Coyote Blog

The Arizona Republic had a stealth hit piece on skeptics in the paper today and, unfortunately, I inadvertently helped.  My kids woke me up at 7:00 this morning (Yuk!) to tell me I was on the front page of the Arizona Republic.  I was quoted a couple of times in an article on climate change skeptics.   I have a couple of thoughts about an article that really has me depressed today.  If you want to know what I really think about climate, see my book and in my movie (both free online).

• After interviews, I am always surprised at what the writers chose to quote, and this article is no exception. 
• I spent most of the article trying to explain this simple data exercise, but I guess newspapers today are science-phobic and would rather write he-said-she-said articles than actually get into the numbers.  Unfortunately, the article leaves the impressions that we skeptics have problems with catastrophic global warming theory  "just because."
• The article is not about the skeptics' position, because it is not really stated.  In fact, more space is spent on refuting skeptics than is even given to skeptics themselves.  Here is the best test:  The skeptic's position would have been better served by not publishing this mess at all.
• Almost my entire discussion with the reporter was about the forecasts.  I said man is causing some warming, but there are simple tests to show it likely won't be catastrophic.  I even said that it was the catastrophists tactic not to argue this point, but to shift the debate to whether warming exists at all, where they have a much stronger argument. Despite this whole discussion with the reporter, the reporter allowed the catastrophists to shift the debate again.  They want to argue whether things are warmer, where they are on strong ground, and not about how much it will warming the future and whether this will justify massive government intervention, where they are on weak ground.

This article really frustrates me, and may pretty much spell the end for my ever giving an interview on the subject again (I will do a podcast on Monday, which I will link soon, but that is different because they can't edit me).  Despite it being an article about skeptics, the catastrophists are the only one that get any empirical evidence whatsoever into the article (however lame it may be).  This really ticked me off in particular:  I spent an hour giving specific empirical reasons why there were problems with forecasts and the theory.  The reporter then just printed a few quotes from me that made me look like an uninformed idiot, saying "just because."  Then they print this:

"There is clearly a group of thought that says because we're not seeing
debate now, it never happened in the scientific community," Huxman
said. "That is simply wrong. It did happen, and it's over. The debate
now is over the idiosyncrasies, the internal workings."

Incredibly, they also credulously reprint the absurd Newsweek ad hominem attacks on skeptics. 

What also got my attention was the companion article on an ASU professor who is a climate skeptic.  Incredibly, in the whole article, not one sentence is dedicated to explaining why the professor is a skeptic.  What is the empirical evidence he relies on, or the analysis he finds most compelling?  We never find out.  All we get is an article on dueling motivations.  For example, the Republic writes:

Despite his notoriety as a hero of the skeptic crowd, Balling's research and lifestyle contain some surprising contradictions.

He is in charge of climate studies at the Decision Center for a Desert
City, an ambitious ASU program that looks at how drought will affect
the Valley.

He's a registered independent and lives a lifestyle that the hardiest environmental activist would recognize as green....

If there was a competition for living green, "put the cards on the
table, and I'll beat 99 percent of the faculty here," Balling said.

He avoids driving and  doesn't own a cellphone.

He would even have liked to see Al Gore win the presidency in 2000.

So?  Why is this surprising?  Should we all naturally expect that skeptics all eat children for dinner?  And, of course, an article on a leading skeptic would not be complete without this:

Critics have assailed Balling's ties to industries.

Balling received more than $679,000 in research funding from
fossil-fuel-industry organizations between 1989 and 2002, according to
figures provided by ASU. He served as a scientific adviser to the
Greening Earth Society, a public-relations organization founded by the
Western Fuels Association to promote the benefits of global warming.

Uh, OK.  Here is a Coyote Blog challenge:  Find me one article in a mainstream newspaper or news weekly that even once checks the sources of funding for climate catastrophists.  This focus on funding and motivation and political affiliation for skeptics only is scandalously asymmetric.  But take a quick look at the article - 85% of it is related to motivation, either how good his green credentials are or how much money he gets from oil companies - and not any discussion of what he actually thinks. 

