the high end.  In fact, using the logarithmic
relationship we saw before, 0.5 degrees over 36% of the doubling would imply a
sensitivity around 1.0.  So, based on history, we might expect at worst
another 0.5C from warming over the next century. 

Most AGW supporters would argue that the observed sensitivity over the last
30 years has been suppressed by dimming/sulfate aerosols.  However, to get
a sensitivity of 4.0, one would have to assume that without dimming, actual
warming would have been about 2.0C.  This means that for the number 4.0 to
be right,

1. Absolutely nothing else other than CO2 has been causing warming in the
last 50 years AND

2. Sulfate aerosols had to have suppressed 75% of the warming, or about
1.5C, numbers far larger than I have seen anyone suggest.  Remember that
the IPCC classifies our understanding of this cooling effect, if any, as "low"

But in fact, even the IPCC itself admits that its models assume higher
sensitivity than the historically observed sensitivity.  According to the
fourth IPCC report, a number of studies have tried to get at the sensitivity
historically (going back to periods where SO2 does not cloud the picture).
  Basically, their methodology is not much different in concept than
the back of the envelope calculations I made above.

These are shown in a) below, which shows a probability distribution of what
sensitivity is (IPCC4 p. 798). Note many of the highest probability values of
these studies are between 1 and 2.  Also note that since CO2 content is,
as the IPCC has argued, higher than it has been in recorded history, any
sensitivities calculated on historical data should be high vs. the sensitivity
going forward.  Now, note that graph c) shows how a number of the climate
models calculate sensitivity.  You can see that their most likely values
are consistently higher than any of the historical studies from actual
data.  This means that the climate models are essentially throwing out
historical experience and assuming that sensitivity is 1.5 to 2 times higher
going forward, despite the fact a diminishing return relationship says it
should be lower.

Sensitivity, based on History

Sensitivity that is built into the models  (Sorry, I still have no idea
what "constrained by climatology" means, but the text of the report makes it clear
that these sensitivities popped out of climate models

So how do these models get to such high sensitivities?  The answer, as
I have mentioned, is positive feedback.

Let me take a minute to discuss positive feedbacks.  This is something
I know a fair amount about, since my specialization at school in mechanical
engineering was in control theory and feedback processes.  Negative
feedback means that when you disturb an object or system in some way, forces
tend to counteract this disturbance.  Positive feedback means that the
forces at work tend to reinforce or magnify a disturbance.

You can think of negative feedback as a ball sitting in the bottom of a
bowl.  Flick the ball in any direction, and the sides of the bowl,
gravity, and friction will tend to bring the ball back to rest in the center of
the bowl.  Positive feedback is a ball balanced on the pointy tip of a
mountain.  Flick the ball, and it will start rolling faster and faster
down the mountain, and end up a long way away from where it started with only a
small initial flick.

Almost every process you can think of in nature operates by negative
feedback.  Roll a ball, and eventually friction and wind resistance bring
it to a stop.  There is a good reason for this.  Positive feedback
breeds instability, and processes that operate by positive feedback are
dangerous, and usually end up in extreme states.  These processes tend to
"run away."   I can illustrate this with an example:
Nuclear fission is a positive feedback process.  A high energy neutron
causes the fission reaction, which produces multiple high energy neutrons that
can cause more fission.  It is a runaway process, and it is dangerous and
unstable.  We should be happy there are not more positive feedback
processes on our planet.

Since negative feedback processes are much more common, and since positive
feedback processes almost never yield a stable system, scientists assume that
processes they meet are negative feedback until proven otherwise.  Except
in climate, it seems, where everyone assumes positive feedback is common.

In global warming models, water vapor plays a key role as both a positive
and a negative feedback loop to climate change.  Water vapor is a far more
powerful greenhouse gas than CO2, so its potential strength as a feedback
mechanism is high.  Water comes into play because CO2 driven warming will
put more water vapor in the atmosphere, because greater heat will vaporize more
water.  If this extra vapor shows up as more humid clear air, then this in
turn will cause more warming as the extra water vapor absorbs more energy and
accelerates warming.  However, if this extra water vapor shows up as
clouds, the cloud cover will tend to reflect energy back into space and retard
temperature growth. 

Which will happen?  Well, nobody knows.  The IPCC4 report admits
to not even knowing the sign of water's impact (e.g whether water is a
net positive or negative feedback) in these processes.  And this is just
one example of the many, many feedback loops that scientists are able to posit
but not prove. And climate scientists are coming up with numerous other
positive feedback loops.  As
one author put it:

Regardless, climate models are made interesting by
the inclusion of "positive feedbacks" (multiplier effects) so that a
small temperature increment expected from increasing atmospheric carbon dioxide
invokes large increases in water vapor, which seem to produce exponential
rather than logarithmic temperature response in the models. It appears to have
become something of a game to see who can add in the most creative feedback
mechanisms to produce the scariest warming scenarios from their models but
there remains no evidence the planet includes any such effects or behaves in a
similar manner.

Note that the majority of the warming in these models appears to be from
these feedback processes.  Though it is hard to pick it out exactly,
section 8.6 of the fourth IPCC report seems to imply these positive feedback
processes increase temperature 2 degrees for every one degree from CO2.
This explains how these models get from a sensitivity of CO2 alone of about 1.0
to 1.5 degrees to a sensitivity of 3.5 or more degrees "“ it's all in the
positive feedback.

So, is it reasonable to assume these feedback loops?
First, none have really been proven empirically, which does not of course
necessarily make them wrong. .  In our daily lives, we generally deal
with negative feedback:  inertia, wind resistance, friction are all negative
feedback processes.  If one knew nothing else, and had to guess if a
natural process was governed by negative or positive feedback, Occam's razor
would say bet on negative.   Also, we will observe in the next
section that when the models with these feedbacks were first run against
history, they produced far more warming than we have actually seen (remember
the analysis we started this section with "“ post-industrial warming implies
1-1.5 degrees sensitivity, not four).

Perhaps most damning is to ask, if this really is such a heavily positive
feedback process, what stops it?  Remember the chart from earlier (show
again at the right), showing the long-term relationship of CO2 and
warming.  Also remember that the data shows, and even AGW supporters
acknowledge, that temperature rises led CO2 rises by about 800 years.
Their explanation is that "something" caused the temperature to start
upwards.  This higher temperature, as it warmed the oceans, caused CO2 to
outgas from the oceans to the atmosphere.  Then, this new CO2 caused the
warming to increase further.  In other words, outgassing CO2 from the
oceans was a positive feedback to the initial temperature perturbation.
In turn, the IPCC argues there are various other positive feedbacks that
multiply the effect of the additional warming from the CO2.  This is
positive feedback layered on positive feedback.  It would be like barely
touching the accelerator and having the car start speeding out o f control.

So the question is, if global temperature is built on top of so many positive
feedbacks and multipliers, what stops temperature form rising once it
starts?  Why didn't the Earth become Venus in any of these events?
Because, for whatever else it means, the chart above is strong evidence that
temperature does not run away. 

I have seen two suggestions, neither of which is compelling.  The first
is that the oceans ran out of CO2 at some point.  But that makes no
sense.  We know that the oceans have far more CO2 than could ever be
liberated entirely to the atmosphere today, and besides,  the record above
seems to claim that CO2 in the atmosphere never really got above there it was
say in 1880.

The second suggestion is based on the diminishing return relationship of CO2
to temperature.  At some point, as I have emphasized many times, CO2's
ability to absorb infrared energy is saturated, and incremental quantities have
little effect.  But note in the IPCC chart above, CO2 on the long time
scale never gets as high as it is today.  If you argue that CO2's
absorption ability was saturated in earlier events, then you have to argue that
it is saturated today, and that incremental CO2 will have no further warming
effect, which AGW supporters are certainly NOT arguing.  Any theory based
on some unknown negative feedback has to deal with the same problem:  If
one argues that this negative feedback took over at the temperature peaks (in
black) doesn't one also have to argue that it should be taking over now at our
current temperature peak?  The pro-AGW argument seems to depend on an assumption
of negative feedbacks in the past that for some reason can't be expected to
operate now or in the future.  Why?

In fact, we really have not seen any evidence historically of these positive
feedback multipliers.  As I demonstrated at the beginning of this chapter,
even assigning as much as 0.5C of the 20^th century temperature
increase to CO2 only implies a sensitivity just over 1.0, which is about what
we would expect from CO2 alone with no feedbacks.  This is at the heart of
problems with AGW theory "“ There is no evidence that climate sensitivity to CO2
is anywhere near large enough to justify the scary scenarios spun by AGW
supporters nor to justify the draconian abatement policies they advocate.

My tendency is to conclude that in fact, positive feedbacks do not dominate
climate, just as they do not dominate any long-term stable system.  Yes,
certain effects can reasonably be said to amplify warming (ice albedo is
probably one of them) but there must exist negative feedbacks that tend to damp
out temperature movements.  Climate models will never be credible, and
will always overshoot, until they start building in these offsetting forcings.

Climate Models had
to be aggressively tweaked to match history

A funny thing happened when they first started running climate
models with high CO2 sensitivities in them against history:  The models
grossly over-predicted historic warming.  Again, remember our previous
analysis "“ historical warming implies a climate sensitivity between 1 and
1.5.  It is hard to make a model based on a 3.5 or higher sensitivity fit
that history.  So it is no surprise that one can see in the IPCC chart
below that the main model cases are already diverging in the first five years
of the forecast period from reality, just like the Superbowl predictors of the
stock market failed four years in a row.  If the models are already high
by 0.05 degree after five years, how much will they overshoot reality over 100
years?

In a large sense, this is why the global climate community has latched onto
the global dimming / aerosols hypothesis so quickly and so strongly.  The
possible presence of a man-made cooling element in the last half of the 20^th
century, even one that the IPCC fourth report ranks our understanding of as
"low," gives modelers a valuable way to explain why their models are
overstating history.  The aerosols hypothesis is valuable for two reasons:

· Since
SO2 is prevalent today, but is expected to go down in the future, it allows
modelers to forecast much higher warming and climate sensitivity in the future
than has been observed in the past.

· Our
very lack of understanding of the amount, if any, of such aerosol cooling is
actually an advantage, because it allows modelers to set the value of such
cooling at whatever value they need to make their models work

I know the last statement seems unfair, but in reading the IPCC and other
reports, it appears to me that aerosol cooling values are set in exactly this
way "“ as what we used to call a "plug" figure between actual temperatures and
model output.  While this may seem a chancy and fairly circular reasoning,
it makes sense for scientists because they trust their models.  They
really believe the outputs are correct, such that any deviation is not
attributed to their assumptions about CO2 or climate sensitivity, but to other
man-made effects.

But sulfates are not the only plug being used to try to make high
sensitivity models match a lower sensitivity past.  You can see this in
the diagram below from the fourth IPCC report.  This is their summary of
how their refined and tweaked models match history. 

The blue band is without anthropogenic effects.
The pink band is with anthropogenic effects, including warming CO2 and cooling
aerosols.  The black line is measured temperatures (smoothed out of
course).

You can see the pink band which represents the models with anthropogenic
effects really seems to be a lovely fit, which should make us all
nervous.  Climate is way too chaotic a beast to be able to model this
tightly.   In fact, given uncertainties and error bars on our
historical temperature measurements, climate scientists are probably trumpeting
a perfect fit here to the wrong data.  I am reminded again of a beautiful
model for presidential election results with a perfect multi-decadal fit based
on the outcome of NFL football games. 

But ignoring this suspiciously nice fit, take a look at the blue bar.
This is what the IPCC models think the climate would be doing without
anthropogenic effects (both warming CO2 and cooling sulfates, for
example).  With the peaked shape (which should actually be even more
pronounced if they had followed the mid-century temperature peak to its max)
they are saying there is some natural effect that is warming things until 1950
and then turns off and starts cooling, coincidently in the exact same year
that anthropogenic effects start taking off.  I challenge you to read
the IPCC assessment, all thousand or so pages, and find anywhere in that paper
where someone dares to say exactly what this natural effect was, or why it
turned off exactly in 1950. 

The reality is that this natural effect is another plug.  There is no
actual empirical data to back up the blue line (in fact, as we will see in the
alternate theories section, there is good empirical data that this blue band is
wrong).  Basically, climate scientists ran their models against history,
and found that even with their SO2 plug, they still didn't match well "“ they
were underestimating early century warming and over-estimating late century
warming.  Remember that the scientists believe their models and their
assumptions about a strong CO2 effect, so they have modeled the non-anthropogenic
effect by running their models, tuning them to historical actuals, and then
backing out the anthropogenic forcings to see what is left.  What is left,
the plug figure, is the blue line.

Already, the models used by the IPCC tend to overestimate past warming even
if all past warming is attributable to anthropogenic causes.  If
anthropogenic effects explain only a fraction of past warming, then the current
models are vastly overstated, good for stampeding the populous into otherwise
unpopular political control over the economy, but of diminished scientific
value.

The note I will leave you with is this:  Do not gain false confidence
in the global climate models when they show you charts that their outputs run
backwards closely match history.  This is an entirely circular argument,
because the models have been built, indeed forced, to match history, with
substantial plug figures added like SO2 effects and non-anthropogenic climate
trends, effects for which there are no empirical numbers.

The table of contents for the rest of this paper, . 4A Layman's Guide to Anthropogenic Global Warming (AGW) is here.  Free pdf of this Climate Skepticism paper is here and print version is sold at cost here

The open comment thread for this paper can be found here. 

The table of contents for the rest of this paper, . 4A Layman's Guide to Anthropogenic Global Warming (AGW) is here.  Free pdf of this Climate Skepticism paper is here and print version is sold at cost here

Solar Irradiance

If you walked into a room and found that it was too hot,
would you, as a first step:

1. Measure the air to find anomalies in the mix of gasses
2. Count the number of people in the room, to assess the effect
        of body heat on the room's temperature
3. Check the thermostat on the furnace

If you answered #3, sorry, but you can't join the
IPCC.  If you really want to irritate an AGW supporter, ask about the
sun.  To AGW supporters, only a Luddite would check the sun's output when
they could instead be obsessing over the increase in CO2 by 0.009% of the
atmosphere.

