Posted by: bmeverett | June 23, 2009

Climate Change – Here we go again

I hate to sound like a broken record, but the Great Climate Change Fallacy has reared its ugly head again. Alas, I have no choice but to keep responding.
A US interagency group called The US Global Change Research Program (USGCRP) issued last week a report to Congress entitled “Global Climate Change Impacts in the United States.” The New York Times story on this study was headlined “Government Study Warns of Climate Change Effects”. The first line in the Washington Post story was “Rising sea levels, sweltering temperatures, deeper droughts, and heavier downpours – global warming’s serious effects are already here and getting worse, the Obama administration warned on Tuesday in the grimmest, most urgent language on climate change ever to come out of any White House”

OK, let’s take a deep breath and go through this one more time. The Executive Summary of the report begins, “Observations show that warming of the climate is unequivocal. The global warming observed over the past 50 years is due primarily to human-induced emissions of heat-trapping gases. These emissions come mainly from the burning of fossil fuels (coal, oil, and gas), with important contributions from the clearing of forests, agricultural practices, and other activities. Warming over this century is projected to be considerably greater than over the last century”

This paragraph contains three, independent assertions. The first is that the climate has been changing and that we can see these changes. No big surprise here. THE CLIMATE IS ALWAYS CHANGING. The second assertion is that humans are causing the changes. The two propositions are unrelated. We know, for example, that the European climate was unusually warm from 800-1300, a period known as the Medieval Climate Optimum. We also know that Europe and North America were unusually cold from about 1600-1800, a period known as the Little Ice Age. We know these things from descriptions of people living at the time as well as records of agricultural output and other indicators. These climate changes were caused by some combination of solar activity, ocean currents, volcanism, cosmic rays, changes in the Earth’s orientation and orbit and perhaps other variables. We simply don’t know. It does seem unlikely, however, that these climate patterns were caused by human industrial activity, which was minimal at the time. Let’s say it one more time: the fact that the climate is changing is not evidence of human causation. Those asserting man-made climate change can’t make their case by pointing to receding glaciers or increased droughts or rainfall. They must demonstrate that they can isolate human factors, such as the burning of fossil fuels, from the other variables affecting climate. If you don’t understand the impact of all the variables, you don’t understand the impact of any of the variables.

The third and final assertion is that the future will be worse than the past. This argument is based on computer models which reflect our knowledge about how climate changes. That knowledge is insufficient to explain past climate variability, and it’s insufficient to predict future variability. We should not be swayed by computer models, which don’t know anything more than we do. They just do the arithmetic faster. I can predict that the Red Sox will win the World Series in 2025, and I may be right. Building a computer model that makes that prediction is meaningless, unless I can demonstrate that the model can predict other things that actually happen. Our General Circulation Climate Models have been unable to predict anything. They couldn’t predict the temperature rises of the 1990s, and they couldn’t predict the cooling that has occurred over the last several years. They were unable to predict the substantial ice loss in the Arctic a few years ago nor could they predict the rate at which it would recover. Models that predict “increased variability” are useless. Science works on falsifiable hypotheses: we predict that x will happen and we measure whether it does or doesn’t. Climate modelers often claim that unusually heavy rainfall validates their models, while claiming that unusual droughts are equally supportive.

Our climate change debate could use a little less hype and a little more science. What bothers me more than anything is that my tax dollars pay for this nonsense.



  1. So your point of view is that since models are still primitive and inaccurate we should do nothing, i.e. we should ignore the potential dangers of man-made climate change.
    I am a PhD with experience in atmospheric sciences and my point of view is that since there are irrefutable indicators that man-made activity is responsible for increasing levels of CO2 in the atmosphere for the past 100 years, and that since CO2 can produce greenhouse effects which I can measure and test in the lab, there is at least a “risk” (not a proof) that burning fossil fuels may generate man-made climate changes. And that as a responsible human being, not just a scientist, I would rather be behave conservatively until my models can become more reliable and prove or disprove global warming. This is just common sense. Your position is selfish and irresponsible; you are basically saying that if you are proven wrong in the future, you are willing to let your grandchildren suffer the consequences.

    • Thanks for this comment, but I respectfully disagree. Let’s say you’re right that there is a significant chance of severe climate impacts from the burning of fossil fuels. The reality is still that (1) the bill passed by the House will be either effective or low cost, but not both, (2) the US is not a big enough CO2 emitter to deal with the problem by ourselves and (3) no other country in the world is doing anything substantive other than talk. The worst possible outcome (and the one the current Administration seems to favor) is to impose serious costs on the US economy with no tangible benefit. In what sense is that approach responsible?

  2. This is but the first step that will allow us to go to the world and demand action, something we did not have the moral authority to do before. The measures being taken today will take years to impact our economy in any serious way, and in the meantime, they will also give us the economic munition(through import tax threats) to move the world to also behave responsibly. If we fail, or if global warming is proven to be a hoax, we can always change the laws. To use your words: It is time to do something substantive, not just talk.

    • This is terribly naive. China and India are intent on moving 2.5 billion people out of poverty, and they are riding a wave of coal to do so. “Green energy” isn’t going to do it. The Europeans are talking a good game but are not even going to meet their Kyoto targets.

      The fact that the US is willing to damage our economy to make a symbolic statement of intent will have no impact on anyone else. China will undoubtedly be very happy about this situation while it increases its competitive and strategic advantages over us. Whatever the scientific argument, the US will be better off with a vibrant growing economy.

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