Arnold Kling  

Global Warming and CO2

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Mathematician David Evans writes,


After further research, new high-resolution ice core results (data points only a few hundred years apart) in 2000–2003 allowed us to distinguish which came first, the temperature rises or the CO2 rises. We found that temperature changes preceded CO2 changes by an average of 800 years. So temperature caused the CO2 levels, and not the other way around as previously assumed. The world should have started backpedaling away from blaming carbon emissions in 2003.

...As of August 2007, we've measured where the warming is occurring in a fair bit of detail, using satellites and balloons. The observed signature is nothing like the greenhouse signature. The distinct greenhouse signature is entirely missing:

There is no hotspot in the tropics at 10 km up, so now we know that greenhouse warming is not the (main) cause of global warming — so we know that carbon emissions are not the (main) cause of global warming.

...Doubling atmospheric CO2 from the pre-industrial level of 280ppm up to 560ppm (which is roughly were the IPCC says we will be in 2100) is calculated to raise the world's air temperature by 1.2C in the absence of feedbacks such as convection and clouds. This is what you would get if the air was in a flask in a laboratory. Everyone roughly agrees with that calculated result.

But the modelers assumed (bad assumption #2) that increased warming would cause more rainfall, which would cause more clouds high up in the atmosphere — and since high clouds have a net warming effect, this would cause more warming and thus more rainfall and so on. It is this positive feedback that causes the UN climate models to predict a temperature rise due to a rise in CO2 to 560ppm to be 2.5C - 4.7C (of which we have already experienced 0.7C).

But in September 2007, Spencer, who spent a few years observing the temperatures, clouds, and rainfall, reported that warming is actually associated with fewer high clouds. So the observed feedback is actually negative, so we won't even get the full 1.2C of greenhouse warming even if carbon levels double!


I assume that the global warming believers have a rational response. Perhaps the alleged evidence cited above is wrong. Perhaps it is right, but not as important as other evidence that should increase our confidence that CO2 is causing global warming.


Comments and Sharing





COMMENTS (32 to date)
z writes:

If the climatologists can't accurately predict what the weekend weather is going to be like, why would anyone lend credence to predictions 20, 50, and 90 years into the future?

MK writes:

Sorry, but that's really boring - and it's easy:
What does the lag of CO2 behind temperature in ice cores tell us about global warming?

You are an economist (and so am I). So perhaps you should stop quarreling with the evidence without any real knowledge. Do I want to hear an antrophologist, chemist or physicist on exchange rate policies? NO! Do I want to hear an economist on climate science? NO! I want to hear a climate scientist...

So for the next time why not start here, or directly have a look at the most common climate myths? Or try to get it in 6 easy steps?

... or what about just reading The Economist? (They did a whole Survey on the topic in the Sept 7th 2006 issue)

In the next post about climate change I want to read something about external effects, property rights(?) or the economics of cap & trade - and no more pseudo-science.

(Besides this point I *love* your blog - just to make sure I am not mistaken)

MK writes:

Addendum:

Did anybody hear about this "1% Doctrine"? Well, I think it's b***s*** - but there is a point: If there is a threat we should act on it. We shouldn't take a 1% threat as if it was a "slam dunk" - but we should take it as what it is: A 1% probability of a very harmful event.

And of course the same should apply to climate change: Will Florida disappear? Probably not - but is there a serious probability of very harmful and costly effects if we don't act? If we ask climate scientists rather than economists or politicians they tell us: YES there is .. So we should *ACT* on it - accordingly to the probability and the expected costs. That's economics 101 - I think I will never get what's so hard to comprehend about it for some...

Tom writes:

MK, you don't cite any better evidence than Arnold's link does. Repeating an argument does not prove it.

Regarding:"Do I want to hear an antrophologist, chemist or physicist on exchange rate policies? NO!"
Most of the pro-AGW claims made that have been proven to be false (Hansen's 1998 hottest year, Mann's hockey stick) were made because either elementary mistakes in or abuse of statistical methods. Economists are actually better versed in stats than the scientists.