When they looked at the problem, the IPCC decided that over
the last 50 years, the sun has been irrelevant to warming.  Note that the
blue band in this chart (described in more detail in the last section), the
IPCC thinks that without man, the world would have cooled over the last 50
years:

Further, when they detailed different climate forcings, the
forcing from changing solar irradiance was a trivial rounding error (though
they had the good grace to mark their understanding of this as "low") meaning
the sun has very little effect vs. what the sun had in 1850 (in the Little Ice
Age!)

But it turns out, interestingly, that solar irradiance may be close to its
highest point in centuries.  Al Gore says that current global temperatures
are the highest they have been in 1000 years.  A new study by
the Institute of Astronomy in Zurich says that the "sun is more active now
than it has been at anytime in the previous 1,000 years."  Related?

Sunspots have been monitored on the Sun since 1610,
shortly after the invention of the telescope. They provide the longest-running direct
measurement of our star's activity.

The variation in sunspot numbers has revealed the
Sun's 11-year cycle of activity as well as other, longer-term changes.

In particular, it has been noted that between about
1645 and 1715, few sunspots were seen on the Sun's surface.

This period is called the Maunder Minimum after the
English astronomer who studied it.

It coincided with a spell of prolonged cold weather
often referred to as the "Little Ice Age". Solar scientists strongly
suspect there is a link between the two events - but the exact mechanism
remains elusive....

But the most striking feature, he says, is that
looking at the past 1,150 years the Sun has never been as active as it has been
during the past 60 years.

Over the past few hundred years, there has been a
steady increase in the numbers of sunspots, a trend that has accelerated in the
past century, just at the time when the Earth has been getting warmer.

The data suggests that changing solar activity is
influencing in some way the global climate causing the world to get warmer.

We can look at solar output over large time frames by
looking at the production of carbon-14 (less is produced in years of high solar
activity, and vice versa).  The analysis below used the ratio of oxygen
isotopes in the stalagmites to estimate the water temperature at the time they
were formed.  The result is an interesting correlation between solar
activity and a global temperature proxy over a long time-scale (Graph from Neff et al., 2001):

Over the last 1000 years, we see that (again using a
reversed scale of C14 as a proxy) solar activity is highly correlated with long
term temperature trends (I have used the pre-Mann chart, because while it may
over-emphasize the Medieval Warm Period, I still think such a period existed).

               
Solar Output
Anomaly                                                                      

              Temperature Anomaly

Look at the following reconstruction data by Judith Lean of
the Naval Research Library and charted from her data at NOAA by Junkscience.com
shows that interestingly, the sun's output does appear to be higher today than
they have been in many, perhaps hundreds of years

Would such increased activity be expected to result in
higher Earth temperatures?  I don't know, and there are some issues one
has to be careful with on this chart.  Most importantly the scaling:
While the shape of the curve looks a lot like the temperature trend over the
last 400 years, note that the entire variation from the low to the high point
is only about 0.25% "“ the scaling makes it look more dramatic.  Of course,
the same could be said for global temperature, where a half degree C
temperature increase on an absolute Kelvin scale would only be about 0.17%, so
an argument can be made that on a percentage basis, this change in irradiance
is about the same order of magnitude as our change in temperature.  A more
sophisticated comparison might say that since black body radiation is related
to absolute temperature to the fourth power, .25% increase in irradiance would
be expected to heat the Earth by .06%.

The chart on the above left compares the recent temperature
anomaly to solar irradiance, while the chart on the right compares it to CO2
concentrations.  Neither is a beautiful fit (and one may have to include
aerosols in either scenario to account for 1970's cooling) but solar irradiance
seems at least as good as that of CO2.  Remember, the IPCC shows
the world cooling due to solar effects during the same time the red solar
irradiance line is peaking. 

Recently Alexander et. al. in have done some very comprehensive
work relating solar irradiance and rainfall.  The study posits that one of
the reasons for less than perfect fit of sunspot and irradiance data with
temperature is that the Sun actually works on a 21 year cycle when the sunspot
cycle is combined with the cyclical wobble of the Suns motion through
space.  The study concluded:

The
Intergovernmental Panel on Climate Change (IPCC) (2001) dismisses the view that
solar activity has a meaningful influence on global climate. The basis for this
view is that variations in the receipt of solar activity are too small to
account for variations in the climatic responses. These variations were
determined from satellite and other observations. What the IPCC scientists
failed to appreciate is that changes in the level of solar radiation received
on earth are amenable to precise calculation. The variations are well in excess
of the IPCC value of +0,3 Wm"“2 quoted earlier.

One of the interesting things about solar output is that, if
it is really higher, we should see effects on other planets, not just on
Earth.  And, in fact, a lot of evidence has been pouring in over the last
5 years from astronomers (not climate guys) that the rest of the solar system
has been warming dramatically.

Take
Mars, for example.  Mar's ice caps have been melting and diminishing
since NASA's Mars Global Surveyor and Odyssey started to measure them around
2002. 

Changes in the red spot on Jupiter
seem to be a sign of warming temperatures.  And Neptunes moon Triton is
warming.  We have to be careful with how we draw conclusions on these
outer planets, since their "year" is so long, seasonal changes can last
decades. 

And
on Neptune:

As seen in Figure 1, Neptune has been getting
brighter since around 1980; furthermore, infrared measurements of the planet
since 1980 show that the planet has been warming steadily from 1980 to 2004. As
they say on Neptune, global warming has become an inconvenient truth. But with
no one to blame, Hammel and Lockwood explored how variations in the output of
the Sun might control variations in the brightness of Neptune.

Figure 1 (a) represents the corrected visible light from Neptune from 1950 to
2006; (b) shows the temperature anomalies of the Earth; (c) shows the total
solar irradiance as a percent variation by year; (d) shows the ultraviolet emission
from the Sun (Source: Hammel and Lockwood (2007)).

What would seem so simple statistically is
complicated by the degrees of freedom in the various time series which is
related to the serial correlation in the data (e.g., next year's value is
highly dependent on this year's value). Nonetheless, they find that the
correlation coefficient between solar irradiance and Neptune's brightness is
near 0.90 (1.00 is perfect). The same relationship is found between the Earth's
temperature anomalies and the solar output. Hammel and Lockwood note "In other
words, the Earth temperature values are as well correlated with solar
irradiance (r = 0.89) as they are with Neptune's blue brightness (|r| >
0.90), assuming a 10-year lag of the Neptune values." The temporal lag is
needed to account for the large mass of Neptune that would require years to
adjust to any changes in solar output.

Hammel and Lockwood conclude that "In summary, if
Neptune's atmosphere is indeed responding to some variation in solar activity
in a manner similar to that of the Earth albeit with a temporal lag" then
"Neptune may provide an independent (and extraterrestrial) locale for studies
of solar effects on planetary atmospheres."

More on the sun's
variance and climate change here.

Cosmic Rays

One of the problems with irradiance as a driver for climate
change is that though the changes seem to be fairly well correlated with the
temperature anomaly, many scientists think the magnitude is too small to
totally account for temperature changes.  It is ironic that AGW supporters
use this as a refutation of the sun's effect, since they have exactly the same
problem with CO2, and must posit huge positive feedback loops to justify their
forecasts. 

A second, newer theory has emerged as to a potential second
warming effect of solar output.  To understand it, we have to start with
clouds.  For those that don't live in a hot climate like I do here in
Phoenix, I will give everyone a bit of background "“ clouds cool things
off.  Ok, as with everything in climate, things are actually far more
complicated "“ high clouds can sometimes cause warming, and nighttime clouds can
actually slow cooling.  Never-the-less, in general, cloudcover cools things
off by blocking out and reflecting the sun's energy.

Clouds are in fact such a strong cooling force that is has
been estimated by several sources (Theodor Landscheidt, 1998) that having
clouds cover 1% more of the Earth's surface would cancel the heating effect of
a doubling of CO2.   In fact, it was one of my criticisms earlier
that AGW theory seems overly intent on finding positive feedback loops, while
not considering negative feedbacks seriously enough "“ one such potential
negative feedback is that on a warmer Earth, more water is evaporated into
clouds, in turn cooling things back off.

But recently, an interesting new theory on cloud formation
has emerged.  In short, it holds that cosmic rays, which are the high
energy particles that arrive at Earth from supernovas, spur cloud formation by
ionizing air molecules that act as seeds for water condensation and cloud
formation.  This sounds wild, but really no wilder than warming by a gas
(CO2) that makes up a near trivial portion of the atmosphere.  Like CO2 warming,
this effect has been observed in various laboratory chambers.  But is it
really a measurable driver of climate?

Henrik
Svensmark and Eigil Fris-Christensen looked at historic data on cloud cover
and cosmic ray incidence, from various measuring points.  Their data was
extended and refined by Shiva in 2005.

Cosmic rays
vs. CO2 detailed

So what changes cosmic ray flux to the Earth?  The
biggest influence is the sun.  When the sun's output is high, cosmic rays are
prevented from hitting the Earth, and vice versa.  So high solar activity
corresponds to low cosmic ray flux and therefore lower cloud formation and
higher temperatures. 

While the link between solar irradiance levels and warming
is pretty straight forward, the cosmic ray cloud formation proposition is still
in its infancy.  Those of us who criticize AGW supporters for running past
the evidence on CO2 should not make the same mistake on cosmic rays, and movies
such as The Global Warming Swindle have gone too far in portraying this
alternate theory as fact.

Man's Land Use

Recently, Roger Pielke has done a substantial amount of
research on a different type of anthropogenic forcing.  Specifically, he
has hypothesized that man's changing patterns of land use can be a substantial
driver of regional climate, including temperature and even more particularly,
precipitation.   For example, clearing relatively dry land and
replacing it with irrigated agriculture substantially changes to the local heat
balance,  not the least by increasing humidity.  Dr. Pielke explains
summarizes the consequences on his web site:

Humans are significantly altering
the global climate, but in a variety of diverse ways beyond the radiative
effect of carbon dioxide. The IPCC assessments have been too conservative in
recognizing the importance of these human climate forcings as they alter
regional and global climate. These assessments have also not communicated the
inability of the models to accurately forecast the spread of possibilities of
future climate. The forecasts, therefore, do not provide any skill in
quantifying the impact of different mitigation strategies on the actual climate
response
that would occur.

The table of contents for the rest of this paper, . 4A Layman's Guide to Anthropogenic Global Warming (AGW) is here.  Free pdf of this Climate Skepticism paper is here and print version is sold at cost here

The open comment thread for this paper can be found here. 

The table of contents for the rest of this paper, . 4A Layman's Guide to Anthropogenic Global Warming (AGW) is here.  Free pdf of this Climate Skepticism paper is here and print version is sold at cost here

As stated in the introduction, the purpose of this paper has
not been to provide a balanced portrayal of Anthropogenic Global Warming (AGW) theory; its purpose instead is to
provide a comprehensive overview of skeptic's concerns with AGW theory.
However, the issues raised here are not necessarily new, and AGW supporters
have attempted to address many of them. 

The New
Scientist, a fairly strong and reliable voice for advocacy of anthropogenic
global warming theory, recently published its response to what it calls 26
myths about global warming, many of these "myths" being correlated loosely with
skeptics concerns about AGW theory as outlined in this paper.  Walking
through their points seems a reasonable way to entertain a rebuttal to the
skeptic's position.  Each of these has a link to the New Scientist article
in question.  I have tried to summarize the position with a quote, shown
in italics.  My response to each then follows.

Before I get into these 20 myths, note that many of the key
skeptic's questions are neatly avoided.   While the magazine gives
itself certain softball questions, it does not attempt to take on skeptics
questions such as:

• Isn't warming from CO2 a diminishing return, such that each 10ppm of CO2
  has less warming effect than the last 10 ppm?
• Isn't warming from CO2 asymptotic, such that total warming from CO2 is
  capped?
• Isn't 2/3 or more of the future warming in IPCC forecasts due to
  positive feedback effects that tend to be rare in stable systems and that even
  the IPCC admits are poorly understood?
• Aren't there a lot of problems with ground-based temperature measurements?
• Aren't the historical proxies for temperature diverging from
  measurements, such that the IPCC actually dropped many of the recent proxy
  measurements to hide this result?

There are many others, but we can get at them tangentially
through dealing with the 20 "myths" below

"¢ Human
CO₂ emissions are too tiny to matter

So what's going on? It is true that human
emissions of CO₂ are small compared with natural sources. But the
fact that CO₂ levels have remained steady until very recently shows
that natural emissions are usually balanced by natural absorptions. Now
slightly more CO₂ must be entering the atmosphere than is being
soaked up by carbon "sinks".

Though I do know that some skeptics will claim that man can't be changing
world CO2 levels, I don't believe I even tried to make that claim in this paper.

The more salient point in
asking whether human CO2 emissions are too tiny to matter is to ask whether the
change in composition of the atmosphere of 0.009% by human activities is
substantial enough to affect world climate in any important way, particularly
when the portion being increased, CO2, is a relatively weak greenhouse gas vs.
other portions.

"¢ We
can't do anything about climate change

It is true that the action taken
so far, such as the Kyoto Protocol, will only have a marginal effect. The
protocol's authors have always described it as a first step. But even before it
came into effect in 2005, the protocol has triggered some profound thinking
among governments, corporations and citizens about their carbon footprint and
how to reduce it. Industrialized countries such as the UK are planning for
emissions reductions of 60% or more by mid-century.