This final bit is especially funny.  Think of all the wacko professors out there that are warmly accepted by their universities and the academic community.  We're talking about folks all the way up to and including men who have gone to prison for torturing and murdering women.  But apparently having a climate skeptic on the faculty is just too much:

But his climate work has garnered the most national attention, which bothers some colleagues at ASU.

"For ASU, having Balling as such a prominent figure in the climate
debate has been awkward, not so much because of his positions but
because we have lacked scientists of similar stature whose work
supports more widely held, opposing views," Jonathan Fink, director of
ASU's Global Institute of Sustainability, wrote in an e-mail. "Hence we
have been viewed as somewhat of a fringe institution in the world of
climate-change research."

Wow, its terrible to see such ill-repute brought to America's #1 Party School.  And by the way, what the hell kind of strategy is this?  We want to make a name for ourselves in climate research, so to do so we think we should be just like all the other schools -- that's the way to differentiate ourselves!

I will post links to my podcast that is coming up Monday night.  After that, I am not sure.  I am pretty depressed about the state of the media on this issue.  I have a lot of interests and more than enough to do with my time that I may take a break from climate for a while.

Over at Climate Skeptic, I discuss the problem of graft.  No, not bribery (though I do have a beef with the industry cabal that supposedly funds all skeptics for not coming through with my check).  In this case, I discuss temperature reconstructions that graft one data series onto another, and try to draw conclusions about the inflection point which, suspiciously, occurs exactly at the spot the two series are spliced.

Over at Climate Skeptic, I post my single best argument why you shouldn't be panicked about anthropogenic global warming.

Over at Climate Skeptic, we can see Nicholas Stern, former chief economist of the World Bank, argue that the only way to really abate CO2 is for all the world's countries to be just like India.  I kid you not.  And, in fact I agree with him that if we really wanted to eliminate CO2 emissions with current technology, exactly this kind of poverty promotion program would be required.  I just don't think it's necessary that we adopt such a goal. 

As a postscript, I take on Mr. Stern's temperature forecasts of 2.5-3 degree C rise by 2050 and show why they make absolutely no sense in light of the last 100 years of empirical data.

Email I received with subject line "Climate Skeptic"

"How stupid are you"

Outstanding.  I love scientific discourse.

There has been a lot of interest in my new climate video.  Already we have nearly 450 1500 views at Google video and over 200 700 downloads of the video.  I am now releasing the video through YouTube.

YouTube requires that all videos be under 10 minutes, so I have broken the film into six parts.  If you want to just preview a portion, the second half of the fourth film and the first half of the fifth are probably the most critical.

A Youtube Playlist for the film is here.  This is a cool feature I have not used before, but will effectively let you run the parts end to end, making the 50-minute video more or less seamless. 

The individual parts are:

Climate Video Part 1:  Introduction; how greenhouse gases work; historical climate reconstructions
Climate Video Part 2:  Historical reconstructions; problems with proxies
Climate Video part 3:  How much warming is due to man; measurement biases; natural cycles in climate
Climate Video Part 4:  Role of the sun; aerosols and cooling; climate sensitivity; checking forecasts against history
Climate Video Part 5:  Positive and negative feedback;  hurricanes.
Climate Video Part 6:  Melting ice and rising oceans; costs of CO2 abatement; conclusions.

You may still stream the entire climate film from Google Video here. (the video will stutter between the 12 and 17 second marks, and then should run fine)

You may download a 258MB full resolution Windows Media version of the film by right-clicking here.

You may download a 144MB full resolution Quicktime version of the film by right-clicking here.

My first climate movie, What is Normal?  A Critique of Catastrophic Man-Made Global Warming Theory is now available for free download.  If you have the bandwidth, I encourage you to download the full 640x480 version as Windows Media Video, but be forewarned that the file is 258MB.  This is actually a pretty small file for a 50+ minute movie, and the full resolution version looks much nicer than the streaming version.