The fact that both of the men would not voluntarily show the data behind their results also speaks very poorly of them.

Josh writes:

MK - the first RealClimate post should alert you that something is WRONG. It's a bunch of hand-waving, especially compared to their usual cite-the-peer-reviewed-journal style. To summarize their conclusion: CO2 lags temp by 800 years but warm spells last 5000. Therefore, they claim, we can conclude that something causes temps to rise and then CO2 800 years later, after which CO2 drives temps for the next 4200 years(!!). What was it friar Ockham said about the simplest solution usually being the best? Wouldn't it be a reduced-complexity solution to ignore any effect of CO2 on temperature and simply assume that the initial driver is the only driver? Especially given that the temperature goes back down despite the elevated CO2 levels.

Bob Hawkins writes:

I'm just surprised that the journal didn't reject this paper on grounds that everyone knew this already.

The details of how the warming is distributed, geographically and historically as well as in altitude, have always contradicted the greenhouse hypothesis. The greenhouse pushers have in the past dealt with the problem in this way:

1. Ignore it as long as possible.
2. Fob it off with some handwaving as long as possible.
3. Convene a panel on "reconciling observations" where every nitpicking effect that might make the nonconforming temperatures move toward conformance is considered, but the conforming temperatures are not even looked at. When you're done, declare that all the problems have been resolved even though they haven't. Go to Step 1.

They've been forced to Step 3 twice now. (A previous reply suggests we are now on Step 2 for the third time.) I once served on a "reconciling observations" panel on another topic, and I must say I see nothing surprising in the reports from these two. That is not a compliment.

The reason the current paper concentrates on the tropical troposphere, is that that is where the second panel totally failed to fudge, er correct, the nonconforming data. It reported complete success anyway, of course.

First reconciling report:
http://www.nap.edu/openbook.php?isbn=0309068916

Second reconciling report:
http://www.climatescience.gov/Library/sap/sap1-1/finalreport/default.htm

Mace writes:

MK,

Thanks for the link that explains the lag between CO2 and warming. I'm fairly well-read but had never heard of it before. A lot of the GW debate is like this.

The real question is why the Global Warming Community has not had high-profile public debate on the many issues raised by the many dissenters. Instead, we have name-calling along the lines of "GW deniers." It's as if such a debate would somehow reduce their case, or perhaps "lower" themselves. Instead, the public is supposed to be convinced by Al Gore's "Inconvenient Truth", which in my opinion is laughably bad on the facts and the science. It feels more like a Gore campaign commercial.

So the GWC has a lot more work to do, perhaps in the PR department. After all, extraordinary claims require extraordinary evidence. If the problem is as serious as the GWC claims, then they ought to have all the motivation in the world. Otherwise, it just feels like a Leftist power grab.

Ben Kalafut writes:

Why "assume" that they have such evidence or arguments, but not even bother to seek it out.

If you're going to be a "climate skeptic", you're either in--which means you have to do your homework--or you're out.

8 writes:

MK,

First you say economists shouldn't explain science and scientists shouldn't explain economics, but then you say we should act because of a 1% chance of disaster. Scientists can give a very rough probability of an event, but economists will tell you how much it will cost. From what I've read, the costs of acting—as defined by what environmentalists want— are still higher than doing nothing and dealing with the problems when they occur.

Peter Twieg writes:

I find it particularly amusing that a blog run by "a big defender of experts" (see above post) has such a feisty crowd of contrarian armchair climatologists. Amusing, but hardly surprising.

I'm sure over on Bizarro EconLog Caplan is getting accolades for his publishing The Myth of the Rational Voter (revealing voters' systematically biased beliefs on environmental issues) and the commentators are blasting the failure of leading economists to engage in a high-profile debate over the merits of an open immigration policy at this very moment: "If the economists can't accurately predict what the DOW is going to be like, why would anyone lend credence to predictions 20, 50, and 90 years into the future?"

I don't mean to troll here, but I do find this to be an interesting vignette of a larger meta-issue.