This is a bit of a straw man.  Certainly to the extent
that man is causing climate change, men with enough will can do something about
it.  The question is whether the costs justify the avoided change "“ this
is a question that I have addressed sufficiently and won't revisit here.
However, I would like to comment on this:

We may find that once the
process has begun, the world loses its addiction to carbon fuels surprisingly quickly.
Natural scientists fear "tipping points" in the climate system. But there are
also tipping points in social, economic and political systems. Once under way,
things can happen fast"¦

This is a statement to which I both agree and disagree.  I am a technological
optimist, and so generally accept that world-changing technologies will
continue to spring from man's mind, and that the introduction of these changes
can be fast and their impact dramatic.  The only reason that I am a tad
skeptical about this statement is that the vast majority of strong AGW
adherents are technology pessimists, so it would be uncharacteristic for them
to take such a position.  Absent unimagined new technologies, change of
the type AGW supporters are hoping for is actually not a positive
feedback process as implied in this statement. Why is it that climate
scientists see so many positive feedback processes, when these are actually so
rare? In fact, most investment decisions, for example investments to reduce CO2
emissions, follow a diminishing return relationship.  Early investors
capture the low-hanging fruit, while each successive wave of investment offers
a lower return (here, in CO2 reduction) for each incremental dollar invested.

"¢ The
'hockey stick' graph has been proven wrong

Most researchers would agree that while the
original hockey stick can "“ and has "“ been improved in a number of ways, it was
not far off the mark. Most later temperature reconstructions fall within the
error bars of the original hockey stick. Some show far more variability leading
up to the 20^th century than the hockey stick, but none suggest that
it has been warmer at any time in the past 1000 years than in the last part of
the 20^th century.

No one statement by AGW supporters would do more to build my confidence in
their findings than to actually have someone say "the Mann hockey stick was a
deeply flawed analysis, and we have taken great pains to make sure the flaws identified
in Mann are not present in other historical reconstructions."  However,
when I see the statement above, I am left to wonder if any of the flaws in Mann
have actually been corrected in other works, or if systematic errors still
exist.  Since AGW supporters refuse to acknowledge flaws in Mann, it is
almost certain that these flaws still exist in the other analyses (therefore
making it unsurprising that new analyses show roughly the same results).
Remember that Mann was replaced by Biffra as lead author of this section of the
Fourth IPCC report, and it was Biffra who dropped 20-30 years of recent data
from his historical reconstruction when it did not show the result that he
wanted it to.

"¢ Chaotic
systems are not predictable

Getting reasonably accurate
predictions is a matter of choosing the right timescale: days in the case of
weather, decades in the case of climate.

Climate scientists sometimes
refer to the effects of chaos as intrinsic or unforced variability: the
unpredictable changes that arise from the dynamic interactions between the
oceans and atmosphere rather than being a result of "forcings" such
as changes in solar irradiance or greenhouse gases.

The crucial point is that
unforced variability occurs within a relatively narrow range. It is constrained
by the major factors influencing climate: it might make some winters bit a
warmer, for instance, but it cannot make winters warmer than summers

There are systems people who would both agree and disagree
with this statement.  The real study of chaotic systems is barely older
than the study of global warming, and most mathematicians would say that the
issue of long-term predictability of macro trends in chaotic systems is not
settled science.

However, one issue the statement overlooks is that even if
chaotic systems have some long-term order, at least when "viewed from a
distance," this does not mean that the drivers of those long-term trends can be
discerned by those of us standing in the chaos.  So while it may be
theoretically possible to predict long-scale climate changes, it may still be
impossible to discern the true drivers of these climate systems amidst the
chaos, making the long-term prediction problem moot.

Remember, no one has a thermometer that provides two readings "“ temperature
due to "natural" causes and temperature due to man-made forcings. 
The only argument one can make outside of a laboratory is to try to correlate
temperature changes to certain other variables, like CO2 level.  But in a
chaotic system, when thousands of variables may matter, and there are all kinds
of cross-dependencies between variables, definitively showing direct
correlation, much less causation, is very hard, possibly impossible. 
Remember, outside lab experiments, climate scientists main argument that CO2 is
causing current warming is "We have checked everything else it possibly could
be, and it wasn't those things, so it must be CO2."  In a chaotic system,
such a statement borders on hubris.

"¢ We
can't trust computer models of climate

Climate is average weather, and it can vary unpredictably
only within the limits set by major influences like the Sun and levels of
greenhouse gases in the atmosphere. We might not be able to say whether it will
rain at noon in a week's time, but we can be confident that the summers will be
hotter than winters for as long as the Earth's axis remains tilted.

The validity of models can be tested against
climate history. If they can predict the past (which the best models are pretty
good at) they are probably on the right track for predicting the future "“ and
indeed have successfully done so.

I hope that if you have learned anything from this paper, you already know
how to refute the statement above.  Climate models match history because
they have been tuned and tweaked and overridden to do so.  The fact that
they then can reproduce history is meaningless.  Even more, you should run
away quickly from anyone who makes this statement, because they are either
ignorant of what they are talking about or they are trying to sell you the
Brooklyn Bridge.

Finally, the claim is sometimes
made that if computer models were any good, people would be using them to
predict the stock market. Well, they are!

A lot of trading in the
financial markets is already carried out by computers. Many base their
decisions on fairly simple algorithms designed to exploit tiny profit margins,
but others rely on more sophisticated long-term models.

Sorry, but this is a facile and ignorant mis-interpretation of what
financial models are doing.  Yes, people are running long-term financial
models as part of a trading strategy, but these models feed into very
short-term trading decisions.  If you looked at the output from these long-term
models, you would see that they are changing constantly as new data flows
in.  There is an old joke about two campers who see a bear growling at
them.  One of them starts putting his tennis shoes on.  The other one
says to him "Why are you putting your shoes on?  You can't outrun that
bear."   His friend replied "I don't have to outrun the bear.  I
just have to outrun you."  Traders' long-term models work the same.
They don't actually expect them to be right, they just want them to be better,
based on current conditions, than other traders' models, then they can make
money.

"¢ They
predicted global cooling in the 1970s

Indeed they did"¦. However, Schneider soon
realised he had overestimated the cooling effect of aerosol pollution and
underestimated the effect of CO₂, meaning warming was more likely
than cooling in the long run"¦.

The calls for action to prevent further
human-induced global warming, by contrast, are based on an enormous body of
research by thousands of scientists over more than a century that has been
subjected to intense "“ and sometimes ferocious "“ scrutiny. According to the
latest IPCC report, it is more than
90% certain that the world is already warming as a result of human activity

We have already dealt with aerosols, and unlike many skeptics I have not
really held the 1970's global cooling panic against the climate
community.  The last paragraph is just circular.  Saying the IPCC is
90% sure does not answer the arguments about what skeptics feel the IPCC is
ignoring.

"¢ It's
been far warmer in the past, what's the big deal?

First of all, it is worth bearing in mind that
any data on global temperatures before about 150 years ago is an estimate, a
reconstruction based on second-hand evidence such as ice cores and isotopic
ratios. The evidence becomes sparser the further back we look, and its
interpretation often involves a set of assumptions. In other words, a fair
amount of guesswork.

This is hilarious.  What happened to their confidence in Mann and
1000-year temperature reconstructions just a few myths back?  But to
continue, the answer is basically yes, but:

The important question is what
is causing the current, rapid warming? We cannot dismiss it as natural
variation just because the planet has been warmer at various times in the past.
Many studies suggest it can only be explained by taking into account human
activity.

Nor does the fact that it has
been warmer in the past mean that future warming is nothing to worry about. The
sea level has been tens of metres higher during past warm periods, enough to
submerge most major cities around the world.

Here is why it matters "“ beyond the laboratory evidence of the greenhouse
effect, which tells us merely that there is an affect and not how strong it is,
the main evidence cited by AGW supporters for current warming being man-made is
to try to show that current warming is somehow unprecedented, and therefore
unlikely to be natural.  So it is odd here that AGW supporters simply
shrug their shoulders here and say that it is not important that current
warming be unprecedented.

"¢ It's
too cold where I live - warming will be great

This does not sound too bad, and for many people
it won't be. Wealthy individuals and countries will be able to adapt to most
short-term changes, whether it means buying an air conditioner or switching to
crops better suited to the changing climate. Rainfall will fall in
mid-latitudes but rise in high latitudes, and initially agricultural yields
will probably.  Some regions will suffer, though. Africa could be hardest
hit, with yields predicted to halve in some countries as early as 2020.

As global temperature climbs to 3°C above
present levels - which is likely
to happen before the end of this century if greenhouse emissions continue
unabated - the consequences will become increasingly severe. More than a third
of species face extinction. Agricultural yields will start to fall in many
parts of the world. Millions of people will be at risk from coastal flooding.
Heatwaves, droughts, floods and wildfires will take an ever greater toll.

I hope readers will accept that I am not exaggerating or constructing straw
men when I talk about the dire predictions by AGW supporters.  There is
nothing here that we have not dealt with earlier, except perhaps the
rainfall.  Of late, AGW supporters seem to have shifted to rainfall
(rather than sea level rise) as their lead scary topic.  Note, however,
that even the IPCC admits that it and all of its modelers really do not
understand (even a little bit) the effect of global warming on rainfall and
drought.  Logic says that with more water evaporated, while global warming
may cause now local draughts, overall rainfall should increase.  I would
bet any amount of money that lower economic growth due to aggressive CO2 abatement
will have a far more deleterious effect on worldwide agricultural yields than
global warming.

"¢ Global
warming is down to the Sun, not humans

So what role, if any, have solar fluctuations
had in recent temperature changes? While we can work out how Earth's orbit has
changed going back many millions of years, we have no first-hand record of the
changes in solar output associated with sunspots before the 20^th century.

It is true that sunspot records go back to the
17^th century, but sunspots actually block the Sun's radiation. It is
the smaller bright spots (faculae) that increase the Sun's output and these
were not recorded until more recently. The correlation between sunspots and
bright faculae is not perfect, so estimates of solar activity based on sunspot
records may be out by as much as 30%.

The other method of working out past solar
activity is to measure levels of carbon-14 and beryllium-10 in tree rings and
ice cores. These isotopes are formed when cosmic rays hit the atmosphere, and
higher sunspot activity is associated with increases in the solar wind that
deflect more galactic cosmic rays away from Earth. Yet again, though, the
correlation is not perfect. What is more, recent evidence suggests that the
deposition of beryllium-10 can
be affected by climate changes, making it even less reliable as a measure
of past solar activity.

This is again a pretty hilarious statement.  One could easily argue
that temperature and CO2 proxies have at least as much
uncertainty.  One wonders why AGW advocates do not seem as concerned about
the errors in the proxies they hold dear.  But anyway, to continue:

But even if solar forcing in the past was more
important than this estimate suggests, as some scientists think, there is no
correlation between solar activity and the strong warming during the past 40
years. Claims that this is the case have not stood up to scrutiny (pdf document).

Direct measurements of solar output since 1978
show a steady rise and fall over the 11-year sunspot cycle, but no upwards or downward trend .

Similarly, there is no trend in direct
measurements of the Sun's ultraviolet output and in cosmic rays. So for the
period for which we have direct, reliable records, the Earth has warmed
dramatically even though there has been no corresponding rise in any kind of
solar activity.

This is another you-study-my-study pissing match.  I am happy to admit
that our knowledge of the sun's changing impact on climate is poor, and that it
is hard to separate out this one effect in a chaotic system.  I refuse to
fall into the same scientific hubris as AGW supporters.  However, those
who think the sun has some contribution to warming are buttressed by the
knowledge that they are working with the main driver of climate, rather than a
secondary variable.

"¢ It's
all down to cosmic rays

There is no convincing evidence
that cosmic rays are a major factor determining cloud cover. The ionising of
air by cosmic rays will impart an electric charge to aerosols, which in theory
could encourage them to clump together to form particles large enough for cloud
droplets to form around, called "cloud condensation nuclei".

But cloud physicists say it has
yet to be shown that such clumping occurs. And even if it does, it seems
far-fetched to expect any great effect on the amount of clouds in the atmosphere.
Most of the atmosphere, even relatively clean marine air, has plenty of cloud
condensation nuclei already.

A series of attempts by
Svensmark to show an effect have come unstuck. Initially, Svensmark claimed
there was a correlation between cosmic ray intensity and satellite measurements
of total cloud cover since the 1980s "“ yet a correlation does not prove cause
and effect. It could equally well reflect changes in solar irradiance, which
inversely correlate with cosmic ray intensity.

I am starting to notice a trend here of making statements about competing
that could be applied equally well to AGW theory.  And what about all
those points they made above, reminding us over and over that CO2 greenhouse
theory works in the lab.  Now the lab is not good enough?

However, I would accept that the cosmic ray theory is pretty undeveloped and
not acceptably proven.  It has had a number of fits and starts.  Just
like CO2 greenhouse theory, the cosmic ray effect on climate can be reproduced
in the lab, but it is really hard to parse out its effects in the chaotic
climate.

"¢ CO₂
isn't the most important greenhouse gas

At some of these overlaps, the
atmosphere already absorbs 100% of radiation, meaning that adding more
greenhouse gases cannot increase absorption at these specific frequencies. For
other frequencies, only a small proportion is currently absorbed, so higher
levels of greenhouse gases do make a difference.

This means that when it comes to
the greenhouse effect, two plus two does not equal four.

Wow!  An AGW supporter actually said this in public.  This is to
our point that there is a diminishing return from incremental CO2 in the
atmosphere.  Of course, they say this in the context of trying to show why
water isn't as important as it might seem, but still, it's there

But the overall quantities of these other gases
are tiny. Even allowing for the relative strength of the effects, CO₂
is still responsible for two-thirds
of the additional warming caused by all the greenhouse gases emitted as a
result of human activity.

Water vapour will play a huge role in the
centuries to come, though. Climate models, backed by satellite
measurements, suggest that the amount of water vapour in the upper
troposphere (about 5 to 10 kilometres up) will double by the end of this
century as temperatures rise.

