Coyote Blog

Here are some of the provisions in the bailout that converted "no" votes to "yes." Unbelievable.

Andrew Leonard goes digging in the Senate's bailout package and finds a bunch of "sweeteners" added to lure in votes.  Among them:

* Sec. 105. Energy credit for geothermal heat pump systems. * Sec. 111. Expansion and modification of advanced coal project investment credit. * Sec. 113. Temporary increase in coal excise tax; funding of Black Lung Disability Trust Fund. * Sec. 115. Tax credit for carbon dioxide sequestration. * Sec. 205. Credit for new qualified plug-in electric drive motor vehicles. * Sec. 405. Increase and extension of Oil Spill Liability Trust Fund tax. * Sec. 309. Extension of economic development credit for American Samoa. * Sec. 317. Seven-year cost recovery period for motorsports racing track facility. * Sec. 501. $8,500 income threshold used to calculate refundable portion of child tax credit. * Sec. 503 Exemption from excise tax for certain wooden arrows designed for use by children.

There
are also tax credits for solar and wind power, and a very expensive
requirement that health insurance companies cover mental health the
same way they cover physical health.

If you have watched the Olympics at all, you have likely seen the Obama commercial promising:

"The hands that install roofs can also install solar panels. The hands
that build today's cars can also build the next generation of
fuel-efficient vehicles. Barack Obama [will] ... create 5 million jobs developing homegrown energy technologies."

A few reactions:

• Private individuals, not politicians, create jobs
• Job promises like this are never incremental, nor can they be.  If the hands that build current SUV's can build electric cars instead, then we haven't added any new hands, we've just changed what they are working on.
• It strikes me that this is the broken windows fallacy writ large.  In effect, Obama promises to make much of our perfectly-serviceable transportation and electrical generation installed base obsolete, requiring an enormous effort to replace it.  But the resources to fund this huge new investment have to come from somewhere.  Industries that flourish and grow under this government enforced shift in capital will be offset by those that are starved.  Every other part of the economy will slow due either to higher taxes or higher prices (or both) that subsidize this effort.  But since it is harder to find and count the latter than the former, it makes for a good, un-auditable political pledge
• I'll bet that 5 million number focus groups really well, but does it make any sense at all?  Here are some current employment numbers for the US as of January, 2008:

OK, so the total employment of all these industries that might be related to an alternate energy effort is about 2.28 million.  So, to add 5 million incremental jobs would require tripling the size of the utility industry, tripling the size of the utility construction and equipment industry, tripling the size of the auto industry, tripling the size of the aircraft industry, and tripling the size of the shipbuilding industry.  And even then we would be a bit short of Obama's number.

Via Jonathan Adler:

The [two new solar] plants will cover 12.5 square miles of central California with
solar panels, and in the middle of a sunny day will generate about 800
megawatts of power, roughly equal to the size of a large coal-burning
power plant or a small nuclear plant.

I don't know this exact location, but you can see from here, the best one can probably expect from central California is about 6 peak sun-hours per day (more explanation here).  This means that even in a very good solar location, the plant will produce over the course of a year 25% (6/24) of nameplate capacity.  This means that to actually replace a large coal-burning power plant, 50 square miles of solar panels would be required  (assuming that one has a 100% efficient way to store power for non-sunny times, a technology that does not currently exist).

For a while, I have been writing that traditional silicon/germanium based solar-electric panels are not yet economic as an electricity source.

I have hopes for other technologies eventually making direct solar conversion to electricity.  However, there seems to be some activity in solar concentrating plants, where solar energy is reflected onto tubes to boil water and drive traditional steam turbines to generate electricity.  Fortune has an article on one such plant opening recently:

The completed solar arrays will be trucked to California where Ausra
is building a 177-megawatt solar power station for utility PG&E (PCG)  on 640 acres of agricultural land in San Luis Obispo County. (To see a video of the robots in action, click here.)
The arrays focus sunlight on water-filled tubes to create steam to
drive a turbine. Ausra manufacturing exec David McKay points to where
standard-issue boiler pipe will be fed into a machine and treated with
a proprietary coating that transforms it into a solar receiver.

I would love for this to work, but the article goes on to say that this approach still requires federal tax subsidies to compete with other electricity sources.  I am not very familiar with the economics of such plants.  Does anyone have a link or source that delves into the economics.  I am increasingly frustrated of late with alternate energy articles that fail to give any of the relevent economic info.  For example, I read an article in the Arizona Republic (sorry, lost the link) about Arizona's first wind project, but I could not get a sense from the article if the power was being purchased at market rates or some special inflated rate.

San Francisco has a ballot initiative this November to seize all PG&E transmission lines and assets in the city such that all city power comes from a new government owned utility.  Further, the initiative would require that this new entity get 100% of its power from renewables, particularly wind and solar, by 2040.  It is similar to a 2001 initiative.

All due respect to PG&E's private property, but I would love to see this happen.  If I were governor, I would be seriously tempted to encourage them to proceed, with the only proviso that no one else in California be allowed to sell electricity to San Francisco on the hugely unlikely possibility that there might be a day without sunshine in San Francisco.   (I find it hilarious that San Francisco's solar future is trumpeted in the "fog city journal.")  This might actually be a big enough disaster that even the media would have trouble ignoring its spectacular failure.  It would also do wonders for the Arizona and Nevada economy, as major industries would move our way.