Ben Kalafut writes:

Worth noting, btw, is that Evans' glib position that, as of 2007, we know "know for sure that greenhouse is not causing global warming. CO2 is no longer suspect" is not being manifested in the the current technical literature, nor in the meta-scientific discussion. To be clear, neither the position that the Greenhouse Effect (which results from multiple gases...) is not causing the observed warming, nor the position that CO2 is a major culprit in anthropogenic perturbation of the radiation balance, have as of 2007, become
the new status quo.

Worth noting also is that this is the old "CO2 doesn't lead, it lags" misuse-of-Milankovitch Cycle argument. It centers on two fallacies:

(1) The current warming phenomenon must be the same as warming that happenened thousands or tens of thousands of years ago. It's rather clear that the AGW thesis is that the causes of today's warmnig are not the same as non-anthropogenic past warmings.

(2) A short time-scale warming can be explained by the same mechanism as long time-scale warming. That cute oscillatory graph that the denialists like to shop around doesn't do them any favors, unless the audience is easily hoodwinked, as it doesn't carry with it the argument "and our current warming fits the cycle right here." Nor are the denialists even bothering to make the argument. They either don't understand what they're presenting, or are counting on you being a sucker. An astute observer will look to the tail end of the graph and see that the temperature trend has been off-cycle since, roughly, the Neolithic or Epipaleolithic, when Man significantly altered methane atmospheric methane concentrations and perturbed CO2 through deforestation.

If you'd have bothered to do a little digging, you'd have found a rather satisfactory response. Let's start with Evans's reference. To quote:
"These results fit well with the standard explanation for the Ice Ages, which is that an initial temperature trigger (for example, changes in the earth's orbit), result in release of CO2 and other greenhouse gases to the atmosphere (for example, release of CO2 from the ocean as it warms). As the greenhouse gas concentration in the atmosphere builds up, it results in more warming and further release of greenhouse gases (i.e. a feedback cycle)."

You can go to RealClimate for a discussion of this matter by working climatologists. Perhaps that would be a better place to start, than to get your climatology fix from the promoters of the economic equivalent of Freudian psychology, humoral theory of physiology, or the phlogiston theory of heat.

JMG3Y writes:

The climate science community's rational "response" would be the "IPCC Fourth Assessment Report" at:
http://www.ipcc.ch/ipccreports/index.htm

Working Group I Report "The Physical Science Basis" deals with the evidence for climate change
http://www.ipcc.ch/ipccreports/ar4-wg1.htm

Within this group's report, the issue appears to be addressed here: Chapter 6 Palaeoclimate
http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter6.pdf

Rimfax writes:

MK,

The hypothesis that the CO2 might cause the further warming after the first 800 years is a interesting idea. Some evidence supporting it would have been nice.

If indeed it does cause further warning, why do the global temperatures ever rebound. I mean, if warming causes CO2 release and CO2 causes further warming, why isn't the Earth stuck in a Venusian equilibrium rather than a Terran equilibrium?

For this hypothesis to fit Earth's history, there would have to be a peak for the warming/CO2 trend where the Earth's temperatures sat in a new, warmer equilibrium. The temperatures of this warmer equilibrium would have to be low enough for a volcanic catastrophe to break and reverse to the lower "normal" temperature equilibrium that we are familiar with.

Is there any historical or scientific evidence to suggest that warming and CO2 levels boost each other to a new warmer equilibrium level beyond which more warming or higher CO2 concentrations work against each other? Without such an equilibrium, either the Earth's climate has been astronomically lucky or the hypothesis doesn't hold.

Ben Kalafut writes:

Surely, Z in #1 and 2, you must be joking.

But for those on whom the joke is lost: predicting the *weather* is a problem wholly different from predicting the *climate*. The climate is not modeled by simply integrating the weather models for a longer time period. (Regarding the weather, though, have you noticed that they've gotten quite good at quite many things, among them hurricane track forcasting?)

Rimfax writes:

Ben Kalafut,

If historical warming led to higher CO2, and current increases in CO2 are causing warming, how did the Earth ever recover in the past?