This will result in roughly twice as much
warming than if water vapour remained constant. Changes in clouds could lead to
even greater amplification of the warming or reduce it "“ there is great uncertainty
about this. What is certain is that, in the jargon of climate science, water
vapour is a feedback, but not a forcing.

Again, I am not getting into this, we covered it plenty in the paper.
When they say "CO2 is still responsible for two-thirds of the additional
warming" (and remember this is an output of their models, not any other
analysis)  what they really mean is that "our models that were programmed
to have CO2 drive the climate show that CO2 drives the climate."
Note that in a three paragraph answer about the effect of water vapor as
a climate feedback, only three words "“ "or reduce it" "“ acknowledge that it
might actually have a negative feedback effect, despite the fact that even the
IPCC includes cloud cover as a negative feedback.  They just don't want to
admit a negative feedback might even exist.

"¢ The
lower atmosphere is cooling, not warming

One study in Science
revealed errors in the way satellite data had been collected and interpreted.
For instance, the orbit of satellites gradually slows, which has to be taken
into account because it affects the time of day at which temperature recording
are taken. This problem was always recognised, but the corrections were given
the wrong sign (negative instead positive and vice versa).

A second study, also
in Science, looked at the weather balloon data. Measurements of the air
temperature during the day can be skewed if the instruments are heated by
sunlight. Over the years the makers of weather balloons had come up with better
methods of preventing or correcting for this effect, but because no one had
taken these improvements into account, the more accurate measurements appeared
to show daytime temperatures getting cooler.

The corrected temperature records show that
tropospheric temperatures are indeed rising at roughly the same rate as surface
temperatures. Or, as a 2006 report by the US Climate Change Science Program (pdf) puts
it: "For recent decades, all current atmospheric data sets now show
global-average warming that is similar to the surface warming." This one
appears settled.

There is still some ambiguity in the tropics,
where most measurements show the surface warming faster than the upper
troposphere, whereas the models predict faster warming of the atmosphere.
However, this is a minor discrepancy compared with cooling of the entire
troposphere and could just be due to the errors of margin inherent in both the
observations and the models.

First, observe absolutely ruthless efforts to apply corrections and
adjustments to any measurement that does not fit their theory, while blithely
accepting the surface temperature measurements that we showed can be really
unreliable.  Given the choice of focusing on managing satellite
temperatures up or surface temperature down, you can see which they
chose.   Second, note that this is another narrow one study
conclusion.  AGW supporters frequently cite single studies (conducted by
AGW supporters) that overturn skeptics arguments as having "settled" the
issue.  There are still many reasons to think that troposphere temperature
increases are less than surface increases.  Finally, even temperature
increases that were the same between the surface and the troposphere would be a
real problem for AGW theory.  The authors here act like this
surface-troposphere issue is a minor deal, but in fact if AGW theory is right,
the troposphere has to warm more, because that is where the extra heat
is being absorbed.  This is not at all settled. 

"¢ Antarctica
is getting cooler, not warmer, disproving global warming

It is clear that the Antarctic Peninsula, which juts
out from the mainland of Antarctica towards South America, has warmed
significantly. The continent's interior was thought to have warmed too, but in
2002 a new analysis of
records from 1966 to 2000 concluded that it has cooled overall"¦.

Climate models do not predict an evenly spread
warming of the whole planet: changes in wind patterns and ocean currents can
change the distribution of heat, leading to some parts warming much faster than
average, while others cool at first.

Agreed

"¢ The
oceans are cooling

Now the authors of the 2006 study have submitted a
correction (pdf format). It turns out that a fault in the software on some
of the floats led to some temperature measurements being associated with the
wrong depth.

Meanwhile, work by other teams suggests that the
past warmth of the oceans has been overestimated. The problem was due to
expendable sensors that are thrown overboard and take measurements as they
sink.

I never had heard the claim that the oceans were cooling, so it does not
surprise me that they are not.  However, it is again interesting the
amount of due diligence that AGW supporter put in to the correction of any
temperature measurement the might refute global warming, while blithely
accepting the atrocious condition and biases in ground-based temperature
measurement because, well, because these instruments are telling the story they
want to hear.

"¢ The
cooling after 1940 shows CO₂ does not cause warming

The mid-century cooling appears to have been
largely due to a high concentration of sulphate aerosols in the atmosphere,
emitted by industrial activities and volcanic
eruptions. Sulphate aerosols have a cooling effect on the climate because
they scatter light from the Sun, reflecting its
energy back out into space.

The rise in sulphate aerosols was largely due to
the increase in industrial activities at the end of the second world war. In
addition, the large eruption of Mount Agung in 1963 produced aerosols which cooled the
lower atmosphere by about 0.5°C, while solar activity levelled off after
increasing at the beginning of the century

I think I was pretty fair in discussing the aerosol cooling hypothesis in
this paper, though many would disagree with the above statement's certainty.

Climate models that take into account only
natural factors, such as solar activity and volcanic eruptions, do not
reproduce 20th century temperatures very well. If, however, the models include
human emissions, including greenhouse gases and aerosols, they accurately reproduce
the 1940 to 1970 dip in temperatures.

I hope readers who have made it this far can supply the refutation of this
point:  Wrong, wrong, wrong.  Climate models initially matched
history poorly.  Today they match well because they have been tweaked and
adjusted and forced to match.  They match because they are programmed to
match.  And, as we discussed, they match only because they make
ridiculously low assumptions for natural forcings, and assume all natural
forcings causing temperatures to rise in the first half of the century
magically reversed in 1950, though there is no good evidence for it. 

"¢ It
was warmer during the Medieval period, with vineyards in England

In the southern hemisphere, the picture is even
more mixed, with evidence of both warm and cool periods around this time. The
Medieval Warm Period may have been partly a regional phenomenon, with the
extremes reflecting a redistribution of heat around the planet rather than a
big overall rise in the average global temperature.

What is clear, both from the temperature
reconstructions and from independent evidence "“ such as the extent of the
recent melting of mountain glaciers "“ is that the planet has been warmer in the
past few decades than at any time during the medieval period. In fact, the
world may not have been so warm for 6000 or even 125,000 years (see Climate myths: It has been warmer in the past,
what's the big deal?).

What really matters, though, is not how warm it
is now, but how warm it is going to get in the future. Even the temperature
reconstructions that show the greatest variations in the past 1000 years suggest
up until the 1980s, average temperature changes remained within a narrow band
spanning 1ºC at most. Now we are climbing out of that band, and the latest IPCC report (pdf format) predicts a further rise of
0.5ºC by 2030 and a whopping 6.4ºC by 2100 in the worst case scenario.

We have covered this pretty well in this paper, so again I won't go back
into it, except to highlight a couple of things we can learn from this
statement.  First, note the hubris again "“ it is warmer today than in the
last 125,000 years.  I sure wish there was a way to bet on this "“ I would
have only a one in 125,000 chance of being wrong in betting against this
statement.  Second, note the use of the worst case scenarios.  For
2100, we don't get the best case or even the average case, we get the worst
case.  Can you name another branch of science where people do this?
Can you imagine, say, a group out to measure the speed of light.  They are
going to get some middle figure with an error band of some range.
Wouldn't you expect them to day that they found the speed of light to be
so-and-so, plus or minus an error of such-and-such size?  If they were
climate scientists, they would instead announce that they have found the speed
of light could be as large as Z, that being the highest possible figure in
their error band.

"¢ We
are simply recovering from the Little Ice Age

Yet while there is some evidence of cold
intervals in parts of the southern hemisphere during this time, they do not appear to
coincide with those in the northern hemisphere. Such findings suggest the Little
Ice Age may have been more of a regional phenomenon than a global one.

Solar radiation was probably lower at times
during this period, especially during a dip in solar activity called the
Maunder minimum around 1700, but models and temperature reconstructions suggest
this would have reduced average global temperatures by 0.4ºC at most.

The larger falls in temperature in Europe and
North American may have been due to changes in atmospheric circulation over the
North Atlantic, or in the Gulf Stream, or both, reducing heat transport from
the tropics (see Climate
change sceptics lose vital argument).

The warming after the so-called Little Ice Age
may reflect both an increase in solar activity and a redistribution of heat
around the planet. In particular, the increase in global temperature in the
first half of the 20^th century may have been largely due to an increase
in solar activity. The continued warming in recent decades, however, cannot be
explained by increases in solar radiation alone

Remember the graphs we showed earlier "“ the arctic proxies look like the
current warming is a straight linear increase from the 1700s to today.  In
fact, in the IPCC spaghetti graph showing all those historic reconstructions,
they all show a natural warming from the 18^th and 19^th
century through the 20^th.  Again, AGW supporters really need to
explain why they are so confident that this natural warming trend stopped in
1945 or so, exactly and coincidently at the exact same moment that man-made
forcings caused the world to continue to warm, coincidently at about the same
rate it was warming naturally earlier in the century.

"¢ Warming
will cause an ice age in Europe

Few scientists think there will
be a rapid shutdown of circulation. Most ocean models predict no more than a
slowdown, probably towards the end of the century. This could slow or even
reverse some of the warming due to human emissions of greenhouse gases, which
might even be welcome in an overheated Europe, but the continent is not likely
to get colder than it is at present.

A slowdown in circulation would
affect many parts of the world by disrupting global rainfall patterns. But
these effects will be insignificant compared with the much greater changes
global warming will cause

I already mentioned that this had been refuted pretty well

"¢ Ice
cores show CO₂ increases lag behind temperature rises, disproving
the link to global warming

It takes about 5000 years for an
ice age to end and, after the initial 800 year lag, temperature and CO₂
concentrations in the atmosphere rise together for a further 4200 years.

What seems to have happened at
the end of the recent ice ages is that some factor "“ most probably orbital
changes "“ caused a rise in temperature. This led to an increase in CO₂,
resulting in further warming that caused more CO₂ to be released and
so on: a positive feedback that amplified a small change in temperature. At
some point, the shrinking of the ice sheets further amplified the warming.

Models suggest that rising
greenhouse gases, including CO₂, explains about 40% of the warming
as the ice ages ended. The figure is uncertain because it depends on how the
extent of ice coverage changed over time, and there is no way to pin this down
precisely.

I was extremely happy to see that they at least tried to
address the issue I raised, ie is it really realistic to have a process
dominated by positive feedback, and if so, why doesn't it run away.  Their
answer:

Finally, if higher temperatures lead
to more CO₂ and more CO₂ leads to higher temperatures,
why doesn't this positive feedback lead to a runaway greenhouse effect? There
are various limiting factors that kick in, the most important being that
infrared radiation emitted by Earth increases exponentially with temperature,
so as long as some infrared can escape from the atmosphere, at some point heat
loss catches up with heat retention.

Which might make sense EXCEPT that they are claiming that
today's temperature and level of CO2 are higher than these historical levels,
so we are already higher than the level where they claim "heat loss catches up
with heat retention."  So either their answer is right, and there is a
strong compensating process which is not built into their models, or they are
wrong and they still need to explain what keeps a positive feedback dominated
process from running away.

"¢ Ice
cores show CO₂ rising as temperatures fell

There are some mismatches though. Besides lags
at the end of ice ages, cores taken from the ice overlying the famous
lake below Vostok in Antarctica seemed to show that about 120,000 years
ago, the temperature plummeted sharply while CO₂ levels remained high
for many thousands of years.

The question is whether this is real or just a
reflection of the problems with working out the age of the trapped air and with
deuterium as a temperature indicator. Many researchers are working on ways to
independently date the air and the ice, and to improve temperature
reconstructions based on relative deuterium content. One involves working out
what is called the deuterium excess by comparing the relative amounts of
deuterium and oxygen-18 in the ice.

The deuterium excess reflects the temperature at
the sea surface where the water that later fell as snow evaporated, rather than
the surface temperature where the snow fell. It helps to reveal whether
variations in the relative deuterium content of the ice are a result of water
coming from a different source region rather than changes in local temperature.

In 2001, researchers used the deuterium excess to correct for some of the
problems with the temperature record of the Vostok ice core. Their results produce
a much closer fit between temperature and CO₂ levels and reduces the
mismatch around 120,000 years ago to a few thousand years.

I did not really raise this issue, as even the most enthusiastic AGW
supporter does not tend to claim that CO2 drives all historic temperature
changes.  However, again, note the pattern "“ any historic data that does
not fit with AGW data typically is scrutinized and "corrected." 
Articles discussing flaws in methodology in gathering such data are quickly published.
Contrast this with the difficulty scientists have in questioning any data that
supports AGW theory.  As we saw earlier, the New Scientist still can't
bring itself to utter the words "the Mann hockey stick was flawed."
Neither could the IPCC, they just sort of dropped it, or buried it in the midst
of 12 others, without even saying why the analysis that was the centerpiece of
their last report was strangely missing.

"¢ Mars
and Pluto are warming too

The Sun's energy output has not increased since
direct measurements began in 1978. If increased solar output really was
responsible, we should be seeing warming on all the planets and their moons,
not just Mars and Pluto.

Our solar system has eight planets, three dwarf
planets and quite a few moons with at least a rudimentary atmosphere, and thus
a climate of sorts. Their climates will be affected by local factors such as
orbital variations, changes in reflectance (albedo) and even volcanic
eruptions, so it would not be surprising if several planets and moons turn out
to be warming at any one time.

I agree we have a lot to learn about this, and nothing at all is
settled.  However, we now have evidence from at least 5 other terrestrial bodies
that are warming at the same time the Earth is warming.  Why do AGW
supporters resist at least investigating further?

"¢ Many
leading scientists question climate change

Climate change sceptics sometimes claim that
many leading scientists question climate change. Well, it all depends on what
you mean by "many" and "leading". For instance, in April
2006, 60 "leading scientists" signed a letter urging Canada's
new prime minister to review his country's commitment to the Kyoto protocol.

This appears to be the biggest recent list of
sceptics. Yet many, if not most, of the 60 signatories are not actively engaged
in studying climate change: some are not scientists at all and at least 15 are
retired.

