The Science of Global Warming
November 23, 2010 Methodology

I have not liked to post anything on global warming outside of the economic implications. In this case, I think it is simply worth raising the observation that the modelers who do climate projections and the modelers who do macroeconomic projects know little more than jack squat. Regular readers understand the macro problems – to think that we can take an economy of hundreds of millions of different people and tens of millions of different firms, with millions of things changing from minute to minute such as tastes, availability of substitutes, tax rates, weather, and so on, and then think that we can write down a 100 equation model with 100 unknowns (or more) or even a 4 equation model with 4 unknowns, and think that not only explains past macroeconomic activity, but that can also be used to predict future macroeconomic activity is a fool’s errand. Actually, it’s worse than that. It’s a fool’s journey around the entire universe. But for some reason we in the economics profession remain enamored with the modeling and prediction of the macroeconomy. Plus, we only have about 100 years of data with which to estimate these models. How many of you would even base your decision on what cold medicine to take after having the experience of only 100 people to rely on for evidence?

The deal with the climate modeling is far worse. I don’t know the first damn thing about global warming outside of the fact that it has gotten warmer and that humans have tossed a helluva lot of CO2 into the air. Beyond that, I am not sure the scientists know much more. Here is the latest summary of what we know and don’t from Richard Lindzen:

Here are two statements that are completely agreed on by the IPCC. It is crucial to be aware of their implications.

1. A doubling of CO2, by itself, contributes only about 1C to greenhouse warming. All models project more warming, because, within models, there are positive feedbacks from water vapor and clouds, and these feedbacks are considered by the IPCC to be uncertain.

2. If one assumes all warming over the past century is due to anthropogenic greenhouse forcing, then the derived sensitivity of the climate to a doubling of CO2is less than 1C. The higher sensitivity of existing models is made consistent with observed warming by invoking unknown additional negative forcings from aerosols and solar variability as arbitrary adjustments.

Given the above, the notion that alarming warming is ‘settled science’ should be offensive to any sentient individual, though to be sure, the above is hardly emphasized by the IPCC. 4

And of course, coming right on the heels of this is the following proclamation about the results of the 5th IPCC report, research on which has yet to commence:

News from the United Nations:

Robert Orr, UN under secretary general for planning, said the next Intergovernmental Panel on
Climate Change report on global warming will be much worse than the last one.

Hmm, that kind of confirms what critics have been saying for years, that the IPCC has nothing to do with science.  Because, you see, to my knowledge the scientists of the next IPCC have not even started their work, but the UN leadership has already determined what the report will say.  Which is consistent with their process in the last go around, where the UN political guys crafted the management summary first, and then circulated it to the scientific teams with instructions to adjust their sections of the report to fit the pre-existing conclusion.

All of this courtesy of the must-read daily Coyote who also recently reminded us that Al Gore has taken off his clothes.

"3" Comments
  1. Could one win the Nobel Prize in Economics for proving economic modeling is better than climate modeling, or vice versa? Which is the story about man bites dog?

    I have spent much time when real money has been on the line, and have never taken the advice of any analyst without great skepticism. Before personal computers you actually often got better economic and investment research, and with Milton Friedman you got good advice about the problems with money and prices.

    Regarding the question of whether global warming has been significantly affected by the consumption of hydrocarbons to fuel US prosperity, I have read much and remain a show-me skeptic. It makes no sense to me how an increase, even if it could be measured convincingly, of, say, 40 parts per million of CO2, would be worth bothering about. It does not pass what we in the consulting company I worked for called the logic test. Uri Geller bending forks falls into the same category: OK, assume he can do it, so what? It is not the same as if he could wave his hands, furrow his brow, and make cold fusion happen.

    I am willing to buy the idea about the climate getting warmer, at least around here, but I wonder about whether our knowledge is reliable even about that, and whether it is valid to extend that imprecise incomplete knowledge into a prediction about the future.

    The big problem is the Least Signifigant Integer problem, which Wintercow understands, but I am going to try to explain for the benefit of other readers who may have not taken a physics or chem lab.

    Whatever data you use, it must all be rounded off to the degree of precision of your roughest number. Thus, if your data is precise to a tenth, plus or minus a tenth, then all your data has to be rounded to that degree of precision. That means that even if your calculator gives you a result of 1.00987934, you have to round it off to 1.1, if any of your other data is at least that precise.

    Now Michael Mann of Penn State, a chief scientific source for the IPCC, uses tree rings to measure fluctuations in global temperature. Others have used ice cores in Greenland, and surely others have used measurements at university observatories at Harvard, Oxford, and the U of R. A hundred years ago, are there any observations that have been used in the modelers’ numbers that are less precise than plus or minus one degree?

    Well, then, how far back can you go for precise enough data, and where does that data come from? There is probably a lot of data from Lowell Observatory, but how about Liberal, Kansas, or the Ecuadorian Amazon jungle? How about Wild Deer, Texas, or halfway between San Diego and Pago Pango, and was that on the surface of the ocean or at two thousand feet above?

    These questions are relevant because we sort of think the Earth has warmed maybe six tenths of one degree since a hundred years ago, and if we can reduce carbon dioxide by .005 percent, it is worth destroying capitalism and putting our futures in the hands of stupid foreign diplomats.

    They do not care anything about any of this. What they want is money, and if it means being compensated for an alleged bad anchovy harvest, well, that works.

  2. I have read what Richard Lindzen has written in the Journal, have seen several interviews on television. (He is a prof at MIT.)

    What is frustrating is that the movers and shakers like Henry Waxman completely ignore anything, preferring to increase everybody’s heating bills, gas costs, etc., willy-nilly. Professor Lindzen is invisible, even though I remember him saying that ice cores are at best accurate to ten years, and I bet he was talking about Greenland weather. He is one guy I would pay to have dinner with.

    The more fundamental question is explaining the variations in the weather in Rochester since you moved from Pittsfield, MA.

  3. From 2001 through October, 2010 the atmospheric CO2 increased by 21.8% of the total increase from 1800 to 2001 while the average global temperature has not increased significantly and the trend of the average of the five reporting agencies from 2001 through 2009 is actually down. The 21.8% CO2 increase is the significant measurement, not the comparatively brief time period.

    The factors that resulted in the 20th century global temperature run-up have been discovered. The contribution of atmospheric carbon dioxide is between small and insignificant. The time-integral of sunspot numbers and effective sea surface temperature are the main contributors.

    A simple equation, with inputs of accepted measurements, calculates the average global temperatures since 1895 with 88% accuracy (87.6% if CO2 is assumed to have no influence). See the equation, an eye-opening graph of the results and how they are derived in the pdfs at (see especially the pdfs made public on 4/10/10 and 6/27/10).

    The future average global temperature trend that this equation calculates is down.

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