I can accept that the modern CO2 increases are unprecedented and that mid-century anthropogenic precipitate levels may have masked warming effects, but if the historical evidence indicates T increases C, how can I believe that C increases T without wondering how this system managed to repeatedly return to equilibrium for so many millenia?

nilincic writes:

JMG3Y writes:
"Within this group's report, the issue appears to be addressed here: Chapter 6 Palaeoclimate
http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter6.pdf" - can you please point me to the page where the issue is addressed - I do not see anything relevant in the TOC.

Ben Kalafut writes: "..."
Let's keep the temperature of the discussion down. There are two issues, second of which you ignored:

- new, more precise analysis of ice cores shows that CO2 level rise trails T rise. If that was always the case historically, it follows that CO2 rise *cannot* cause T increase. Why? Beacuse it it could, we would see another T jump after CO2 level has increased (because of a previous T jump, for example). We do not see that.

- atmospheric signature of T rise does not correspond to one predicted by "CO2 causes T rise" hypothesis.

Any arguments on this, other than name-calling?

Dr. T writes:

My credentials: chemist, pathologist, statistician

Points:

1. The 'greenhouse effect' is not relevant for our planet. The greenhouse effect gases (95% from water vapor and less than 5% from CO2) got their label because they cause increased temperatures in sealed environments (greenhouses). However, our planet is not a greenhouse, it is a huge, open system. There is no reliable evidence that CO2 exerts a warming effect on the planet.

2. The water in oceans and lakes acts as a sponge for atmospheric CO2. Cool water holds more CO2 than warm. When the earth warms up, oceanic CO2 levels decline due to outgassing and atmospheric CO2 levels rise. This is basic chemistry and does not require a PhD in climatology to understand.

3. Given point 2, it is not surprising that studies of ice cores show that atmospheric CO2 levels increase after periods of global warming.

4. The IPCC studies are not scientific proof of anything. Read them yourself to see how bad they are. Here's an example of IPCC spin: The IPCC looked at 24 climate models. None could predict known climate from 1990-2000 after being fed data from the previous 100 years or so. The IPCC merged these flawed models to create a meta-model. The IPCC bragged that its meta-model predicted mean annual temperatures within 2 degrees centigrade in 95% of the earth's zones. Since much of the earth has very stable mean temperatures, that's not much of an accomplishment. What the IPCC fails to point out is that the meta-model was least accurate near the poles. In fact, the meta-model's predicted mean annual temperatures for the polar zones were 6 degrees centrigrade too high! Despite this known flaw, the IPCC used this meta-model used to predict global warming, ice cap melting, coastal flooding, etc. The IPCC deliberately lied.

5. No one has shown that global warming, whether anthropogenic or not, is bad. Perhaps the net effects will be positive. Delaying the next ice age would be a huge positive. Glaciers sweeping down from the Arctic to cover all of Canada and half of the U.S., Europe, and Russia would be much more damaging than rising sea levels. We can build dikes and levees, we cannot divert continent-sized glaciers.

Douglass Holmes writes:

Although I consider myself a skeptic of AGW, I do find it interesting to compare the theory of AGW with the minimum wage. The majority of climate scientists believe in Anthropogenic Global Warming theory, but there are a few qualified scientists who voice skepticism. Which experts are we to believe?
Likewise, the majority of economists believe that minimum wage laws are meaningless at best and probably harmful to the economy. But, each time a minimum wage increase in proposed, you can find quite a few economists arguing in favor of the increase. Again, which experts should we believe?

Economics is the study of the allocation of scarce resources. So, economists should be very interested in how we solve this problem or if it is even a big enough problem to solve. I am quite willing to concede AGW but still oppose the Kyoto treaty. The benefits have to exceed the costs.

frank cross writes:

Isn't there some irony in the juxtaposition of a defense of the opinion of experts and the refusal to accept the expert opinion on climate? Or is it only economics experts that merit deference?

I rather fear the blog authors are succumbing to the tendency of the public to reject expert opinions that are inconvenient to them.