Compare that with the dozens of statements on
climate change from various scientific organisations around the world
representing tens of thousands of scientists, the consensus position
represented by the IPCC reports and the 11,000 signatories to a petition condemning the Bush administration's
stance on climate science.

I have carefully avoided the game of dueling scientific numbers.  As to
the claim that the skeptic list "are not actively engaged in studying
climate change: some are not scientists at all and at least 15 are retired" I
would be thrilled if AGW supporters held to this standard in making their own
numbers.  But, they manage to abandon this standard by the next paragraph,
when they claim the pro-AGW numbers, like the 11,000, are open to the same
criticism (since there are only 500-600 true climate scientists in the world,
vs. physicist, meteorologists, etc). 

"¢ It's
all a conspiracy

Now that there is a consensus, those whose
findings challenge the orthodoxy are always going have a tougher time
convincing their peers, as in any field of science. For this reason, there will
inevitably be pressure on scientists who challenge the consensus. But findings
or ideas that clash with the idea of human-induced global warming have not been
suppressed or ignored "“ far from it.

Journalists do have an interest in promoting
themselves (and their books), while their employers want to boost their
audience and sell advertising. Publicity helps with all these aims, but you get
far more publicity by challenging the mainstream view than by promoting it.
Which helps explain why so many sections of the media continue to publish or
broadcast the claims of deniers, regardless of their merit.

The notion of a "conspiracy" of course, is a useful straw man, implying
devious villains in the SPECTRE conference room planning the overthrow of the
world.   I won't argue the point again, except to encourage you to
watch the news with a critical eye, and decide for yourself.  However, just
to get you started, ask yourself if these events are signs of healthy, unbiased
science:

· A
group of AGW supporters are trying to get the British government to use force
to block the publication of a skeptical movie (the Global Warming Swindle)

· AGW
supporters in California have included skeptical scientists such as MIT's Dr.
Richard Lindzen as defendants in a law suit, asking that damages be paid by
people and companies whose public speech doesn't conform to AGW theory

· Many
AGW skeptics have been unable to get scientists who have published publicly
funded research to reveal their data and methodology for critique.
Freedom of Information Act (FOIA) requests have become a necessary tool of
climate skeptics.

· When
a group began photographing temperature measurement points to document the
shortcomings in historical surface temperature measurements, the NOAA pulled
the locations of its measurement stations off the Internet so that these US
citizens could no longer take pictures of and critique US government
installations.

· Scientists
who question AGW theory are equated by AGW supporters with Holocaust deniers.

"¢ Hurricane
Katrina was caused by global warming

More data is needed settle the issue. Some are
looking to natural records of past
hurricane activity in stalagmites, lake deposits and coral rubble. Others
are re-analysing existing databases. In February 2007, one such re-analysis
concluded that over the past two decades, hurricane intensity has increased
in the Atlantic but not in other parts of the world (pdf format).

Yet another complicating factor is that changes
in climate can also change the paths that tropical cyclones tend to take,
determining whether they remain over oceans or strike land.

What every one agrees on is that over the past
few decades there has been a huge rise in the number of people being killed or
injured by hurricanes, and in damage to infrastructure, and this trend looks
set to continue. The main reason for this, however, is that more and more
people are living and building in hurricane zones.

Most of these three paragraphs is entirely correct "“ there is no evidence
that hurricane numbers or intensity are effected by global warming, and if they
are, whether they are increased or decreased.  However, Hurricane Katrina
was most certainly NOT caused by global warming.  Why can't they just say
that?   It may have been made stronger or weaker.  Its course
may have been altered.   But it was not created by warming.  By
the way, the year after Katrina saw a much smaller than average Atlantic
hurricane season.

"¢ Higher
CO₂ levels will boost plant growth and food production

But it is extremely difficult to generalise
about the overall impact on plant growth. Numerous groups around the world have
been conducting experiments in which plots of land
are supplied with enhanced CO₂, while comparable nearby plots remain
at normal levels.

While these experiments typically have found
initial elevations in the rate of plant growth, these have tended to level off
within a few years. In most cases this has been found to be the result of some
other limiting factor, such as the availability of nitrogen or water.

So the answer is yes, but there is a diminishing return at some point.
Isn't that the same as can be said for the CO2 greenhouse effect?

Predicting the world's overall changes in food
production in response to elevated CO₂ is virtually impossible.
Global production is expected to rise until the increase in local average
temperatures exceeds 3°C, but then start to fall. In tropical and dry regions
increases of just 1 to 2°C are expected to lead to falls in production. In
marginal lands where water is the greatest constraint, which includes much of
the developing world but also regions such as the western US, the losses may
greatly exceed the gains.

Have you noticed yet that things that might hurt the AGW-interventionist's
case always seem "impossible to predict" while the climate is well within our
prediction capabilities?

As for food crops, the factors are more complex.
The crops most widely used in the world for food in many cases depend on
particular combinations of soil type, climate, moisture, weather patterns and
the infrastructure of equipment, experience and distribution systems. If the
climate warms so much that crops no longer thrive in their traditional settings,
farming of some crops may be able to shift to adjacent areas, but others may
not. Rich farmers and countries will be able to adapt more easily than poorer
ones.

I love the rich-poor language.  The leftish New Scientist simply can't
help itself.  But I will accept this statement, and go further:  This
is the reason that aggressive actions to reduce CO2 that reduce economic
growth, particularly in the developing world, may not make sense.  To the
extent that some climate change will occur no matter what, or is already
programmed by our past actions, then a richer world can deal with it better
than a poorer one.

"¢ Polar
bear numbers are increasing

Yet recently there have been
claims that polar bear populations are increasing. So what's going on? There
are thought to be between 20,000 and 25,000 polar bears in 19 population groups
around the Arctic. While polar bear numbers are increasing in two of these
populations, two others are definitely in decline. We don't really know how the
rest of the populations are faring, so the truth is that no one can say for
sure how overall numbers are changing.

Again, I love this.  We can know the global temperature
increase over a century to a tenth of a degree but it is impossible to count
polar bears.

A comprehensive review (pdf) by the US Fish and Wildlife Service
concluded that shrinking sea ice is the primary cause for the decline seen in
these populations, and it recently proposed listing
polar bears as threatened (pdf) under the Endangered Species Act. The
International Conservation Union projects the bears' numbers will drop by 30% by 2050
(pdf) due to continued loss of Arctic sea ice.

Note that down 30% (which coming from an environmental
advocacy ground has got to be considered the most extreme possible estimate) is
not "extinct."  The article fails to address at all the issue that polar
bears have survived through eras when Arctic sea ice melted completely in the
summers.  And there are many reasons for threats to polar bear numbers "“
most experts would say that hunting and threats to habitat are much more
important factors than global temperatures.

The table of contents for the rest of this paper, . 4A Layman's Guide to Anthropogenic Global Warming (AGW) is here.  Free pdf of this Climate Skepticism paper is here and print version is sold at cost here

The open comment thread for this paper can be found here. 

The table of contents for the rest of this paper, . 4A Layman's Guide to Anthropogenic Global Warming (AGW) is here.  Free pdf of this Climate Skepticism paper is here and print version is sold at cost here

As stated in the introduction, the purpose of this paper has
not been to provide a balanced portrayal of Anthropogenic Global Warming (AGW) theory; its purpose instead is to
provide a comprehensive overview of skeptic's concerns with AGW theory.
However, the issues raised here are not necessarily new, and AGW supporters
have attempted to address many of them. 

The New
Scientist, a fairly strong and reliable voice for advocacy of anthropogenic
global warming theory, recently published its response to what it calls 26
myths about global warming, many of these "myths" being correlated loosely with
skeptics concerns about AGW theory as outlined in this paper.  Walking
through their points seems a reasonable way to entertain a rebuttal to the
skeptic's position.  Each of these has a link to the New Scientist article
in question.  I have tried to summarize the position with a quote, shown
in italics.  My response to each then follows.

Before I get into these 20 myths, note that many of the key
skeptic's questions are neatly avoided.   While the magazine gives
itself certain softball questions, it does not attempt to take on skeptics
questions such as:

• Isn't warming from CO2 a diminishing return, such that each 10ppm of CO2
  has less warming effect than the last 10 ppm?
• Isn't warming from CO2 asymptotic, such that total warming from CO2 is
  capped?
• Isn't 2/3 or more of the future warming in IPCC forecasts due to
  positive feedback effects that tend to be rare in stable systems and that even
  the IPCC admits are poorly understood?
• Aren't there a lot of problems with ground-based temperature measurements?
• Aren't the historical proxies for temperature diverging from
  measurements, such that the IPCC actually dropped many of the recent proxy
  measurements to hide this result?

There are many others, but we can get at them tangentially
through dealing with the 20 "myths" below

"¢ Human
CO₂ emissions are too tiny to matter

So what's going on? It is true that human
emissions of CO₂ are small compared with natural sources. But the
fact that CO₂ levels have remained steady until very recently shows
that natural emissions are usually balanced by natural absorptions. Now
slightly more CO₂ must be entering the atmosphere than is being
soaked up by carbon "sinks".

Though I do know that some skeptics will claim that man can't be changing
world CO2 levels, I don't believe I even tried to make that claim in this paper.

The more salient point in
asking whether human CO2 emissions are too tiny to matter is to ask whether the
change in composition of the atmosphere of 0.009% by human activities is
substantial enough to affect world climate in any important way, particularly
when the portion being increased, CO2, is a relatively weak greenhouse gas vs.
other portions.

"¢ We
can't do anything about climate change

It is true that the action taken
so far, such as the Kyoto Protocol, will only have a marginal effect. The
protocol's authors have always described it as a first step. But even before it
came into effect in 2005, the protocol has triggered some profound thinking
among governments, corporations and citizens about their carbon footprint and
how to reduce it. Industrialized countries such as the UK are planning for
emissions reductions of 60% or more by mid-century.

This is a bit of a straw man.  Certainly to the extent
that man is causing climate change, men with enough will can do something about
it.  The question is whether the costs justify the avoided change "“ this
is a question that I have addressed sufficiently and won't revisit here.
However, I would like to comment on this:

We may find that once the
process has begun, the world loses its addiction to carbon fuels surprisingly quickly.
Natural scientists fear "tipping points" in the climate system. But there are
also tipping points in social, economic and political systems. Once under way,
things can happen fast"¦

This is a statement to which I both agree and disagree.  I am a technological
optimist, and so generally accept that world-changing technologies will
continue to spring from man's mind, and that the introduction of these changes
can be fast and their impact dramatic.  The only reason that I am a tad
skeptical about this statement is that the vast majority of strong AGW
adherents are technology pessimists, so it would be uncharacteristic for them
to take such a position.  Absent unimagined new technologies, change of
the type AGW supporters are hoping for is actually not a positive
feedback process as implied in this statement. Why is it that climate
scientists see so many positive feedback processes, when these are actually so
rare? In fact, most investment decisions, for example investments to reduce CO2
emissions, follow a diminishing return relationship.  Early investors
capture the low-hanging fruit, while each successive wave of investment offers
a lower return (here, in CO2 reduction) for each incremental dollar invested.

"¢ The
'hockey stick' graph has been proven wrong

Most researchers would agree that while the
original hockey stick can "“ and has "“ been improved in a number of ways, it was
not far off the mark. Most later temperature reconstructions fall within the
error bars of the original hockey stick. Some show far more variability leading
up to the 20^th century than the hockey stick, but none suggest that
it has been warmer at any time in the past 1000 years than in the last part of
the 20^th century.

No one statement by AGW supporters would do more to build my confidence in
their findings than to actually have someone say "the Mann hockey stick was a
deeply flawed analysis, and we have taken great pains to make sure the flaws identified
in Mann are not present in other historical reconstructions."  However,
when I see the statement above, I am left to wonder if any of the flaws in Mann
have actually been corrected in other works, or if systematic errors still
exist.  Since AGW supporters refuse to acknowledge flaws in Mann, it is
almost certain that these flaws still exist in the other analyses (therefore
making it unsurprising that new analyses show roughly the same results).
Remember that Mann was replaced by Biffra as lead author of this section of the
Fourth IPCC report, and it was Biffra who dropped 20-30 years of recent data
from his historical reconstruction when it did not show the result that he
wanted it to.

"¢ Chaotic
systems are not predictable

Getting reasonably accurate
predictions is a matter of choosing the right timescale: days in the case of
weather, decades in the case of climate.

Climate scientists sometimes
refer to the effects of chaos as intrinsic or unforced variability: the
unpredictable changes that arise from the dynamic interactions between the
oceans and atmosphere rather than being a result of "forcings" such
as changes in solar irradiance or greenhouse gases.

The crucial point is that
unforced variability occurs within a relatively narrow range. It is constrained
by the major factors influencing climate: it might make some winters bit a
warmer, for instance, but it cannot make winters warmer than summers

There are systems people who would both agree and disagree
with this statement.  The real study of chaotic systems is barely older
than the study of global warming, and most mathematicians would say that the
issue of long-term predictability of macro trends in chaotic systems is not
settled science.

However, one issue the statement overlooks is that even if
chaotic systems have some long-term order, at least when "viewed from a
distance," this does not mean that the drivers of those long-term trends can be
discerned by those of us standing in the chaos.  So while it may be
theoretically possible to predict long-scale climate changes, it may still be
impossible to discern the true drivers of these climate systems amidst the
chaos, making the long-term prediction problem moot.

Remember, no one has a thermometer that provides two readings "“ temperature
due to "natural" causes and temperature due to man-made forcings. 
The only argument one can make outside of a laboratory is to try to correlate
temperature changes to certain other variables, like CO2 level.  But in a
chaotic system, when thousands of variables may matter, and there are all kinds
of cross-dependencies between variables, definitively showing direct
correlation, much less causation, is very hard, possibly impossible. 
Remember, outside lab experiments, climate scientists main argument that CO2 is
causing current warming is "We have checked everything else it possibly could
be, and it wasn't those things, so it must be CO2."  In a chaotic system,
such a statement borders on hubris.