Right-Click Here to Download Climate Movie in Full Resolution

Right-Click here for full resolution 144MB .mov quicktime version of Climate Movie

Make sure you turn up your volume -- I think I recorded this with a pretty low audio level.

If you are bandwidth-challenged, or you can't view a .WMV file, you may stream the video from Google video or download a reduced resolution version here.  Unfortunately, to make the video stream effectively, the resolution is cut to 320x240, but having watched it, it still looks surprisingly good streamed. 

Note, on the streaming version, the video stutters between the 12 and 17 second marks in the movie, but runs fine after that.  By the way, thanks to all the commenters who gave me some good alternatives to using my own fairly week narration voice.  I decided for this first release I wanted to see what I could achieve with a pure solo effort.  Many thanks to Adobe Premier Elements, which made this effort possible.

Finally, you can stream the reduced resolution Google video version below:

Please check back Monday morning, as I will be releasing my new video, "What is Normal:  A Critique of Catastrophic Man-Made Global Warming Theory."  As with my global warming book, which began as a ten page summary and ended up as an 85-page manuscript, the video started at a goal of 15 minutes and eventually ended up at 50 minutes.  However, unlike other global warming-related videos I will not name, it is all climate science, with no self-congratulatory segments on my childhood.

"It's hot in the desert, so therefor warmer temperatures must cause drought."  That is the logical fallacy I address today over at Climate Skeptic, where we find evidence that, if anything, global warming is making things wetter rather than drier.

Anthony Watt has a pointer to a nice presentation in four parts on YouTube by Bob Carter made at a public forum in Australia.  He walks through some of the skeptics' issues with catastrophic man-made global warming theory.

What caught my attention, though, were the pictures Mr. Carter shows in his presentation about about 1:30 into part 4.  Because I took the pictures he shows, down at the University of Arizona, as part of Mr. Watts project to document temperature measurement stations.  Kind of cool to see someone I don't know in a country I have (sadly) never visited using a small bit of my work.  Part 4 is below, but you can find links to all four parts here.

Several readers have asked for my comment.  This is what I posted over at Climate Skeptic:

This
morning I was all fired up to write something petty, like "Al Gore now
has made the same contributions to peace as have previous winners
Yassir Arafat and Henry Kissinger."  Later, I considered a long and
drawn out post on the inaccuracies of "An Inconvinient Truth", but I
really have already done that in long form here and in short form here.
In truth, the Peace prize process has for years been about a group of
leftish statists making a statement, and often it has been about
tweaking the US, rather than a dispassionate analysis of true
contributions to peace made with the benefit of some historic distance
(as is done with the scientific prizes).  Further, most folks I argue
with don't really care about the specific inacuracies in Gore's movie,
their response typically being something in the "fake but accurate"
line of reasoning.

So instead I will say what I told a reader by email a few hours
ago.  I tend to be optimistic about the world, and believe that we are
approaching a high water mark (so to speak) for the climate
catastrophists, where we will look back and see their influence peak
and start unwinding under the presure of science and the reality of the
enormous cost to abate CO2.  Gore's Peace prize, in the same year as
his Oscar and that global warming music festival no one can even
remember the name of 3 months later, feels to me like it may be that
high water mark.   The Peace Prize certainly was the high water mark
for Jimmy Carter's credibility, not to mention that of Henry Kissinger
and a myriad of others.  Think of it this way -- if the guys who made
the peace prize decisions were investors, and you knew what they were
investing in, you would sell short.  Seriously, just look at the
group.  Well, they just invested in Al Gore.

Update:  One thing many commenters have not pointed
out is that Al Gore is really manuevering the US and China and India
(and the rest of the developping world) into a position that, if he has
his way, conflict is going to occur over who gets to grow and develop,
and who does not.  CO2 catastrophism has the ablility to be the single
most destabalizing issue of the 21st century. This is peace?