Brad Hutchings writes:

Douglas, Great point. My belief is that if climate scientists who are worried about AGW want to affect policy, then they need to make their science more available and verifiable by those outside their field. Right now, it's all politics and a giant shouting match, which is enough reason to believe that the scientists advocating anything from CO2 controls to growing funding are some percentage of full of beans. The only verifiable reality in this is that AGW has become a political catch-all about awareness and drowning polar bears and Bangladeshis who will need swimming lessons.

Personally, I don't trust the motivations of the prominent scientists who are pushing this agenda. I saw Rowland and Cicerone close enough when their issue was ozone depletion, and there was too much side-show wrestling for me to grasp the real magnitude of the problem and conclude that the Montreal Protocol was a proportionate solution. Arnold's long-standing "criticism" of the AGW proponents is that he'd like their help building robust, accurate economic models, which should be far easier than simulating the earth. I haven't seen much progress on that front, and it reduces my faith in such modeling.

aaron writes:

Don't know if there's much to it, but I've seen it suggested that the Ozone problem ended up not being as related to CFCs as thought. Most of the hole was natural variation, and the CFCs continued to be produced and released in many countries and also lots of similar substitutes, in increasing amounts, that cause the same effect, though not as large. (sorry, no cite. Perhaps someone else could do the leg work for me, I can't).

Also interesting to note is that the historical high res data points are a several hundred year large dots. The graphics we often see look a lot more precise than is meritted. We don't know how much temps and GHGs fluctuated in the past. We really don't know that GHG levels haven't spiked like this before. Or if they did during during cooling as well as warming on shorter time spans (though we do know that there has been cooling during periods of high GHG levels, areas where climate scientist should be focusing. To make break-through is science, you should really focus on the anomolies).

Not a fan of 1%. And the risks and uncertainty, I'm guessing, shown by most economic analysis put the change of big problems well below 1%. And 1% doesn't apply to natural randomness. 1% comes into play when there is human intent. I don't think Gaia is out to get us.

aaron writes:

Water really needs to studied more, and (I may be off-the-wall here) also the transition of states of other matter.

Thawing and evaporation absorb energy and tend to happen down low. Freezing and condensation release energy and happen up high. Are water cycles getting shorter/longer/same generally? And is more water moving more during these cycles? Is the amount of energy transport significant? I know this is probably well understood by climate scientists and probably isn't significant, but I'd really like to know about it.

I don't think there's been much attention paid to observation in the factors that are supposed to produce the positive feedbacks that could push GHGs temperature sensitivity beyond the 1.2C. Same for negetive feedback. Finding out why temps haven't run away in past is crucial to finding out whether they can now. And even with the feedbacks, the mainstream scientific consensus is the run-away warming and catastrophic effect are barely plausible.

Bruce G Charlton writes:

I follow the discussion of climate change with interest. The biggest problem is not what causes climate change but whether anything at all can be done about it.

Climate has always been changing throughout the history of the earth, and sometimes very quickly. It is important to try and understand why, and to try and predict this.

But whatever the causes, the really big question is whether human policy can influence the temperature of the earth. This is almost entirely separate from the question of causes.

Medicine is another science which deals with a complex system (the human body) and there are many diseases which are understood (for example in terms of genetic mutations, or physical changes) but which cannot be treated. ie. we know the cause but not the cure. (For that matter it is still very difficult to control the temperature of the human body using drugs!)

The problem with the current discussion of climate change is this matter of humans controlling the climate. To be candid, this strikes me as magical thinking.

There isn't even the tiniest scrap of evidence that human *policy* can control the planetary climate in any way at all - never mind the idea that humans can pick an ideal temperature and keep the world at this temperature.

Even if it turns-out that human-produced CO2 is indeed the main cause of climate change, then the fact that increasing CO2 warms the planet does not imply that reducing CO2 with cool it. With complex systems such as the earth or the human body, vast numbers of interventions can disrupt a system but reversing these interventions does not reverse the change or restore the prior state.