I am sure San Francisco is well on their way to success.  After all, the city just completed its largest ever solar project. 

            The solar system is expected to generate 370,000 kilowatt hours of
electricity annually, enough to power 80 San Francisco homes.

Wow.  It can power 80 whole homes, as long as its not night time or winter (when it is seldom sunny in SF).

The other day I wrote to beware of rated capacity for wind and solar, because such plants tend to run way below their rated capacity on a 24-hour average.  MaxedOutMamma reads the wind report of the largest utility in Germany, which is as a country is among the largest adopters of wind power.  She finds this interesting bit:

As
wind power capacity rises, the lower availability of the wind farms
determines the reliability of the system as a whole to an ever
increasing extent. Consequently the greater reliability of traditional
power stations becomes increasingly eclipsed.

As
a result, the relative contribution of wind power to the guaranteed
capacity of our supply system up to the year 2020 will fall
continuously to around 4% (FIGURE 7). In concrete terms, this means
that in 2020, with a forecast wind power capacity of over 48,000MW
(Source: dena grid study), 2,000MW of traditional power production can
be replaced by these wind farms.

This is an even lower substitution factor than I mentioned previously, and is so because this report looks not just at the percent of time wind is blowing at full speed, but also at the peak load conventional power plants that must be kept running on standby due to the unreliability of wind.  At this 24:1 substitution ratio, folks like Al Gore and Boone Pickens will bankrupt us.  But of course, their investment portfolios, laden with alt-energy investments, will be paying off.

One needs to be a careful consumer of information when reading about the "rated capacity" of certain alternative energy plants. 

Take a 1MW nuclear plant, run it for 24 hours, and you get 24 MW-hours, or something fairly close to that, of electricity.

Leave 1MW worth of solar panels out in the sun for 24 hours, you get much less total electricity, depending on where you put it.  On an average day in New York City, you will get about 4 MW-hours.  In one of the best solar sites in the word, my home of Phoenix, you get about 6.5 MW-hours per day.  The key metric is peak sun-hours per day, and some example figures are here.  So, even in the best solar sites in the world, solar panels run at only about 25-30% of capacity.

It turns out, not surprisingly, that the same relationship holds for wind.

It's not like it's a secret that wind turbines are an unreliable source of electrical power. Bryce points out that, "In
July 2006, for example, wind turbines in California produced power at
only about 10 percent of their capacity; in Texas, one of the most
promising states for wind energy, the windmills produced electricity at
about 17 percent of their rated capacity."

That means
that there has to be nuclear, coal-fired or natural gas power plants
functioning fulltime as a backup to the pathetically unreliable and
inefficient wind farms. Moreover, what electricity they do generate
is lost to some degree in the process of transmitting it over long
distances to distribution facilities.

Now, this should not outright dissuade us from these technologies, but since no one has really licked the night-time / not-windy storage proble, it's certainly an issue.   I have looked at solar for my house a number of times, and the numbers just are not there (even with up to 50% government subsidies!) without a 2-5x decrease in panel costs.  Low yields can potentially be tolerated, but capital costs are going to have to be a lot lower before they make a ton of sense.

Apparently another interest group is claiming that Arizona is "missing out" on jobs in some critical growth industry, and therefore (wait for it) that industry must be subsidized to come to Arizona.

Arizona is getting its "clock cleaned" in the competition among
Western states to land solar-panel manufacturing companies within their
borders, according to the economic-development group that is losing the
fight.

At least nine companies that make solar equipment have passed up the
Valley of the Sun in the last year in favor of neighboring states,
according to the Greater Phoenix Economic Council.

From those nine projects alone, Arizona is missing out on more than 3,800 jobs, $2.3 billion in investment and $732 million in state and local revenues during the next decade, GPEC President and CEO Barry Broome said.

I am too tired to do my usual fact-checking on "incremental" state revenue numbers, but suffice it to say that $732 million in state and local tax revenues is a pipe dream.  There are three or four million people in Phoenix -- why is it we need the government to focus on someone employing 3,800 people?

The article's main "logic" is that our sunny climate should attract solar panel manufacturers.  Why?  I know they're customers may be here, but since most panels today come to Arizona from Japan or Germany, I don't think shipping costs are a big deal for panels.

The proposal is for a transferable income tax credit and property tax relief.  The author says the group is opposed to straight cash handouts, though.  Uh, OK.  And explain to me why a "transferable income tax credit" that the author says can be sold to other companies for cash is different than a cash handout?

I sometimes find it hard to identify the consistent element of what makes for a "desirable business"  (ie deserving of such subsidies) vs. one that is not so deserving.  The only consistent element I can find is that my business is always in the latter group, paying our taxes so that someone else's business and job can be subsidized.  It is for this reason that I generally barf when some group cries that they are not recieving equal proection (ala the 14th ammendment).  Take on tax and subsidy policy that takes from one group to fund another more politically connected group, and then talk to me about equal protection.

Postscript:  Here are the favored industries I can remember in the news of late in Arizona for getting special tax treatment:

Rock and Roll themed amusement park
Solar panel manufacturing
Neutriceutical production
New shopping mall parking lot
Spring training baseball parks

Readers are encouraged to add others in the comments.