Up until now, the retreat of Arctic ice to 30 year lows has been credited, without proof, to global warming.  This never made a lot of sense to me, since at the same time Antarctic sea ice was hitting an all-time high.  Over at Climate Skeptic, I discuss a new NASA study that proposes that Arctic sea ice melting over the last decade has been due mainly to shifting wind patterns that basically push the ice into warmer waters where it melts faster.

Over at Climate Skeptic, some investigation by the folks at SPPI have shown that in her new children's climate propaganda book, Laurie David actually reversed the legend on a key chart showing the 600,000 year history of CO2 and temperature.  Recent analysis has shown, and most all scientists accept, that temperature increases actually preceded CO2 increases by 800 or more years in many of the past glacial cycles.  Since this did not fit her story, David reverses the chart legend, making CO2 precede temperature the way David wants it.  Going right to David's cited source, we find:

On page 103 of their book, David and Gordon cite the work of Siegenthaler et al.
(2005), for their written and graphical contention that temperature lags CO2.
However, Siegenthaler et al. clearly state the opposite:

"The
lags of CO2 with respect to the Antarctic temperature over
glacial terminations V to VII are 800, 1600, and 2800 years, respectively, which
are consistent with earlier observations during the last four glacial
cycles."

(Siegenthaler et al., 2005, Science, vol. 310,
1313-1317)

More, including the graphs themselves, before and after tampering, at climate skeptic.

Over at Climate Skeptic, some investigation by the folks at SPPI have shown that in her new children's climate propaganda book, Laurie David actually reversed the legend on a key chart showing the 600,000 year history of CO2 and temperature.  Recent analysis has shown, and most all scientists accept, that temperature increases actually preceded CO2 increases by 800 or more years in many of the past glacial cycles.  Since this did not fit her story, David reverses the chart legend, making CO2 precede temperature the way David wants it.  Going right to David's cited source, we find:

On page 103 of their book, David and Gordon cite the work of Siegenthaler et al.
(2005), for their written and graphical contention that temperature lags CO2.
However, Siegenthaler et al. clearly state the opposite:

"The
lags of CO2 with respect to the Antarctic temperature over
glacial terminations V to VII are 800, 1600, and 2800 years, respectively, which
are consistent with earlier observations during the last four glacial
cycles."

(Siegenthaler et al., 2005, Science, vol. 310,
1313-1317)

More, including the graphs themselves, before and after tampering, at climate skeptic.

From
Megan McArdle:

Matt may be right that I haven't harangued people about climate change
recently, so here goes: dude, if you're still a climate change skeptic, it's
time for a rethink. When the science correspondent for Reason magazine
comes over to the reality of anthropogenic global warming, it's safe to say that
the skeptics have lost the debate. Not only the vast majority of the scientific
community, but even most of the hard-core skeptics at conservative magazines,
have abandonned the hope that we are not warming up the climate.

There's still debate about the effects of the warming, and what we should do
about it. But there's not much question that it's happening.

Duh.  The vision of the skeptic community denying that the world is
warming at all is a straw man created by the climate catastrophists to avoid
arguing about the much more important point in her second paragraph.  What I
can't understand is McArdle's, and many intelligent people I meet, seeming
unintrest in the degree of man-made impact.

The chief debate really boils down to those of us who think that
climate sensitivity to CO2 is closer to 1C (ie the degrees the world will warm
with a doubling of CO2 concentrations from pre-industrial levels) and those who
think that the sensitivity is 3-5C or more.  The lower sensitivity implies a
warming over the next century of about a half degree C, or about what we saw in
the last century.  The higher numbers represesent an order of magnitude more
warming in the next century.  The lower numbers imply a sea level rise measured
in inches.  The higher numbers imply a rise of 1-2 feet  (No one really know
where Al Gore gets his 20 foot prediction in his movie).  The lower numbers we
might not even notice.  The higher numbers will certainly cause problems.