"¢ We
can't trust computer models of climate

Climate is average weather, and it can vary unpredictably
only within the limits set by major influences like the Sun and levels of
greenhouse gases in the atmosphere. We might not be able to say whether it will
rain at noon in a week's time, but we can be confident that the summers will be
hotter than winters for as long as the Earth's axis remains tilted.

The validity of models can be tested against
climate history. If they can predict the past (which the best models are pretty
good at) they are probably on the right track for predicting the future "“ and
indeed have successfully done so.

I hope that if you have learned anything from this paper, you already know
how to refute the statement above.  Climate models match history because
they have been tuned and tweaked and overridden to do so.  The fact that
they then can reproduce history is meaningless.  Even more, you should run
away quickly from anyone who makes this statement, because they are either
ignorant of what they are talking about or they are trying to sell you the
Brooklyn Bridge.

Finally, the claim is sometimes
made that if computer models were any good, people would be using them to
predict the stock market. Well, they are!

A lot of trading in the
financial markets is already carried out by computers. Many base their
decisions on fairly simple algorithms designed to exploit tiny profit margins,
but others rely on more sophisticated long-term models.

Sorry, but this is a facile and ignorant mis-interpretation of what
financial models are doing.  Yes, people are running long-term financial
models as part of a trading strategy, but these models feed into very
short-term trading decisions.  If you looked at the output from these long-term
models, you would see that they are changing constantly as new data flows
in.  There is an old joke about two campers who see a bear growling at
them.  One of them starts putting his tennis shoes on.  The other one
says to him "Why are you putting your shoes on?  You can't outrun that
bear."   His friend replied "I don't have to outrun the bear.  I
just have to outrun you."  Traders' long-term models work the same.
They don't actually expect them to be right, they just want them to be better,
based on current conditions, than other traders' models, then they can make
money.

"¢ They
predicted global cooling in the 1970s

Indeed they did"¦. However, Schneider soon
realised he had overestimated the cooling effect of aerosol pollution and
underestimated the effect of CO₂, meaning warming was more likely
than cooling in the long run"¦.

The calls for action to prevent further
human-induced global warming, by contrast, are based on an enormous body of
research by thousands of scientists over more than a century that has been
subjected to intense "“ and sometimes ferocious "“ scrutiny. According to the
latest IPCC report, it is more than
90% certain that the world is already warming as a result of human activity

We have already dealt with aerosols, and unlike many skeptics I have not
really held the 1970's global cooling panic against the climate
community.  The last paragraph is just circular.  Saying the IPCC is
90% sure does not answer the arguments about what skeptics feel the IPCC is
ignoring.

"¢ It's
been far warmer in the past, what's the big deal?

First of all, it is worth bearing in mind that
any data on global temperatures before about 150 years ago is an estimate, a
reconstruction based on second-hand evidence such as ice cores and isotopic
ratios. The evidence becomes sparser the further back we look, and its
interpretation often involves a set of assumptions. In other words, a fair
amount of guesswork.

This is hilarious.  What happened to their confidence in Mann and
1000-year temperature reconstructions just a few myths back?  But to
continue, the answer is basically yes, but:

The important question is what
is causing the current, rapid warming? We cannot dismiss it as natural
variation just because the planet has been warmer at various times in the past.
Many studies suggest it can only be explained by taking into account human
activity.

Nor does the fact that it has
been warmer in the past mean that future warming is nothing to worry about. The
sea level has been tens of metres higher during past warm periods, enough to
submerge most major cities around the world.

Here is why it matters "“ beyond the laboratory evidence of the greenhouse
effect, which tells us merely that there is an affect and not how strong it is,
the main evidence cited by AGW supporters for current warming being man-made is
to try to show that current warming is somehow unprecedented, and therefore
unlikely to be natural.  So it is odd here that AGW supporters simply
shrug their shoulders here and say that it is not important that current
warming be unprecedented.

"¢ It's
too cold where I live - warming will be great

This does not sound too bad, and for many people
it won't be. Wealthy individuals and countries will be able to adapt to most
short-term changes, whether it means buying an air conditioner or switching to
crops better suited to the changing climate. Rainfall will fall in
mid-latitudes but rise in high latitudes, and initially agricultural yields
will probably.  Some regions will suffer, though. Africa could be hardest
hit, with yields predicted to halve in some countries as early as 2020.

As global temperature climbs to 3°C above
present levels - which is likely
to happen before the end of this century if greenhouse emissions continue
unabated - the consequences will become increasingly severe. More than a third
of species face extinction. Agricultural yields will start to fall in many
parts of the world. Millions of people will be at risk from coastal flooding.
Heatwaves, droughts, floods and wildfires will take an ever greater toll.

I hope readers will accept that I am not exaggerating or constructing straw
men when I talk about the dire predictions by AGW supporters.  There is
nothing here that we have not dealt with earlier, except perhaps the
rainfall.  Of late, AGW supporters seem to have shifted to rainfall
(rather than sea level rise) as their lead scary topic.  Note, however,
that even the IPCC admits that it and all of its modelers really do not
understand (even a little bit) the effect of global warming on rainfall and
drought.  Logic says that with more water evaporated, while global warming
may cause now local draughts, overall rainfall should increase.  I would
bet any amount of money that lower economic growth due to aggressive CO2 abatement
will have a far more deleterious effect on worldwide agricultural yields than
global warming.

"¢ Global
warming is down to the Sun, not humans

So what role, if any, have solar fluctuations
had in recent temperature changes? While we can work out how Earth's orbit has
changed going back many millions of years, we have no first-hand record of the
changes in solar output associated with sunspots before the 20^th century.

It is true that sunspot records go back to the
17^th century, but sunspots actually block the Sun's radiation. It is
the smaller bright spots (faculae) that increase the Sun's output and these
were not recorded until more recently. The correlation between sunspots and
bright faculae is not perfect, so estimates of solar activity based on sunspot
records may be out by as much as 30%.

The other method of working out past solar
activity is to measure levels of carbon-14 and beryllium-10 in tree rings and
ice cores. These isotopes are formed when cosmic rays hit the atmosphere, and
higher sunspot activity is associated with increases in the solar wind that
deflect more galactic cosmic rays away from Earth. Yet again, though, the
correlation is not perfect. What is more, recent evidence suggests that the
deposition of beryllium-10 can
be affected by climate changes, making it even less reliable as a measure
of past solar activity.

This is again a pretty hilarious statement.  One could easily argue
that temperature and CO2 proxies have at least as much
uncertainty.  One wonders why AGW advocates do not seem as concerned about
the errors in the proxies they hold dear.  But anyway, to continue:

But even if solar forcing in the past was more
important than this estimate suggests, as some scientists think, there is no
correlation between solar activity and the strong warming during the past 40
years. Claims that this is the case have not stood up to scrutiny (pdf document).

Direct measurements of solar output since 1978
show a steady rise and fall over the 11-year sunspot cycle, but no upwards or downward trend .

Similarly, there is no trend in direct
measurements of the Sun's ultraviolet output and in cosmic rays. So for the
period for which we have direct, reliable records, the Earth has warmed
dramatically even though there has been no corresponding rise in any kind of
solar activity.

This is another you-study-my-study pissing match.  I am happy to admit
that our knowledge of the sun's changing impact on climate is poor, and that it
is hard to separate out this one effect in a chaotic system.  I refuse to
fall into the same scientific hubris as AGW supporters.  However, those
who think the sun has some contribution to warming are buttressed by the
knowledge that they are working with the main driver of climate, rather than a
secondary variable.

"¢ It's
all down to cosmic rays

There is no convincing evidence
that cosmic rays are a major factor determining cloud cover. The ionising of
air by cosmic rays will impart an electric charge to aerosols, which in theory
could encourage them to clump together to form particles large enough for cloud
droplets to form around, called "cloud condensation nuclei".

But cloud physicists say it has
yet to be shown that such clumping occurs. And even if it does, it seems
far-fetched to expect any great effect on the amount of clouds in the atmosphere.
Most of the atmosphere, even relatively clean marine air, has plenty of cloud
condensation nuclei already.

A series of attempts by
Svensmark to show an effect have come unstuck. Initially, Svensmark claimed
there was a correlation between cosmic ray intensity and satellite measurements
of total cloud cover since the 1980s "“ yet a correlation does not prove cause
and effect. It could equally well reflect changes in solar irradiance, which
inversely correlate with cosmic ray intensity.

I am starting to notice a trend here of making statements about competing
that could be applied equally well to AGW theory.  And what about all
those points they made above, reminding us over and over that CO2 greenhouse
theory works in the lab.  Now the lab is not good enough?

However, I would accept that the cosmic ray theory is pretty undeveloped and
not acceptably proven.  It has had a number of fits and starts.  Just
like CO2 greenhouse theory, the cosmic ray effect on climate can be reproduced
in the lab, but it is really hard to parse out its effects in the chaotic
climate.

"¢ CO₂
isn't the most important greenhouse gas

At some of these overlaps, the
atmosphere already absorbs 100% of radiation, meaning that adding more
greenhouse gases cannot increase absorption at these specific frequencies. For
other frequencies, only a small proportion is currently absorbed, so higher
levels of greenhouse gases do make a difference.

This means that when it comes to
the greenhouse effect, two plus two does not equal four.

Wow!  An AGW supporter actually said this in public.  This is to
our point that there is a diminishing return from incremental CO2 in the
atmosphere.  Of course, they say this in the context of trying to show why
water isn't as important as it might seem, but still, it's there

But the overall quantities of these other gases
are tiny. Even allowing for the relative strength of the effects, CO₂
is still responsible for two-thirds
of the additional warming caused by all the greenhouse gases emitted as a
result of human activity.

Water vapour will play a huge role in the
centuries to come, though. Climate models, backed by satellite
measurements, suggest that the amount of water vapour in the upper
troposphere (about 5 to 10 kilometres up) will double by the end of this
century as temperatures rise.

This will result in roughly twice as much
warming than if water vapour remained constant. Changes in clouds could lead to
even greater amplification of the warming or reduce it "“ there is great uncertainty
about this. What is certain is that, in the jargon of climate science, water
vapour is a feedback, but not a forcing.

Again, I am not getting into this, we covered it plenty in the paper.
When they say "CO2 is still responsible for two-thirds of the additional
warming" (and remember this is an output of their models, not any other
analysis)  what they really mean is that "our models that were programmed
to have CO2 drive the climate show that CO2 drives the climate."
Note that in a three paragraph answer about the effect of water vapor as
a climate feedback, only three words "“ "or reduce it" "“ acknowledge that it
might actually have a negative feedback effect, despite the fact that even the
IPCC includes cloud cover as a negative feedback.  They just don't want to
admit a negative feedback might even exist.

"¢ The
lower atmosphere is cooling, not warming

One study in Science
revealed errors in the way satellite data had been collected and interpreted.
For instance, the orbit of satellites gradually slows, which has to be taken
into account because it affects the time of day at which temperature recording
are taken. This problem was always recognised, but the corrections were given
the wrong sign (negative instead positive and vice versa).

A second study, also
in Science, looked at the weather balloon data. Measurements of the air
temperature during the day can be skewed if the instruments are heated by
sunlight. Over the years the makers of weather balloons had come up with better
methods of preventing or correcting for this effect, but because no one had
taken these improvements into account, the more accurate measurements appeared
to show daytime temperatures getting cooler.

The corrected temperature records show that
tropospheric temperatures are indeed rising at roughly the same rate as surface
temperatures. Or, as a 2006 report by the US Climate Change Science Program (pdf) puts
it: "For recent decades, all current atmospheric data sets now show
global-average warming that is similar to the surface warming." This one
appears settled.

There is still some ambiguity in the tropics,
where most measurements show the surface warming faster than the upper
troposphere, whereas the models predict faster warming of the atmosphere.
However, this is a minor discrepancy compared with cooling of the entire
troposphere and could just be due to the errors of margin inherent in both the
observations and the models.

First, observe absolutely ruthless efforts to apply corrections and
adjustments to any measurement that does not fit their theory, while blithely
accepting the surface temperature measurements that we showed can be really
unreliable.  Given the choice of focusing on managing satellite
temperatures up or surface temperature down, you can see which they
chose.   Second, note that this is another narrow one study
conclusion.  AGW supporters frequently cite single studies (conducted by
AGW supporters) that overturn skeptics arguments as having "settled" the
issue.  There are still many reasons to think that troposphere temperature
increases are less than surface increases.  Finally, even temperature
increases that were the same between the surface and the troposphere would be a
real problem for AGW theory.  The authors here act like this
surface-troposphere issue is a minor deal, but in fact if AGW theory is right,
the troposphere has to warm more, because that is where the extra heat
is being absorbed.  This is not at all settled. 

"¢ Antarctica
is getting cooler, not warmer, disproving global warming

It is clear that the Antarctic Peninsula, which juts
out from the mainland of Antarctica towards South America, has warmed
significantly. The continent's interior was thought to have warmed too, but in
2002 a new analysis of
records from 1966 to 2000 concluded that it has cooled overall"¦.

Climate models do not predict an evenly spread
warming of the whole planet: changes in wind patterns and ocean currents can
change the distribution of heat, leading to some parts warming much faster than
average, while others cool at first.

Agreed

"¢ The
oceans are cooling

Now the authors of the 2006 study have submitted a
correction (pdf format). It turns out that a fault in the software on some
of the floats led to some temperature measurements being associated with the
wrong depth.

Meanwhile, work by other teams suggests that the
past warmth of the oceans has been overestimated. The problem was due to
expendable sensors that are thrown overboard and take measurements as they
sink.

I never had heard the claim that the oceans were cooling, so it does not
surprise me that they are not.  However, it is again interesting the
amount of due diligence that AGW supporter put in to the correction of any
temperature measurement the might refute global warming, while blithely
accepting the atrocious condition and biases in ground-based temperature
measurement because, well, because these instruments are telling the story they
want to hear.