Another Thought: I would dearly love to see a solar panel technology that can be rolled out of the factory cheaply in sheets like carpet out of Dalton, Georgia.  However, while I am increasingly convinced that someone is going to invent that technology soon, that technology will not be related to traditional silicon fabrication methods.  Therefore, nearly all of the plants that Arizona is desperately trying to subsidize to move here are likely using dead-end technologies, driven in part by bubble economics and subsidies that are not sustainable as the market grows (see ethanol).  Current silicon and germanium panels make no economic sense anywhere, and survive only due to massive (50% subsidies) and a desire to make a token green statement.

I am sure our local paper was cheerleading for ethanol plants in years past, and it is good we did not subsidize many here, because they are failing all over.  And I can't prove it, but I wouldn't be a bit surprised that one of the reasons our local semiconductor manufacturing operations have shrunk is because of this same effect, with subsidies attracting the least, not the most, viable enterprises.

A week or so ago, I discussed federal energy subsidies and hypothesized, without a lot of facts, that a lot of them go to failing alternative energy projects rather than to oil company shareholders.  I asked readers if they had any more information, and the discussion is here.

But ask and ye shall receive, and the WSJ has an article today on federal energy subsidies and where they go.  The answer is:  in bulk dollars, a lot of them go nuclear, hydro, and traditional fossil fuel production.  However, it is interesting to look at them on an output basis:

For electricity generation, the EIA concludes that
solar energy is subsidized to the tune of $24.34 per megawatt hour,
wind $23.37 and "clean coal" $29.81. By contrast, normal coal receives
44 cents, natural gas a mere quarter, hydroelectric about 67 cents and
nuclear power $1.59.

The wind and solar lobbies are currently moaning that
they don't get their fair share of the subsidy pie. They also argue
that subsidies per unit of energy are always higher at an early stage
of development, before innovation makes large-scale production
possible. But wind and solar have been on the subsidy take for years,
and they still account for less than 1% of total net electricity
generation. Would it make any difference if the federal subsidy for
wind were $50 per megawatt hour, or even $100? Almost certainly not
without a technological breakthrough.

By contrast, nuclear power provides 20% of U.S. base
electricity production, yet it is subsidized about 15 times less than
wind. We prefer an energy policy that lets markets determine which
energy source dominates. But if you believe in subsidies, then nuclear
power gets a lot more power for the buck than other "alternatives."

The same study also looked at federal subsidies for
non-electrical energy production, such as for fuel. It found that
ethanol and biofuels receive $5.72 per British thermal unit of energy
produced. That compares to $2.82 for solar and $1.35 for refined coal,
but only three cents per BTU for natural gas and other petroleum
liquids.

I will repeat what I said in my earlier post, just so no one is confused about my position:

I personally don't care where [the subsidies go]. I am all for eliminating all
of this subsidy mess, equally, whether it's for oil exploration or
energy-from-donkey-poop or for CEO salary enhancement.

This post from TJIC, which is really about something entirely different, mentions that the price of cocaine has been dropping sharply over the last 10 years.  This is something I have heard police officials lament as well.

Does the profit motive rock or what?  The largest and most powerful government in the world stations armed men and ships around the country.  It has a legal system in place with huge penalties that has of late been nearly entirely dedicated to drug enforcement.  The US has even subverted 200 year old Constitutional restrictions on searches and property seizures (the Patriot Act is mostly used for drug, not terrorism, actions).  All to stop the importation of certain valuable substances.  And even so, the human mind is powerful enough to subvert all of these restrictions and bring in so much supply that the price continues to drop.

Al Gore believes that alternative energy efforts in the US are being subverted by the oil companies:

Apparently, according to Gore, the oil companies drive up prices
reducing supply and then depress them in a telling pattern. As soon as
the political will swells to a light boil, the companies reduce
prices/increase supply.

Really?  Independent drug traders are able to subvert a million government officials with guns to keep cocaine prices low, but Exxon, with a 5% market share (at most) in oil, is able to hold the line on oil supply?

Sure.  In 1972 and 1978 there were a series of oil price shocks (to real levels about where they are today) that convinced everyone that oil prices would keep going up and up and that oil would run out within a few decades.  Of course, in about 1984 oil prices crashed, and stayed down for almost 20 years.  Depending on how you date it, it took oil supply development between 6 and 12 years after the price signal to flood the world with oil, and that was in an environment with price controls and windfall profit taxes that reduced development incentives. 

Right now, we are about 5 years in to the current oil price spike.  Go long at your own risk.

More on supply and demand vs. price manipulation in oil here.  More on Al Gore, including a fisking of his solar plan, here.

Update: Of course, the Democrats in Congress are doing everything possible to keep oil prices up.  If I wanted to ensure high oil prices, I would 1.  Kill incentives to increase supply, perhaps with a "windfall" profits tax and 2.  Put the most promising potential new exploration areas off-limits to new development.  Congressional scorecard:  #2 is in place, and both Obama and Hillary and Pelosi are proposing #1.