The other debate is whether the cost of CO2 abatement should even be
considered.  I have talked to many people who say the costs are irrelevant -
Gaia must come first.  But steps to make any kind of dent in CO2 production with
current technologies will have a staggering impact on the world economy.  For
example, there are a billion Asians poised to finally to enter the middle class
who we will likely consign back to poverty with an aggressive CO2 reduction
program.  With such staggering abatement costs, it matters how bad the
effects of man-made global warming will be. 

There are many reasons a 1.0 climate sensivity is far more defensible
than the higher sensitivities used by catastrophists.  My
argument a lower climate sensitivity and therefore a less aggresive posture on
CO2 is here.  Cross-posted at Climate Skeptic.

Update: Sure, we skeptics debate the degree of past warming, but it really can't be denied the earth is warmer than 100 years ago.  The problem catastrophists have with defending their higher climate sensitivities is that these sensitivities imply that we should have seen much more warming over the past 100 years, as much as 1.5C or more instead of about 0.6C.  These scientists have a tendency to try to restate historical numbers to back their future forecast accuracy.  We skeptics fight them on this, but it does not mean we are trying to deny warming at all, just make sure the science is good as to the magnitude.

One other thought - everyone should keep two words in mind vis a vis CO2 and its effect on temperature:  Diminishing Return.  Each new molecule of CO2 has less impact on temperature than the last one.  Only by positing a lot of weird, unlikely, and unstable positive feedbacks in the climate can scientists reach these higher sensitivity numbers (more here).  A good economist would laugh if they understood the assumptions that were being made in the catastrophic forecasts that are being used to influence government action.

Cars made by GM and fuel produce by Exxon may be responsible for a lot of CO2, but no one is creating as much global warming as James Hansen and NASA do just sitting at their computers.  An example, showing a cooling trend in New Zealand before their adjustments, but a strong warming trend after NASA is through with the data, is posted at Climate Skeptic.

Over at Climate Skeptic, I discuss Anthony Watt's preliminary findings as to the quality of measurement in the surface temperature installations that are used to measure global warming.  If we call global warming "the signal", then the signal is currently thought to have been about 0.6C over the last century.  However, Watt has good reason to estimate that 85% of the US Historical Climate Network has installation biases that create errors from 1-5C,or about 2-8 times the signal.  And these are not random biases that cancel out, but tend to all bias the numbers higher, leading to systematic over-estimation of temperature increases.

Over at Climate Skeptic, I discuss Anthony Watt's preliminary findings as to the quality of measurement in the surface temperature installations that are used to measure global warming.  If we call global warming "the signal", then the signal is currently thought to have been about 0.6C over the last century.  However, Watt has good reason to estimate that 85% of the US Historical Climate Network has installation biases that create errors from 1-5C,or about 2-8 times the signal.  And these are not random biases that cancel out, but tend to all bias the numbers higher, leading to systematic over-estimation of temperature increases.

I am sure everyone has heard that Arctic sea ice is, as the National Geographic described it, at an "all-time low."  Of course those would expect the words "all-time" to mean just that will be disappointed to learn that they really mean "since 1979 when we started measuring it by satellite."

At Climate Skeptic, I write that it has come to my attention that the earth has two poles, and it's odd no one talks about the other one.  Maybe they forgot?  Well it turns out that Antarctic sea ice is at an all time high (using the term in the same way that National Geographic does). 

As an end note, I also discuss Glacier Bay, Alaska.  It turns out the glaciers there are retreating, but about 99% of the retreat occurred between 1793 and 1907. 

After NASA was forced to restate its US temperature data downward, James Hansen argued that the US doesn't matter.  After it was observed that long-term temperature measurement is flawed in South America and Africa, James Hansen agreed and argued that South America and Africa don't matter.  Since oceans cover 75% of the globe and we have no long-term temperature record for these oceans or for Antarctica, I ask the question at Climate Skeptic:  What does matter?

Good news this week:  James Hansen and NASA have now deigned to release for scrutiny their taxpayer-funded temperature aggregation and adjustment code.  I go in more detail and explain why this matters over at Climate Skeptic.