"¢ The
cooling after 1940 shows CO₂ does not cause warming

The mid-century cooling appears to have been
largely due to a high concentration of sulphate aerosols in the atmosphere,
emitted by industrial activities and volcanic
eruptions. Sulphate aerosols have a cooling effect on the climate because
they scatter light from the Sun, reflecting its
energy back out into space.

The rise in sulphate aerosols was largely due to
the increase in industrial activities at the end of the second world war. In
addition, the large eruption of Mount Agung in 1963 produced aerosols which cooled the
lower atmosphere by about 0.5°C, while solar activity levelled off after
increasing at the beginning of the century

I think I was pretty fair in discussing the aerosol cooling hypothesis in
this paper, though many would disagree with the above statement's certainty.

Climate models that take into account only
natural factors, such as solar activity and volcanic eruptions, do not
reproduce 20th century temperatures very well. If, however, the models include
human emissions, including greenhouse gases and aerosols, they accurately reproduce
the 1940 to 1970 dip in temperatures.

I hope readers who have made it this far can supply the refutation of this
point:  Wrong, wrong, wrong.  Climate models initially matched
history poorly.  Today they match well because they have been tweaked and
adjusted and forced to match.  They match because they are programmed to
match.  And, as we discussed, they match only because they make
ridiculously low assumptions for natural forcings, and assume all natural
forcings causing temperatures to rise in the first half of the century
magically reversed in 1950, though there is no good evidence for it. 

"¢ It
was warmer during the Medieval period, with vineyards in England

In the southern hemisphere, the picture is even
more mixed, with evidence of both warm and cool periods around this time. The
Medieval Warm Period may have been partly a regional phenomenon, with the
extremes reflecting a redistribution of heat around the planet rather than a
big overall rise in the average global temperature.

What is clear, both from the temperature
reconstructions and from independent evidence "“ such as the extent of the
recent melting of mountain glaciers "“ is that the planet has been warmer in the
past few decades than at any time during the medieval period. In fact, the
world may not have been so warm for 6000 or even 125,000 years (see Climate myths: It has been warmer in the past,
what's the big deal?).

What really matters, though, is not how warm it
is now, but how warm it is going to get in the future. Even the temperature
reconstructions that show the greatest variations in the past 1000 years suggest
up until the 1980s, average temperature changes remained within a narrow band
spanning 1ºC at most. Now we are climbing out of that band, and the latest IPCC report (pdf format) predicts a further rise of
0.5ºC by 2030 and a whopping 6.4ºC by 2100 in the worst case scenario.

We have covered this pretty well in this paper, so again I won't go back
into it, except to highlight a couple of things we can learn from this
statement.  First, note the hubris again "“ it is warmer today than in the
last 125,000 years.  I sure wish there was a way to bet on this "“ I would
have only a one in 125,000 chance of being wrong in betting against this
statement.  Second, note the use of the worst case scenarios.  For
2100, we don't get the best case or even the average case, we get the worst
case.  Can you name another branch of science where people do this?
Can you imagine, say, a group out to measure the speed of light.  They are
going to get some middle figure with an error band of some range.
Wouldn't you expect them to day that they found the speed of light to be
so-and-so, plus or minus an error of such-and-such size?  If they were
climate scientists, they would instead announce that they have found the speed
of light could be as large as Z, that being the highest possible figure in
their error band.

"¢ We
are simply recovering from the Little Ice Age

Yet while there is some evidence of cold
intervals in parts of the southern hemisphere during this time, they do not appear to
coincide with those in the northern hemisphere. Such findings suggest the Little
Ice Age may have been more of a regional phenomenon than a global one.

Solar radiation was probably lower at times
during this period, especially during a dip in solar activity called the
Maunder minimum around 1700, but models and temperature reconstructions suggest
this would have reduced average global temperatures by 0.4ºC at most.

The larger falls in temperature in Europe and
North American may have been due to changes in atmospheric circulation over the
North Atlantic, or in the Gulf Stream, or both, reducing heat transport from
the tropics (see Climate
change sceptics lose vital argument).

The warming after the so-called Little Ice Age
may reflect both an increase in solar activity and a redistribution of heat
around the planet. In particular, the increase in global temperature in the
first half of the 20^th century may have been largely due to an increase
in solar activity. The continued warming in recent decades, however, cannot be
explained by increases in solar radiation alone

Remember the graphs we showed earlier "“ the arctic proxies look like the
current warming is a straight linear increase from the 1700s to today.  In
fact, in the IPCC spaghetti graph showing all those historic reconstructions,
they all show a natural warming from the 18^th and 19^th
century through the 20^th.  Again, AGW supporters really need to
explain why they are so confident that this natural warming trend stopped in
1945 or so, exactly and coincidently at the exact same moment that man-made
forcings caused the world to continue to warm, coincidently at about the same
rate it was warming naturally earlier in the century.

"¢ Warming
will cause an ice age in Europe

Few scientists think there will
be a rapid shutdown of circulation. Most ocean models predict no more than a
slowdown, probably towards the end of the century. This could slow or even
reverse some of the warming due to human emissions of greenhouse gases, which
might even be welcome in an overheated Europe, but the continent is not likely
to get colder than it is at present.

A slowdown in circulation would
affect many parts of the world by disrupting global rainfall patterns. But
these effects will be insignificant compared with the much greater changes
global warming will cause

I already mentioned that this had been refuted pretty well

"¢ Ice
cores show CO₂ increases lag behind temperature rises, disproving
the link to global warming

It takes about 5000 years for an
ice age to end and, after the initial 800 year lag, temperature and CO₂
concentrations in the atmosphere rise together for a further 4200 years.

What seems to have happened at
the end of the recent ice ages is that some factor "“ most probably orbital
changes "“ caused a rise in temperature. This led to an increase in CO₂,
resulting in further warming that caused more CO₂ to be released and
so on: a positive feedback that amplified a small change in temperature. At
some point, the shrinking of the ice sheets further amplified the warming.

Models suggest that rising
greenhouse gases, including CO₂, explains about 40% of the warming
as the ice ages ended. The figure is uncertain because it depends on how the
extent of ice coverage changed over time, and there is no way to pin this down
precisely.

I was extremely happy to see that they at least tried to
address the issue I raised, ie is it really realistic to have a process
dominated by positive feedback, and if so, why doesn't it run away.  Their
answer:

Finally, if higher temperatures lead
to more CO₂ and more CO₂ leads to higher temperatures,
why doesn't this positive feedback lead to a runaway greenhouse effect? There
are various limiting factors that kick in, the most important being that
infrared radiation emitted by Earth increases exponentially with temperature,
so as long as some infrared can escape from the atmosphere, at some point heat
loss catches up with heat retention.

Which might make sense EXCEPT that they are claiming that
today's temperature and level of CO2 are higher than these historical levels,
so we are already higher than the level where they claim "heat loss catches up
with heat retention."  So either their answer is right, and there is a
strong compensating process which is not built into their models, or they are
wrong and they still need to explain what keeps a positive feedback dominated
process from running away.

"¢ Ice
cores show CO₂ rising as temperatures fell

There are some mismatches though. Besides lags
at the end of ice ages, cores taken from the ice overlying the famous
lake below Vostok in Antarctica seemed to show that about 120,000 years
ago, the temperature plummeted sharply while CO₂ levels remained high
for many thousands of years.

The question is whether this is real or just a
reflection of the problems with working out the age of the trapped air and with
deuterium as a temperature indicator. Many researchers are working on ways to
independently date the air and the ice, and to improve temperature
reconstructions based on relative deuterium content. One involves working out
what is called the deuterium excess by comparing the relative amounts of
deuterium and oxygen-18 in the ice.

The deuterium excess reflects the temperature at
the sea surface where the water that later fell as snow evaporated, rather than
the surface temperature where the snow fell. It helps to reveal whether
variations in the relative deuterium content of the ice are a result of water
coming from a different source region rather than changes in local temperature.

In 2001, researchers used the deuterium excess to correct for some of the
problems with the temperature record of the Vostok ice core. Their results produce
a much closer fit between temperature and CO₂ levels and reduces the
mismatch around 120,000 years ago to a few thousand years.

I did not really raise this issue, as even the most enthusiastic AGW
supporter does not tend to claim that CO2 drives all historic temperature
changes.  However, again, note the pattern "“ any historic data that does
not fit with AGW data typically is scrutinized and "corrected." 
Articles discussing flaws in methodology in gathering such data are quickly published.
Contrast this with the difficulty scientists have in questioning any data that
supports AGW theory.  As we saw earlier, the New Scientist still can't
bring itself to utter the words "the Mann hockey stick was flawed."
Neither could the IPCC, they just sort of dropped it, or buried it in the midst
of 12 others, without even saying why the analysis that was the centerpiece of
their last report was strangely missing.

"¢ Mars
and Pluto are warming too

The Sun's energy output has not increased since
direct measurements began in 1978. If increased solar output really was
responsible, we should be seeing warming on all the planets and their moons,
not just Mars and Pluto.

Our solar system has eight planets, three dwarf
planets and quite a few moons with at least a rudimentary atmosphere, and thus
a climate of sorts. Their climates will be affected by local factors such as
orbital variations, changes in reflectance (albedo) and even volcanic
eruptions, so it would not be surprising if several planets and moons turn out
to be warming at any one time.

I agree we have a lot to learn about this, and nothing at all is
settled.  However, we now have evidence from at least 5 other terrestrial bodies
that are warming at the same time the Earth is warming.  Why do AGW
supporters resist at least investigating further?

"¢ Many
leading scientists question climate change

Climate change sceptics sometimes claim that
many leading scientists question climate change. Well, it all depends on what
you mean by "many" and "leading". For instance, in April
2006, 60 "leading scientists" signed a letter urging Canada's
new prime minister to review his country's commitment to the Kyoto protocol.

This appears to be the biggest recent list of
sceptics. Yet many, if not most, of the 60 signatories are not actively engaged
in studying climate change: some are not scientists at all and at least 15 are
retired.

Compare that with the dozens of statements on
climate change from various scientific organisations around the world
representing tens of thousands of scientists, the consensus position
represented by the IPCC reports and the 11,000 signatories to a petition condemning the Bush administration's
stance on climate science.

I have carefully avoided the game of dueling scientific numbers.  As to
the claim that the skeptic list "are not actively engaged in studying
climate change: some are not scientists at all and at least 15 are retired" I
would be thrilled if AGW supporters held to this standard in making their own
numbers.  But, they manage to abandon this standard by the next paragraph,
when they claim the pro-AGW numbers, like the 11,000, are open to the same
criticism (since there are only 500-600 true climate scientists in the world,
vs. physicist, meteorologists, etc). 

"¢ It's
all a conspiracy

Now that there is a consensus, those whose
findings challenge the orthodoxy are always going have a tougher time
convincing their peers, as in any field of science. For this reason, there will
inevitably be pressure on scientists who challenge the consensus. But findings
or ideas that clash with the idea of human-induced global warming have not been
suppressed or ignored "“ far from it.

Journalists do have an interest in promoting
themselves (and their books), while their employers want to boost their
audience and sell advertising. Publicity helps with all these aims, but you get
far more publicity by challenging the mainstream view than by promoting it.
Which helps explain why so many sections of the media continue to publish or
broadcast the claims of deniers, regardless of their merit.

The notion of a "conspiracy" of course, is a useful straw man, implying
devious villains in the SPECTRE conference room planning the overthrow of the
world.   I won't argue the point again, except to encourage you to
watch the news with a critical eye, and decide for yourself.  However, just
to get you started, ask yourself if these events are signs of healthy, unbiased
science:

· A
group of AGW supporters are trying to get the British government to use force
to block the publication of a skeptical movie (the Global Warming Swindle)

· AGW
supporters in California have included skeptical scientists such as MIT's Dr.
Richard Lindzen as defendants in a law suit, asking that damages be paid by
people and companies whose public speech doesn't conform to AGW theory

· Many
AGW skeptics have been unable to get scientists who have published publicly
funded research to reveal their data and methodology for critique.
Freedom of Information Act (FOIA) requests have become a necessary tool of
climate skeptics.

· When
a group began photographing temperature measurement points to document the
shortcomings in historical surface temperature measurements, the NOAA pulled
the locations of its measurement stations off the Internet so that these US
citizens could no longer take pictures of and critique US government
installations.

· Scientists
who question AGW theory are equated by AGW supporters with Holocaust deniers.

"¢ Hurricane
Katrina was caused by global warming

More data is needed settle the issue. Some are
looking to natural records of past
hurricane activity in stalagmites, lake deposits and coral rubble. Others
are re-analysing existing databases. In February 2007, one such re-analysis
concluded that over the past two decades, hurricane intensity has increased
in the Atlantic but not in other parts of the world (pdf format).

Yet another complicating factor is that changes
in climate can also change the paths that tropical cyclones tend to take,
determining whether they remain over oceans or strike land.

What every one agrees on is that over the past
few decades there has been a huge rise in the number of people being killed or
injured by hurricanes, and in damage to infrastructure, and this trend looks
set to continue. The main reason for this, however, is that more and more
people are living and building in hurricane zones.

Most of these three paragraphs is entirely correct "“ there is no evidence
that hurricane numbers or intensity are effected by global warming, and if they
are, whether they are increased or decreased.  However, Hurricane Katrina
was most certainly NOT caused by global warming.  Why can't they just say
that?   It may have been made stronger or weaker.  Its course
may have been altered.   But it was not created by warming.  By
the way, the year after Katrina saw a much smaller than average Atlantic
hurricane season.

"¢ Higher
CO₂ levels will boost plant growth and food production

But it is extremely difficult to generalise
about the overall impact on plant growth. Numerous groups around the world have
been conducting experiments in which plots of land
are supplied with enhanced CO₂, while comparable nearby plots remain
at normal levels.