Update #2:   Another thought on Gore's statement:  The boom-bust
patterns in oil are characteristic of nearly every other commodity out
there, which therefore presupposes that if oil prices are the result of
manipulation, then every other commodity must be as well since their
prices demonstrate the same patterns.  We see these patterns in
commodities that politicians have never even heard of and in which they
have never thought to exercise their "political will."  (political will
in this context defined as use of government force against a segment of
the populace).

A reasonable person might
suppose that the surge in prices followed by a drop a number of years
later is better explained by the time delay in increasing oil
production after oil prices spike. In many ways, Al's theory is simply
delusional.  If your friend started trying to tell you, in all
seriousness, that every action Microsoft takes is actually aimed at
thwarting him personally, you would think him insane.  But this is
effectively Gore's argument, showing the immensity of the politician's
ego.  Oil prices move not because of supply and demand, but because of
us politicians.  Every tick up and down is carefully managed to thwart
us brave Congressmen!

When a politician describes price signals as mainly influencing political actions, rather than the actions of free producers and consumers, they are probably a socialist.

OK, I buried the lede.  The post is actually not the sex lives of algae.  But I was fascinated that CNN chose to list this among the "story highlights" of this article.  The story supports my sense that if biofuels are ever going to make sense, they are not going to be made from corn.  The story also reinforces the notion that biofuels are just another type of solar energy, though they are in fact even more inefficient than our not-there-yet solar panels in converting sunlight to usable energy.  The only reason biofuels currently look more economic than solar are the enormous operating subsidies and the much lower capital costs  (though even the latter is open to argument since biofuels have huge capital costs in terms of land, but that generally is factored in as "zero" because the land is already being farmed.)

Before you get too excited about algae, note from the picture that the algae at this farm is grown in plastic packets that I would bet my life require more hydrocarbons to produce than the algae inside them provides.

From Steven Milloy:

The audience -- a sold-out crowd of hundreds who had to apply to be admitted and pay a $3,500 fee -- consisted of representatives of the myriad businesses that seek to make a financial killing from climate alarmism. There were representatives of the solar, wind, and biofuel industries that profit from taxpayer mandates and subsidies, representatives from financial services companies that want to trade permits to emit CO2, and public relations and strategic consultants to all of the above.
    
    We libertarians would call such an event a rent-seekers ball -- the vast majority of the audience was there to plot  how they could lock-in profits from government mandates on taxpayers and consumers.
    
    It was an amazing collection of pseudo-entrepreneurs who were absolutely impervious to the scientific and economic facts that ought to deflate the global warming bubble.

    In the interlude between presentations by the CEOs of Dow Chemical and Duke Energy, for example, the audience was shown a slide -- similar to this one -- of the diverging
    relationship between atmospheric CO2 levels and average global temperature since 1998. That slide should have caused jaws to drop and audience members to ponder why anyone is considering regulating CO2 emissions in hopes of taming global climate.

    Instead, it was as if the audience did a collective blink and missed the slide entirely. When I tried to draw attention to the slide during my presentation, it was as if I was speaking in a foreign dialect.

    The only conclusion I could come to was that the audience is so steeped in anticipation of climate profiteering that there is no fact that will cause them to reconsider whether or not manmade global warming is a reality.

But of course we all know that it is the skeptics that are corrupted by money ;=)

I have not ever been able to make solar installation on my house get a reasonable payback, even with rising electricity rates, the best location in the country for solar, and huge government subsidies.  Large solar installations remain a publicity stunt, a sort of really expensive indulgence bought to garner the "green" title:

Scott Gustafson runs the numbers on the solar installation at the revamped Phoenix convention center:

capital cost:  $850,000
operating costs:  not provided
annual electricity savings:  $15,000
return on investment (ignoring operating costs and interest):  1.7%

Solar is still a fine toy for the rich and public figures like Al Gore looking to disguise their true carbon footprint.  But the economics aren't there yet for big boy investors -- its still off by an order of magnitude, at least.

Hopefully, this will change as high energy prices encourage innovation.

Every 2-3 years I do the math on solar cells for my home.  I live in a house with a large flat roof and in one of the top 10 cities in the world for solar potential, so it seems to make sense in theory.  Unfortunately, even with large government / power company subsidies, the math never works as an investment.

The problem for me is not efficiency - I have enough flat space on my roof for a lot of cells - but cost.  We need a solar technology that can be rolled out of the factory like carpet from Dalton, Georgia.  To this end, this looks promising.

I couldn't make the return on investment
(even with a 50% government subsidy and in one of the best solar sites
in the world) work for solar on my home in Phoenix, at least at current
prices and technology.  Maybe I can justify a backyard nuclear reactor?

Hat tip:  Another Weird SF Fan

I turned off comments on the published HTML version of my Skeptical Layman's Guide to Man-made Global Warming    (pdf here) to avoid spam problems.  However, it was not my intention to forgo the ability of readers to comment.  So I am going to link this comment thread from the bottom of each chapter.

I have gotten several comments back similar to what Steven Dutch says here:

So You Still Don't Believe In Global Warming?

Fine. Here's what you have to do....