And yet the media is full of glib discussions of rival policy models to control CO2 using this or that mechanism, and describing how this will modify the climate to certain amounts.

People are discussing the 'best' way to do something that almost-certainly cannot be done at all (so far as we know).

My view: whatever the amount and cause of climate change, we should assume that humans can do nothing about climate change.

Therefore discussion of climate change should focus on prediction (and testing these predictions), and on how we will cope with climate change if and when it happens.

Daublin writes:

Mace, that is kind of you to try to respond. While you are nipping at corners of the argument, though, you are not taking it on for someone who really thinks about it. If CO2 causes positive feedback and runaway warming, then why did it not do so in the past? What we observe is (a) massive temperature changes unrelated to CO2, and (b) massive CO2 changes that do not presage rapid temperature changes. Both of these weaken the case that CO2 causes major warming.

This data makes a good litmus test for scientists versus advocates. Scientists look at this data and say it weakens the case for CO2 causing massive warming. Advocates look at it and talk around this. Both Al Gore and RealClimate fail this test. Go read MK's RealClimate link and try to find where they say this data weakens their case. Then ask yourself whether RealClimate is searching for the truth, or advocating. Likewise, try to find where Al Gore says that the ice core data weakens his case, but that he knows better evidence from somewhere else. To my knowledge, he has never said so. Is this a man concerned with the truth?

MK, you do not have to be a scientist to understand an evidence-based argument. That is the beauty of the scientific revolution. We no longer have to wait on a priest to tell us what the truth is.

MK writes:

Dear deniers!

Find all your answers here please: My Defense of Experts Against the Leading Expert

So either spread out into the graduate departments and do the science - or stop your hand-wavering. I am really bored of it.

So the GWC has a lot more work to do, perhaps in the PR department.

Perhaps true - but If I look at Bryan's book and if I look at what non-economists (of *either* party) think about Free Trade, Minimum Wage, Farm Subsidies or even Congestion Charges .. well I get the impression that economists have to do some work, too ... perhaps in the PR department ;)

Scientists can give a very rough probability of an event, but economists will tell you how much it will cost. From what I've read, the costs of acting—as defined by what environmentalists want— are still higher than doing nothing and dealing with the problems when they occur.
Economics is the study of the allocation of scarce resources. So, economists should be very interested in how we solve this problem or if it is even a big enough problem to solve. I am quite willing to concede AGW but still oppose the Kyoto treaty. The benefits have to exceed the costs.

I am 100% with you on these things - but that's, of course, NOT the line of the "deniers".

And if you want to gain a *econmic* perspective on it (costs-benefits, efficient solutions, .. ) then you HAVE to accept the science. It's that simple.

And that's what uber-skeptic Bjorn Lomborg finally did - did nobody recognise that he lauds the IPCC-reports nowadays?

dearieme writes:

As economists, you might care to enquire into the incentive structure that transformed some proponents of Global Warming from incompetents to crooks.

Barkley Rosser writes:

Hmmm. I think that Al Gore should not have focused so much on the Antarctic core data. It deals with long term effects, whereas what is going on now is way too short term. Not relevant. Regarding Evans and Spencer and the argument that the main nonlinear positive feedback effect involves water vapor, not according to the links in realclimate disparaged by many here. Try albedo.

Regarding reversing runaway temp changes, think volcanic eruptions, which come and go in cycles and bursts. One of the most prominent of the longer term skeptics, Reid Bryson, has been arguing for some time that the main forcer now is volcanic eruptions, which have been declining recently.

Another matter Evans and others reading this should be aware of is that many of the former skeptics have been changing their tune, including Patrick Michaels, and most recently Fred Singer, who is an adjunct at GMU, and who established the weather satellite system. He has long used its data for his arguments. He now accepts that global warming is happening, but questions the degree of anthropogenicity of the effect, and in effect says "it is inevitable" (hence, don't bother doing anything to/with the economy about it). For anyone who wants like Evans to point at satellite data, I think this is trumped pretty severely by the ground data of shrinking ice caps and glaciers, which is probably what has pushed such former skeptics as Michaels and Singer over, even as they question the degree of anthropogenecity.