While these experiments typically have found
initial elevations in the rate of plant growth, these have tended to level off
within a few years. In most cases this has been found to be the result of some
other limiting factor, such as the availability of nitrogen or water.

So the answer is yes, but there is a diminishing return at some point.
Isn't that the same as can be said for the CO2 greenhouse effect?

Predicting the world's overall changes in food
production in response to elevated CO₂ is virtually impossible.
Global production is expected to rise until the increase in local average
temperatures exceeds 3°C, but then start to fall. In tropical and dry regions
increases of just 1 to 2°C are expected to lead to falls in production. In
marginal lands where water is the greatest constraint, which includes much of
the developing world but also regions such as the western US, the losses may
greatly exceed the gains.

Have you noticed yet that things that might hurt the AGW-interventionist's
case always seem "impossible to predict" while the climate is well within our
prediction capabilities?

As for food crops, the factors are more complex.
The crops most widely used in the world for food in many cases depend on
particular combinations of soil type, climate, moisture, weather patterns and
the infrastructure of equipment, experience and distribution systems. If the
climate warms so much that crops no longer thrive in their traditional settings,
farming of some crops may be able to shift to adjacent areas, but others may
not. Rich farmers and countries will be able to adapt more easily than poorer
ones.

I love the rich-poor language.  The leftish New Scientist simply can't
help itself.  But I will accept this statement, and go further:  This
is the reason that aggressive actions to reduce CO2 that reduce economic
growth, particularly in the developing world, may not make sense.  To the
extent that some climate change will occur no matter what, or is already
programmed by our past actions, then a richer world can deal with it better
than a poorer one.

"¢ Polar
bear numbers are increasing

Yet recently there have been
claims that polar bear populations are increasing. So what's going on? There
are thought to be between 20,000 and 25,000 polar bears in 19 population groups
around the Arctic. While polar bear numbers are increasing in two of these
populations, two others are definitely in decline. We don't really know how the
rest of the populations are faring, so the truth is that no one can say for
sure how overall numbers are changing.

Again, I love this.  We can know the global temperature
increase over a century to a tenth of a degree but it is impossible to count
polar bears.

A comprehensive review (pdf) by the US Fish and Wildlife Service
concluded that shrinking sea ice is the primary cause for the decline seen in
these populations, and it recently proposed listing
polar bears as threatened (pdf) under the Endangered Species Act. The
International Conservation Union projects the bears' numbers will drop by 30% by 2050
(pdf) due to continued loss of Arctic sea ice.

Note that down 30% (which coming from an environmental
advocacy ground has got to be considered the most extreme possible estimate) is
not "extinct."  The article fails to address at all the issue that polar
bears have survived through eras when Arctic sea ice melted completely in the
summers.  And there are many reasons for threats to polar bear numbers "“
most experts would say that hunting and threats to habitat are much more
important factors than global temperatures.

The table of contents for the rest of this paper, . 4A Layman's Guide to Anthropogenic Global Warming (AGW) is here.  Free pdf of this Climate Skepticism paper is here and print version is sold at cost here

The open comment thread for this paper can be found here. 

A while back, I discussed an effort by Anthony Watts to create a pictorial data base of the US Historical Climate Network, the 1000 or so temperature and weather sensors whose data are used in historical climate numbers, including IPCC and NOAA and GISS global warming data bases. 

Already, this effort has identified numerous egregious installations that call into question the quality of historical temperature measurement.  Note here and here and here and here.  The whole data base is at SurfaceStations.org and my humble contributions are here and here.  Was 2006 the second warmest of all time, or did 2006 have the most hot exhaust blowing on measurement instruments?

Roger Pielke, a climate scientist in Colorado, reports on an odd response by the NOAA to this effort:

Recently, Anthony Watts has established a website [www.surfacestations.org] to record these photographs. He has worked to assure that the photographs are obtained appropriately.

As a result of this effort, NOAA has removed location information
from their website as to where they are located. This information has
been available there for years.

There are a few USHCN stations at people's homes, so in some cases there may be privacy concerns, but most all of the ones I have seen are at public locations, from fire houses to ranger stations to water plants.  Pielke offers up a logical solution for where there are privacy issues:

"over 4 years ago there was a big push in the Cooperative Observer
program to make sure that all 7000+ sites across the country were
photodocumented. All 120 Data Acquisition Programs were equipped with
high quality digital cameras. Most took photos. However, at the higher
levels where they were developing the upload and archive system for the
photos the issue of observer privacy was raised and as best we can tell
the result was that those photos were not archived and certainly are
not available."

This is a very disturbing development, as individuals in NOAA's
leadership have used their authority to prevent the scientific
community and the public access to critical information that is being
used as part of establishing climate and energy policy in the United
States.

The solution to this issue is, of course, straightforward. Either
make the photographs where datasets are being used in research (i.e.
the HCN sites), available, or permit others to take them. Privacy
rules, such as not publishing the names and addresses of the observers,
should be made, however, the photographs themselves, viewing the site,
and views in the four orthogonal directions must be public. Volunteers
who are HCN Cooperative Observers need to either grant this permission
or not volunteer.

If you observe the state of climate science at all, you will know that any measurement (e.g. satellite or radiosonde temperature measurements) that conflict even the slightest with the main story line of anthropogenic global warming are subjected to intense and withering scrutiny.  Even the tiniest source of error or methodological sloppiness in these conflicting data sets cause global warming zealots to throw out the data as flawed.  It is instructive that perhaps the sloppiest data set of all is the surface climate measurement system they use primarily to support their case, and it is one they show absolutely no interest in scrutinizing, or letting anyone else scrutinize.

Anthony Watts and Steven McIntyre make an interesting observation, using an example temperature measurement point in the US and Global Historical Climate Network (the network that most historic global warming estimates are made from).

Over time, temperature measurement points, even those nominally in the same town, tend to change.  The measurement technology changes (from bulbs to electronics) the location can move across town, and towns with their heat islands can encroach.  As a result, scientists try to make guesstimate corrections to the historical data to take these events into account. 

Taking just one example measurement point, at Petaluma CA, Watts and McIntyre show how two different adjustment approaches by scientists at this location change the historic warming measured by over 1.5 degrees C.  Note that this "noise" is more than twice the value of the estimated "signal" -- the estimated 0.6 degrees C global warming over the last century.

More on signal to noise ratios in global warming measurement.

I am just finishing up my paper "A Skeptical Layman's Guide to Anthropogenic Global Warming," and one thing I encounter a lot with sources and websites that are strong supporters of Anthropogenic Global Warming (AGW) theory is that they will often say such-and-such argument by skeptics was just disproved by so-and-so. 

For example, skeptics often argue that historical temperature records do not correct enough for the effects of urbanization on long-term measurement points.  The IPCC, in fact, has taken the position that what is called the urban heat island effect is trivial, and does not account for much or any of measured warming over the last 100 years.  To this end, one of the pro-AGW sites (either RealClimate.org or the New Scientist, I can't remember which) said that "Parker in 2006 has disproved the urban heat island effect."

Now, if you were going to set out to do such a thing, how would you do it?  The logical way, to me, would be to draw a line from the center of the city to the rural areas surrounding it, and take a bunch of identical thermometers and have people record temperatures every couple of miles along this line.  Then you could draw a graph of temperature vs. nearness to the city center, and see what you would find.

Is that what Parker did?  Uh, no.  I turn it over to Steve McIntyre, one of the two men who helped highlight all the problems with the Mann hockey stick several years ago.

If you are not a climate scientist (or a realclimate reader), you
would almost certainly believe, from your own experience, that cities
are warmer than the surrounding countryside - the "urban heat island".
From that, it's easy to conclude that as cities become bigger and as
towns become cities and villages become towns, that there is a
widespread impact on urban records from changes in landscape, which
have to be considered before you can back out what portion is due to
increased GHG.

One of the main IPCC creeds is that the urban heat island effect has
a negligible impact on large-scale averages such as CRU or GISS. The
obvious way of proving this would seem to be taking measurements on an
urban transect and showing that there is no urban heat island. Of
course, Jones and his associates can't do that because such transects
always show a substantial urban heat island. So they have to resort to
indirect methods to provide evidence of "things unseen", such as Jones
et al 1990, which we've discussed in the past.

The newest entry in the theological literature is Parker (2004, 2006),
who, once again, does not show the absence of an urban heat island by
direct measurements, but purports to show the absence of an effect on
large-scale averages by showing that the temperature trends on calm
days is comparable to that on windy days. My first reaction to this,
and I'm sure that others had the same reaction was: well, so what? Why
would anyone interpret that as evidence one way or the other on UHI?

He goes on to take the study apart in detail, but I think most of you can see that the methodology makes absolutely zero sense unless one is desperately trying to toe the party line and win points with AGW supporters by finding some fig leaf to cover up this urban heat island problem.  By the way, plenty of people have performed the analysis the logical way we discussed first, and have shown huge heat island effects:

(Click for a larger view)

The bottom axis by the way is a "sky-view" metric I had not seen before, but is a measurement of urban topology.  Effectively the more urbanized and the more tall buildings around you that create a canyon effect, the lower the sky view fraction.  Note that no one gets a number for the Urban Heat Island effect less than 1 degree C, and many hover around 6 degrees (delta temperature from urban location to surrounding rural countryside).  Just a bit higher than the 0.2C assumed by the IPCC.  Why would they assume such a low number in the face of strong evidence?  Because assuming a higher number would reduce historical warming numbers, silly.

Oh, and the IPCC argues that the measurement points it uses around the world are all rural locations so urban heat island corrections are irrelevant.  Below are some sample photos of USHCN sites, which are these supposedly rural sites that are used in the official historical warming numbers.  By the way, these US sites are probably better than what you would find anywhere else in the world. (All pictures from surfacesations.org)  As always, you can click for a larger view.

You can help with the effort of documenting all the US Historical Climate Network (USHCN) stations.  See my post here -- I have already done two and its fun!

Ross McKitrick has suggested a variation on a carbon tax that in effect challenges both Anthropogenic Global Warming (AGW) believers and skeptics to put their money where their mouth is.  I, for one, would accept this challenge.  He proposes a carbon tax on a sliding scale:

Suppose each country implements something called the T3 tax, whose U.S.
dollar rate is set equal to 20 times the three-year moving average of
the RSS and UAH estimates of the mean tropical tropospheric temperature
anomaly, assessed per tonne of carbon dioxide, updated annually. Based
on current data, the tax would be US$4.70 per ton, which is about the
median mainstream carbon-dioxide-damage estimate from a major survey
published in 2005 by economist Richard Tol.

He chooses the "tropical tropospheric temperature anomaly" because that is effectively the canary in the underground mine.  According to AGW theory, the troposphere (the lowest 10km of atmosphere) will be warmed more than the earth's surface.  McKitrick also says that AGW models show the tropics will be warmed more than high latitudes. 

This tax rate is low, and would yield very little emissions
abatement. Global-warming skeptics and opponents of
greenhouse-abatement policy will like that. But would global-warming
activists? They should -- because according to them, the tax will climb
rapidly in the years ahead.

The IPCC predicts a warming rate in
the tropical troposphere of about double that at the surface, implying
about 0.2C to 1.2C per decade in the tropical troposphere under
greenhouse-forcing scenarios. That implies the tax will climb by $4 to
$24 per tonne per decade, a much more aggressive schedule of emission
fee increases than most current proposals. At the upper end of warming
forecasts, the tax could reach $200 per tonne of CO2 by 2100, forcing
major carbon-emission reductions and a global shift to non-carbon
energy sources.

Global-warming activists would like this. But so
would skeptics, because they believe the models are exaggerating the
warming forecasts. After all, the averaged UAH/ RSS tropical
troposphere series went up only about 0.08C over the past decade, and
has been going down since 2002. Some solar scientists even expect
pronounced cooling to begin in a decade. If they are right, the T3 tax
will fall below zero within two decades, turning into a subsidy for
carbon emissions.

At this point the global-warming alarmists would leap up to slam the
proposal. But not so fast, Mr. Gore: The tax would only become a carbon
subsidy if all the climate models are wrong, if greenhouse gases are
not warming the atmosphere, and if the sun actually controls the
climate. Alarmists sneeringly denounce such claims as "denialism," so
they can hardly reject the policy on the belief that they are true.

Under
the T3 tax, the regulator gets to call everyone's bluff at once,
without gambling in advance on who is right. If the tax goes up, it
ought to have. If it doesn't go up, it shouldn't have. Either way we
get a sensible outcome.

I think many skeptics would jump at such a proposal (as long as there is some control on AGW supporters "restating" and "correcting" the satellite readings -- there is nothing AGW scientists are better at than "correcting" historical numbers that don't fit their story line).  One reason is that we skeptics know one of the AGW dirty little secrets:   In fact, against all predictions of the theory, the troposphere has been warming less than the surface.  Also, while I get conflicting inputs on whether the tropics or the northern latitudes should warm more, but if McKitrick is correct, the fact that the tropics have been warming less than higher norther latitudes (but more than southern latitudes) is also an inconsistency.  In case you don't keep a full set of tropospheric temperature histories sitting on your desk, here are several from Global Warming at a Glance.

Warming for the lower troposphere in the tropics, note the 0.2C anomaly (click any image for larger version):

Here is the lower troposphere for the Northern Hemisphere above the tropics which is warming more than the tropics, with a 0.3 degree anomaly

And here is a comparison of Global lower troposphere temperatures (in blue) vs. one compilation  by the GIS of measured surface temperatures in red.  Note the divergence, which is exactly opposite of what AGW theory says has to happen, given the surface temps have a 0.5 to 0.6 degree anomaly  Note that this may be because of some serious biases to ground based temperature measurement, but then that would mean that global warming is over-stated.

Look for my upcoming "Skeptical Layman's Primer to Anthropogenic Global Warming" or email me for a pre-release beta copy.