• Show conclusively that an increase in carbon dioxide will
  not result in global warming. Pointing to flaws in the climate models,
  possible alternative explanations, and unanswered questions won't cut it. We
  know carbon dioxide traps infrared and we know climate is
  getting warmer. There's a plausible cause and effect relationship there. You
  have to show there is not a causal link. You can do that either by
  identifying what is the cause ("might be" or "possible alternative"
  isn't good enough) or by showing that somehow extra carbon dioxide does
  not trap solar heat.

This might be correct if we were in a college debating society, where the question at hand was "does man contribute to global warming?"  However, we are in a real world policy debate, where the question is instead "Is man causing enough warming and thereby contributing to sufficiently dire consequences to justify massive interventions into the world economy, carrying enormous costs and demonstrable erosions in individual freedoms."  Remember, we know monetary and liberty costs of abatement with a fair amount of cerntainty, so in fact the burden of proof is on man-made global warming advocates, not skeptics, who need to prove the dangers from the man-made component of global warming outweigh the costs of these abatements.

That is why the premise for my paper is as follows:

There is no doubt that CO2 is a
greenhouse gas, and it is pretty clear that CO2 produced by man has an
incremental impact on warming the Earth's surface. 

However, recent
warming is the result of many natural and man-made factors, and it is
extraordinarily difficult to assign all the blame for current warming to
man. 

In turn, there are very good reasons to suspect that climate
modelers may be greatly exaggerating future warming due to man.  Poor
economic forecasting, faulty assumptions about past and current conditions, and
a belief that climate is driven by runaway positive feedback effects all
contribute to this exaggeration. 

As a result, warming due to man's
impacts over the next 100 years may well be closer to one degree C than the
forecasted six to eight.  In either case, since AGW supporters tend to grossly
underestimate the cost of CO2 abatement, particularly in lost wealth creation
in poorer nations, there are good arguments that a warmer but richer world,
where aggressive CO2 abatement is not pursued, may be the better end state than
a poor but cooler world.

Interventionists understand that their job is not to prove that man is causing some global warming, but to prove that man is doing enough damage to justify massive economic interventions.  That is why Al Gore says tornadoes are increasing when they are not, or why he says sea levels will rise 20 feet when even the IPCC says a foot and a half.  And I will leave you with this quote
from National Center for Atmospheric Research (NOAA) climate researcher and
global warming action promoter, Steven Schneider:

We have to
offer up scary scenarios, make simplified, dramatic statements, and make little
mention of any doubts we have. Each of us has to decide what the right balance
is between being effective and being honest.

Comment away.  I don't edit or delete comments, except in the cases of obvious spam.

Update:  Here is another reason why there is an important difference between "man causes any warming at all" and "man causes most of the warming."

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. 

In the past, I have argued that it is odd that climate scientists ignore the changes in solar activity in their models.  Despite the fact the sun's activity is at a very high level (vs. the past several hundred years) the most recent IPCC report says they think that earth's temperatures would have fallen in the 20th century absent anthropogenic effects.  So then why is this happening:

Mars is being hit by rapid climate change and it is happening so fast that the red planet could lose its southern ice cap,
writes Jonathan Leake.

Scientists from Nasa say that Mars has warmed by about 0.5C
since the 1970s. This is similar to the warming experienced on Earth
over approximately the same period.

Since there is no known life on Mars it suggests rapid changes in planetary climates could be natural phenomena.

The
mechanism at work on Mars appears, however, to be different from that
on Earth. One of the researchers, Lori Fenton, believes variations in
radiation and temperature across the surface of the Red Planet are
generating strong winds.

In
a paper published in the journal Nature, she suggests that such winds
can stir up giant dust storms, trapping heat and raising the planet's
temperature.

Almost every planet in the Solar System has been found to be warming over the last several decades.  At what point do we turn our attention, at least in part, to Mr. Sun?  (Hat tip Q&O Blog)

Anybody who has been a part of a productive business (e.g. so this excludes almost all politicians and academics) will probably have experience with some type of profit improvement program.  Usually you are doing about a hundred things simultaneously to reduce costs.  When costs actually go down, you find yourself scratching you head - what actually made the difference.  Everyone will claim that their program or initiatives saved the company X amount of money, but when you add up all the X's, you get a number four or five times the actual improvement. 

Well, apparently the same dynamic occurs in carbon offsets:

An investigation by the Financial Times
suggests that many carbon offsets are illusory, and that there is
little assurance that purchasing carbon offsets does much of anything
to reduce carbon dioxide emissions. Specifically, the report found:

-
Widespread instances of people and organisations buying worthless
credits that do not yield any reductions in carbon emissions.

- Industrial companies profiting from doing very little "“ or from
gaining carbon credits on the basis of efficiency gains from which they
have already benefited substantially.

- Brokers providing services of questionable or no value.

- A shortage of verification, making it difficult for buyers to assess the true value of carbon credits.

Who in the world would have every predicted this?  Well, it turns out a lot of people did, including me.  For example, I suggested that companies like Terrapass are probably selling their CO2 offsets at least three times:

1. Their energy projects produce electricity, which they sell to
   consumers.  Since the
   electricity is often expensive, they sell it as "CO2-free"
   electricity.  This is possible in some sates -- for example in Texas,
   where Whole Foods made headlines by buying only CO2-free power.  So the
   carbon offset is in the bundle that they sell to
   electricity customers.  That is sale number one. 
2. The company most assuredly seeks out and gets
   government subsidies.  These subsidies are based on the power being
   "CO2-free".  This is sale number two, in exchange for subsidies. 
3. They still have to finance the initial construction of the plant, though.  Regular heartless
   investors require a, you know, return on capital.  So Terrapass
   finances their projects in part by selling these little certificates that you
   saw at the Oscars.  This is a way of financing their plants from people
   to whom they don't have to pay dividends or interest "”just the feel-good
   sense of abatement.  This is the third sale of the carbon credits.