By the way, if you are wondering why I have calmed down a bit on climate of late here at Coyote Blog, it is because I have decided that my climate work really was diluting what I want to do here at Coyote Blog, and it really deserved its own home and audience.  I have begun archiving old posts over at Climate Skeptic, and I will do most of my new posting on climate there.  Those interested in the climate issues are encouraged to bookmark the new site and/or subscribe to its feed.

For a little while, I will still mirror the headlines over here at Coyote Blog (after all, the paint is still so wet over at Climate Skeptic that I don't think Google has found me yet -- a few blogrolls wouldn't hurt, hint, hint.)

Also, in the next few weeks I plan release my own video on issues with catastrophic anthropogenic (man-made) global warming theory.  The core of this video will be based on this skeptics summary post and my 60-second climate overview as well as my free 80-page skeptics primer, of course.

I am often asked, "why, if the threat of global warming is really so overstated, does the issue have such legs with politicians, media, and activists?"

Answer:  Because it is the perfect political bludgeon.  One of the reasons I felt like high school debate really was broken (I don't know if it has been fixed since) was because every single debate eventually devolved into which side was more likely to cause a nuclear war.  It didn't matter if you were arguing about energy policy or the presidential primary system, no good debate case stopped short of blaming the other side for nuclear war.

Today, with nuclear weapons mostly forgotten (unfortunately not gone), global warming is the new nuclear war. It doesn't matter what you are arguing about:

There was Clare Short, a member of the British Parliament and Secretary
for International Development under Prime Minister Tony Blair until she
resigned in 2003 over the Iraq war. Claiming that Israel is actually
"much worse than the original apartheid state" and accusing it of
"killing (Palestinian) political leaders," Ms. Short charged the Jewish
state with the ultimate crime: Israel "undermines the international
community's reaction to global warming." According to Ms. Short, the
Middle East conflict distracts the world from the real problem:
man-made climate change. If extreme weather will lead to the "end of
the human race," as Ms. Short warned it could, add this to the list of
the crimes of Israel.

NASA's GISS was recently forced to restate its historical temperature database for the US when Steve McIntyre (climate gadfly) found discontinuities in the data that seemed to imply a processing error.  Which indeed turned out to be the case (store here).

The importance of this is NOT the actual change to the measurements, though it was substantial.  The importance, which the media reporting on this has entirely missed, is it highlights why NASA and other government-funded climate scientists have got to release their detailed methodologies and software for scrutiny.  The adjustments they are making to historical temperatures are often larger(!) than the measured historical warming (here, here, here) so the adjustment methodology is critical. 

This post from Steve McIntyre really shows how hard government-funded climate scientists like James Hansen are working to avoid scientific scrutiny.  Note the contortions and detective work McIntyre and his readers must go through to try to back into what NASA and Hansen are actually doing.  Read in this context, you should be offended by this article.  Here is an excerpt (don't worry if you can't follow the particular discussion, just get a sense of how hard NASA is making it to replicate their adjustment process):

If I average the data so adjusted, I get the NASA-combined version
up to rounding of 0.05 deg C. Why these particular values are chosen is
a mystery to say the least. Version 1 runs on average a little warmer
than version 0 where they diverge ( and they are identical after 1980).
So why version 0 is adjusted down more than version 1 is hard to figure
out.

Why is version 2 adjusted down prior to 1990 and not after? Again
it's hard to figure out. I'm wondering whether there isn't another
problem in splicing versions as with the USHCN data. One big version of
Hansen's data was put together for Hansen and Lebedeff 1987 and the
next publication was Hansen et al 1999 - maybe different versions got
involved. But that's just a guess. It could be almost anything....It would be interesting to check their source code and see how they get this adjustment, that's for sure.

A basic tenant of science is that you publish enough information such that others can replicate your work.  Hansen and NASA are not doing this, which is all the more insane given that we as taxpayers pay for their work.

