Acton Institute Powerblog

Global Warming Consensus Alert!

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Via Stephen Hayward at Planet Gore comes word of another scientist off the “consensus” reservation. According to David Evans (who, according to his bio, is a genuine rocket scientist – sweeeet…), “… in 1999 the evidence that carbon emissions caused global warming seemed pretty conclusive, but since then new evidence has weakened the case that carbon emissions are the main cause. I am now skeptical. As Lord Keynes famously said, ‘When the facts change, I change my mind. What do you do, sir?'”

Evans does a great job of laying out why the science on the issue of climate change is not settled, and also notes the potential dangers of the current “consensus”:

The evidence is not currently conclusive either for or against any particular cause of global warming. I think that it *is* possible that carbon emissions are the dominant cause of global warming, but in light of the weakening evidence I judge that probability to be about 20% rather than almost 90% as estimated by the IPCC.

I worry that politics could seriously distort the science. Suppose that carbon taxes are widely enacted, but that the rate of global warming increase starts to decline by 2015. The political system might be under pressure to repay the taxes, so it might in turn put a lot of pressure on scientists to provide justifications for the taxes. Or the political system might reject the taxes and blame science for misinforming it, which could be a terrible outcome for science because the political system is powerful and not constrained by truth.

Some people take strong rhetorical positions on global warming. But the cause of global warming is not just another political issue that is subject to endless debate and distortions. The cause of global warming is an issue that falls into the realm of science, because it is falsifiable. No amount of human posturing will affect what the cause is. The cause just physically is there, and after sufficient research and time we will know what it is.

Perhaps the best thing about this post is that it comes as part of a civil, rational debate about the merits of climate science, something that is sorely lacking in the current highly politicized climate. This sort of exchange is an encouraging sign that rationality may win out over hysteria in the end.

Marc Vander Maas


  • PatrickK

    No….in fact, David Evans is NOT a “rocket scientist”! He also is not a physicist, climatologist or anything else in the atmospheric sciences! He is a mathematician and also has a background in computing and electrical engineering……period! And this guy thinks he knows more than the thousands of scientists involved in researching global warming? I don’t think so!

  • Marc Vander Maas

    OK. So the fact that he worked for six years for the australian government on the very issue in question here counts for nothing? Cool. Here’s another list of names for you to chew on. They all signed on to a letter that states:

    In a public letter, we have recently advised the Canadian Prime Minister…that “global climate changes all the time due to natural causes and the human impact still remains impossible to distinguish from this natural ‘noise’ ”.

    We also noted that “observational evidence does not support today’s computer climate models, so there is little reason to trust model predictions of the future”.

    Of course, it’s likely that they’re all bought and paid for by the energy industry.

    Except this guy isn’t.

  • Jim Manzi

    You might find the follwoing National Review article on climate model uncertainty relevant to this discussion:

    Jim Manzi

  • Marc Vander Maas

    Great article, Jim. Well worth a read by all. I’ll be sure to note it in the next edition of Global Warming Consensus Watch.