I also suggested that there is an incredible opportunity for outright fraud:

This type of thing is incredibly amenable to fraud.  If you sell more
than 100% of an investment, eventually the day of reckoning will come
when you can't pay everyone their shares (a la the Producers).  But if
people are investing in CO2 abatement -- you can sell the same ton over
and over and no one will ever know.

Finally I argued that many of the abatement numbers make no sense:

Something smells here, and it is not the cow-poop methane.  This 100,000 pound [CO2 Offset] coupon retails for $399.75 (5x79.95) on the TerraPass web site.
First, this rate implies that all 300 million Americans could offset
their CO2 emissions for about $100 billion a year, a ridiculously low
figure that would be great news if true. 

Lets look at solar, something I know because I live in Arizona and have looked at it a few times.  Here is the smallest, cheapest installation
I can find.  It produces 295 CO2-free Kw-hours in a month if you live
in Phoenix, less everywhere else.  That is enough to run one PC 24
hours a day -- and nothing else.  Or, it is enough to run about 10
75-watt light bulbs 12 hours a day -- and nothing else.  In other
words, it is way, way, way short of powering up a star's Beverly Hills
mansion, not to mention their car and private jet.  It would not run
one of the air conditioning units on my house.  And it costs $12,000!
Even with a 20 year life and a 0% discount rate, that still is more
than $399.75 a year.  For TerraPass's offset claim to be correct, they
have to have a technology that is one and probably two orders of
magnitude more efficient than solar in Arizona.

[update:  Al Gore's house 221,000 kwH last year.  Call it 18,400KwH
per month, that would require about 62 of these solar installations for
$744,000.  I don't think $399.75 is really offsetting it]

Until I watched the Global Warming Swindle, I had confined my criticisms of anthropogenic global warming theory to two general areas:  1)  The models for future warming are overstated and 2) The costs of warming may not justify the costs of preventing it.

The movie offered an alternate hypothesis about global warming and climate change that, rather than refute the magnitude of anthropogenic global warming, provided a counter hypothesis.  You should watch the movie, but the counter hypothesis is that historic temperature changes have been the result of variations in solar activity.  Rather than causing these changes, increased atmospheric CO2 levels resulted from these temperature increases, as rising ocean temperatures caused CO2 to be driven out of solution from the world's oceans.

I thought one of the more compelling charts from Al Gore's pPwerpoint deck, which made the movie An Invconvienent Truth, was the hundred thousand year close relationship between atmospheric CO2 levels and global temperature, as discovered in ice core analysis.  The Swindle movie, however, claims that Gore is hiding something from that analysis in the scale of his chart -- that the same ice core analyses show that global temperature changes have led CO2 concentration changes by as much as 800 years.  (short 2-minute snippet of this part of the movie here, highly recommended).

Well, this would certainly be something important to sort out.  I have not done much real science since my physics days at Princeton, but my sense is that, except maybe at the quantum level, when B follows A it is hard to argue that B caused A.

So I have poked around a bit to see -- is this really what the ice core data shows, or is Swindle just making up facts or taking facts out of context ala the truther hypotheses about 9/11?  Well, it turns out that everyone, even the die-hard global warming supporters, accept this 800-year lag as correct (Watch the Al Gore clip above -- it is clear he knows. You can tell by the very careful way he describes the relationship).  LuboÃ…¡ Motl summarizes in his blog:

However, the most popular - and the most straightforward - explanation
of the direction of the causal relationship is the fact that in all
cases, the CO2 concentration only changed its trend roughly 800 years
after temperature had done the same thing. There have been many papers
that showed this fact and incidentally, no one seems to disagree with
it....

The whole "group" at RealClimate.ORG
[ed: one of the leading sites promoting the anthropogenic theory] has agreed that there was a lag. But they say that in the first 800
years when the influence of temperature on CO2 is manifest, it was
indeed temperature that drove the gases. But in the remaining 4200
years of the trend, it was surely the other way around: CO2 escalated
the warming, they say.

Frequent readers will know that I have criticized forward looking climate models on many occasions for being too reliant on positive feedback processes.  For example, in the most recent IPCC models, over 2/3 of future warming come not from CO2 but from various positive feedback effects (section 8.6 of the 2007 report). 

The folks at RealClimate.org are similarly positing a positive feedback mechanism in the past -- "something" causes initial warming, which drives CO2 to outgas from the oceans, which causes more warming, etc. 

I am not sure I have ever done so, so 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 (except, apparently, on the greens at Augusta).  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, 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.

Back to the climate question.  The anthropogenic guys are saying that when the earth heated, it caused CO2 to outgas from the oceans, which in turn caused more warming, which causes more outgassing, etc.  But where does it stop?  If this is really how things work, why isn't the Earth more like Venus?  If you are going to posit such a runaway process, you have to also posit what stops it.  So far, the only thing I can think of is that the process would stop when the all bands of light that are absorbable by CO2 are fully saturated.