Hansen cites the fact that Phil Jones gets somewhat similar results as
evidence of the validity of his calculations. In fairness to Hansen,
while they have not archived code, they have archived enough data
versions to at least get a foothold on what they are doing. In
contrast, Phil Jones at CRU maintains lockdown anti-terrorist security
on his data versions and has even refused FOI requests for his data.
None of these sorts of analyses are possible on CRU data, which may or
may not have problems of its own.

My photo survey of the Tucson USHCN climate station is still creating a lot of discussion.  Discussion, for example, is here, here, and here.

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.  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.

OK, I understand that perhaps my worst flaw in trying to make a point is in being too loquacious.  In a previous post, I showed why estimates of climate catastrophe were overblown by using the earth's experience over the last 100 years as an empirical guide.  Today, I shall try to make the same point with fewer words and just two charts instead.

Scientists have a concept called climate sensitivity which refers to the amount of global warming in degrees Celsius we might expect from a doubling of CO2 concentrations from a pre-industrial 280ppm to 560ppm  (we are currently at about 380ppm today and will reach 560ppm between 2065 and 2100, depending on how aggressive a forecast you want to adopt).

A simple way to estimate sensitivity is from experience over the past century.  At the same time CO2 has gone up by 100ppm, global temperatures have gone up by at most 0.6 Celsius (from the 4th IPCC report).  I actually believe this number is over-stated due to uncorrected urban effects and other surface temperature measurement issues, but let's assume 0.6ºC.  Only a part of that 0.6ºC is due to man - some is likely do to natural cyclical effects, but again to avoid argument, let's assume man's CO2 has heated the earth 0.6 Celsius.  From these data points, we can project forward:

As you can see, the projection is actually a diminishing curve.  For reasons I will not go into again (you can read much more in my original post) this relationship HAS to be a diminishing curve.  It's a fact accepted by everyone.  True climate consensus.  We can argue about the slope and exact shape, but I have chosen midpoint values from a reasonable range.  The answer is not that sensitive to different assumptions anyway.  Even a linear extrapolation, which is clearly wrong scientifically, would only yield a sensitivity projection a few tenths of a degree higher.

What we arrive at is a sensitivity of about 1.2 degrees Celsius for a CO2 doubling (where the blue line crosses 560ppm).  In other words, we can expect another 0.6ºC increase over the next century, about the same amount we experienced (and most of us failed to notice) over the last century.

But, you are saying, global warming catastrophists get so much higher numbers.  Yes they do, with warming as high as 9-10C in the next century.  In fact, most global warming catastrophists believe the climate sensitivity is at least 3ºC per doubling, and many use estimates as high as 5ºC or 6ºC.  Do these numbers make sense?  Well, let's draw the same curve for a sensitivity of 3ºC, the low end of the catastrophists' estimates, this time in red:

To get a sensitivity of 3.0ºC, one has to assume that global warming due solely to man's CO2 (nothing else) would have to be 1.5ºC to date (where the red line intersects the current concentration of 380ppm).  But no one, not the IPCC or anyone else, believes measured past warming has been anywhere near this high.  So to believe the catastrophic man-made global warming case, you have to accept a sensitivity three or more times higher than historical empirical data would support.  Rather than fighting against climate consensus, which is how we are so often portrayed, skeptics in fact have history and empirical data on our side.  For me, this second chart is the smoking gun of climate skepticism.  We have a lot of other issues -- measurement biases, problems with historical reconstructions, role of the sun, etc -- but this chart highlights the central problem -- that catastrophic warming forecasts make no sense based on the last 100+ years of actual data.

Global warming catastrophists in fact have to argue against historical data, and say it is flawed in two ways:  First, they argue there are positive feedbacks in climate that will take hold in the future and accelerate warming; and second, they argue there are other anthropogenic effects, specifically sulphate aerosols, that are masking man-made warming.  Rather than just repeat myself (and in the interest in proving I can actually be succinct) I will point you to my original post, the second half of which deals in depth with these two issues. 

As always, you can find my Layman's Guide to Skepticism about Man-made Global Warming here.  It is available for free in HTML or pdf download, or you can order the printed book that I sell at cost.  My other recent posts about climate are here.