More specifically regarding the August reading of CO2 and temperature, this is really silly. This is not such a localized effect, and furthermore, it depends on the angle of the sunlight hitting the earth. In the tropics it is coming down more directly, so more CO2 has less effect than at the poles, where the sunlight comes down at an angle. I remember over a decade ago being told by Pat Michaels that "to the extent there is a global warming effect [which he then questioned, but no more], it will be primarily at the poles at night." The steeper angle means even the lower amount of CO2 has a greater effect.

James A. Donald writes:

If you think the global warmers are going to have a rational response, you have not been reading climateaudit.com

Climateaudit.com audits research results, attempts to replicate research, etc. Most global warming research is obvious hype and fakery, and stuff that is not obvious hype and fakery indicates that global warming is considerably less than claimed.

JMG3Y writes:

A possible blog counter (given that the the primary sources that the original refers to are not identified):

Tropical tropospheric trends, 12/12/07 post on the blog RealClimate: "Climate science from climate scientists"

The Hadley Centre has a webpage that addresses these issues briefly, again appearing to refute - Climate change myths

Barkley Rosser writes:

Two clarifications:

Michaels only referred to the North Pole, not "the poles." Parts of Antarctica are cooling, as are some other parts of the world. Local effects vary considerably.

In connection with the latter, more important overall is not so much either the angle of the sun locally or the local concentration of CO2. It is how these interact with wind patterns, which distribute air around, obviously. This also undermines the hype about how local temperature and local CO2 concentrations do not correspond. Just not a big deal.

Let me note a nice global level generalization that former skeptic Pat Michaels (who hangs out at Cato) has been handing out for some time. Roughly speaking, CO2 concentrations are rising exponentially. OTOH, the direct impact of CO2 concentrations on global temperature is logarithmic (sorry about that Mr. Chemist, if this does not agree with what your "expertise" proclaims). For those of you who claim to be mathematicians like Evans, the combination of thise is roughly a linear rising trend. This is in fact roughly what has been happening globally to the average temperature, which projected forward puts us into the lower end of the range of IPCC projections.

James A. Donald,

Uh, are you denying that the Arctic ice cap has been shrinking to record low levels? Is this reported datum a lie?

Morgan writes:

I believe after reading this site for a while I can safely cross GMU off my list of serious economics schools. A mixture of arrogance and slavish devotion to theory is poor for any profession, but for economists it is especially bad. If they spent even a small percentage of their time actually trying to seek out the truth instead of trying to prove their paradigm to everyone they might turn out to be usefully productive. As it is now, granted only from this site, it certainly seems as if they are in the philosophic closet trying to overcompensate. Why do they spend so much time arguing over things they obviously don't know about trying to prove their paradigm instead of actually acting as if they really believe it.

Why don't they spend some time exploring the ramifications of libertarian economics? From this site, it seems painfully obvious that they aren't libertarian at all, despite their repeated assertions. I assert that they are libertarian about a very few things, which all oddly enough tend to be to the benefit of people in their position, but extremely anti-libertarian about things which would chip away at their subsidized advantages or of which they find inconvenient.

I don't mean to troll here. I'm just interested in libertarian economics and am finding this site increasingly irrelevant to serious intellectual inquiry.

TokyoTom writes:

David Evan's piece is an uninformed and lazy bit of skepticism, as others have pointed out here, and it discredits LvMI to have posted it.

Despite their strong arguments against government action on various policy issues, it is diappointing to see them squander their credibility by treading so carelessly into shallow and partial discussions of climate science. Rather than education, this seems more an attempt to pull the wool over their own eyes on the science, the better to collectively stand firm on a simple "we reject all government action" position. This will only hamstring their credibility in the policy debate.

More comments here: http://mises.com/blogs/tokyotom/archive/2007/12/14/who-knows-climate-science-the-mises-blog.aspx

David Evan's "breakout" prior post on the Mises blog and comments are here: http://blog.mises.org/archives/006581.asp

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