But the feedback is worse than this.  I won't go into it now, but as you can see from this post, or from section 8.6 of the 2007 IPCC report, the current climate models assume that warming from CO2 itself yields further positive feedback effects (e.g. more humidity) that further accelerate warming, acting as a multiplier as great as 3-times on CO2 effects alone.

So here is the RealClimate view of the world:  Any small warming from some outside source (think Mr. Sun) is accelerated by outgassing CO2 which is in turn accelerated by these other effects in their climate models.  In other words, global temperature is a ball sitting perched on the top of a mountain, and the smallest nudge causes it to accelerate away.  This is the point at which, despite having only limited knowledge about the climate, I have to call bullshit!  There is just no way our planet's climate could be as stable as it has been long-term and be built on such positive feedback loops.  No way.  Either these folks are over-estimating the positive feedback or ignoring negative feedbacks or both.  (and yes, I know we have had ice ages and such but against the backdrop of the range of temperatures the Earth theoretically could have in different situations, our climate variation has been small).

Postscript:  The other day I mentioned that it was funny a group studying solar output felt the need to put in a statement validating anthropogenic global warming despite the fact that nothing in their research said any such thing.  Motl points to a similar thing in the ice core studies:

Well, the website tells us that the paper that reported the lag contained the following sentence:

• ...
  is still in full agreement with the idea that CO2 plays, through its
  greenhouse effect, a key role in amplifying the initial orbital forcing
  ...

Again, this statement was included despite the fact that their study pretty clearly refutes some key premises in anthropogenic global warming theory.  It's become a phrase like "no animal was hurt in the filming of this movie" that you have to append to every climate study.  Or, probably a better analogy, it is like Copernicus spending a few chapters assuring everyone he still believes in God and the Bible before he lays out his heliocentric view of the solar system. 

Update: All this is not to say that there are not positive feedback loops in climate.  Ice albedo is probably one -- as temperatures rise, ice melts and less sunlight is reflected back into space by the ice so the world warms more.  My point is that it does not make any sense to say that positive feedback processes dominate.

Correction: Like a moron, I have been using anthropomorphic rather than anthropogenic to refer to man-made climate effects.  Oops.  Thanks to my reader who corrected me.  I have fixed this article but am too lazy to go back and edit the past.

Further Update:  The irony of my correction above juxtaposed against the title of the previous post is not lost on me.

Update to the Postscript: Oh my god, here it is again.  An NOAA-funded study comes to the conclusion that global warming might actually reduce hurricane strength and frequency.  Nowhere in the study did the researchers touch any topic related to anthropogenic warming -- they just studied what might happen to hurricanes if the world warms for any reason.  But here is that disclaimer again:

"This study does not, in any way, undermine the widespread consensus in the scientific community about the reality of global warming," said co-author Brian Soden, Rosenstiel School associate professor of meteorology and physical oceanography whose research is partly funded by NOAA.

Does the NOAA and other funding bodies actually require that this boilerplate be added to every study?

Via Jane Galt:

The environmental movement has so far utterly failed to develop a
coherent approach to replacing carbon producing power sources. Wind and
solar are not such a coherent response without a massive breakthrough
in battery technology, because variable sources are inadequate to
provide base-load power. Also, they too have negative externalities:
wind kills birds and destroys views, and many solar panels are loaded
with gallium arsenide, a highly toxic substance that is apparently
rather tricky to dispose of.

All this wouldn't be so bothersome if the environmental movement
merely failed to provide realistic alternatives, but in fact, many
environmentalists actively move to block new wind installations (I'm
looking at you, Robert jr.) and nuclear power plants, spread hysteria
over nuclear waste, and otherwise actively work against the cause they
are trying to advance. As such, it is perfectly legitimate to demand
why they are blocking the only things that have any realistic chance of
replacing carbon-emitting power plants.

The answer, in my opinion, is that too many environmentalists flunk
basic and economic knowlege, which is why so many people believe it is
practical to replace a coal-fired turbine that pumps out 1,000
megawatts with a solar installation that will, in peak sun conditions,
produce about 1 kilowatt per 150 feet of space, twelve hours a day; or
wind farms, which average less than 1 megawatt per turbine in prime
spots. In addition, the core of the environmental movement are people
with a whole host of linked views about things like capitalism,
consumer culture, and so forth; they find solutions that support,
rather than changing, the existing system much less emotionally
interesting than radical conservation strategies. Unfortunately, the
latter are a thoroughgoing political failure, but the environmental
movement has strenuously resisted adjusting to this reality. (Some
leaders have, God bless them). As long as this attitude persists, the
environmental movement is blocking change that could and should happen;
it is perfectly legitimate, nay necessary, to tax them on this.

She only sortof answers her own question at the end.  The real answer is that many who currently lead the environmental movement don't want a technological fix that sustains economic growth without CO2 emissions.  The whole point of latching onto, and exaggerating, the theory of anthropomorphic global warming is to find a big new club to bash capitalism and wealth.  Just watch this segment of Penn & Teller's Bullshit! where film of environmental movements is shown.  All the rhetoric is not anti-polluter, it's anti-corprorate and anti-capitalism.  Many leading environmentalists want nothing less than to shut down the global economy, and if that means taking down every poor person in the world just to get at Exxon and General Motors, they are willing to do so.

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.

Of course, these poor scientists know that they could lose their jobs and be called Holocaust deniers if they don't acknowledge anthropomorphic global warming, so they do say:

Over the past 20 years, however, the number of
sunspots has remained roughly constant, yet the average temperature of
the Earth has continued to increase.

This is put down to a human-produced greenhouse effect caused by the combustion of fossil fuels.             (HT:  TJIC)

Which may actually be the case, but it is interesting that astronomers feel the need to say this without any evidence of such in their own study just to protect themselves from ostracism by the climate religionists.

However, even if the two are working in concert, the fact that solar activity explains some of the 20th century warming means that current climate models are WAY overestimating the impact of anthropomorphic warming. 

For example, the climate models in the current 2007 IPCC report assume that the world would have experienced no warming in the 20th century without man.  This is from Section 8, actual is the black line, the models without man are in blue, the models with man are in red:

In other words, the IPCC models completely ignore the increasing solar activity and assume 100% of 20th century warming was due to man-made effects, even the substantial warming before 1940 (and before the onset of truly heavy world-wide fossil fuel use).

Already, the models used by the IPCC tend to overestimate past warming even if all past warming is attributable to anthropomorphic causes.  If anthropomorphic 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.

Postscript: I cannot prove this, but I am willing to make a bet based on my long, long history of modeling (computers, not fashion).  My guess is that the blue band, representing climate without man-made effects, was not based on any real science but was instead a plug.  In other words, they took their models and actual temperatures and then said "what would the climate without man have to look like for our models to be correct."  There are at least four reasons I strongly suspect this to be true:

1. Every computer modeler in history has tried this trick to make their models of the future seem more credible.  I don't think the climate guys are immune.
2. There is no way their models, with our current state of knowledge about the climate, match reality that well. 
3. The first time they ran their models vs. history, they did not match at all.  This current close match is the result of a bunch of tweaking that has little impact on the model's predictive ability but forces it to match history better.  For example, early runs had the forecast run right up from the 1940 peak to temperatures way above what we see today.
4. The blue line totally ignores any of our other understandings about the changing climate, including the changing intensity of the sun.  It is conveniently exactly what is necessary to make the pink line match history.  In fact, against all evidence, note the blue band falls over the century.  This is because the models were pushing the temperature up faster than we have seen it rise historically, so the modelers needed a negative plug to make the numbers look nice.

I finally watched the BBC special Global Warming Swindle and have to say that it presents a pretty good counter-hypothesis to the prevailing theory of anthropomorphic CO2 production to explain recent global temperature changes.  It also hits some good points on what might be motivating the hard core of the environmental movement beyond just concern about global warming, and why the costs of CO2 control are so high.

I have historically accepted the basic hypothesis of anthropomorphic global warming but have been skeptical of the exaggerated outcomes (Al Gore's 26 foot sea-level rise, for example, which is 17 times more than even the IPCC predicts over the next century) and have posited that a warmer but richer world may well be better than a cooler but poorer one.  I have also pointed out the uncertainties in the IPCC analysis that never get mentioned in the press, like the huge uncertainty in the feedback loops that drive much of the temperature change in current models.  For example, the IPCC admits they don't even know the sign of the largest feedback loop (clouds), which is a big uncertainty since about 2/3 or more of the warming in the models come not directly from CO2 but from these feedback loops.

Anyway, most of my past skepticism has been within the framework of these IPCC studies.  However, this documentary casts off the whole framework, offering a counter-hypothesis of solar activity to explain temperature variations.  I thought the most interesting part of the documentary was when they showed Al Gore from An Inconvenient Truth with a multi-thousand year plot of temperature and CO2.  The chart certainly looks compelling, but this movie makes the point that while the two lines move together, the CO2 line is lagging the temperature line by five hundred years.  Meaning that CO2 levels may be linked to temperature, but the causality may be opposite of that implied by Gore. 

The documentary goes on to offer solar activity as an alternative explanation, with graphs of moving curves of solar activity and temperature that seem to show at least as much correlation as Gore's CO2 graphs.  They hypothesize that rising temperatures driven by changes in solar
activity heat up oceans over time and cause them to release CO2 into
the atmosphere.  I don't think the evidence is definitive, but it certainly casts doubt as to whether we really know what is going on.  I always thought it a bit odd that people would search for the causes of changing temperatures without first checking out the sun, sortof like walking in a room that is too hot and trying to fix it without first checking the thermostat.  This is particularly true given new evidence that other planets are warming, presumably due to solar activity (unless, of course, it's an Exxon plot).

By the way:  Advocates of the anthropomorphic theory are criticizing this movie in part because it does not use Mann's hockey stick temperature chart.  Sorry, but if they want to claim the scientific high ground, I think they need to stop tying their argument to this weak study.  Statisticians have dumped on it repeatedly (apparently random white noise fed into their model produces a hockey stick) and the evidence for eliminating the Medieval warm period is based on the rings in one or two trees.