A London Spectator article by the British writer Rupert Darwall on the failings of Britain’s Met Office (the UK’s official weather forecaster) produced this somewhat angry response in the UK edition of the Huffington Post from Bob Ward of the LSE’s Grantham Research Institute on Climate Change and the Environment. Darwall in turn replied here (kudos to the Huffington Post for letting both men have their say). Readers can judge for themselves who has the upper hand.
The wider point contained in Darwall’s reply (which is also a key element in The Age of Global Warming, his new intellectual and political history of the climate change issue, a book of which my review, much like AGW itself, is running a little behind schedule) is, however, also well worth reproducing here:
Amidst all the agitprop, there is a nugget of science: no 15-year period of global temperature [the recent ‘pause’ in global warming] yields a statistically significant trend. But then, to its embarrassment, neither could the Met Office demonstrate a statistically significant trend in global temperature for the last 130 years. That doesn’t mean observed temperatures did not rise – they did – or that global warming, whether man-made or not, did not happen. Rather it illustrates the sheer difficulty in demonstrating whether the rise is outside a range of random natural variation and of moving from the physics of the test tube to the immense complexity of the atmosphere.
Bert Bolin, the first chairman of the IPCC, acknowledged that global warming was not something ‘which you can prove.’ In one of his last lectures, the late Stephen Schneider – one of the most intellectually able of all climate scientists – asked his students whether the science of anthropogenic climate change was settled. Dumb question, he answered. ‘Climate science is not like test tube science,’ Schneider said. ‘You don’t falsify.’
Although codified by Popper in the 1920s, falsifiability was the standard set in the Scientific Revolution and used with devastating effect by Lavoisier in his demolition of the phlogiston theory of combustion. Instead of seeking evidence that would falsify, climate science follows a much older injunction, one from the Beatitudes: ‘Seek and ye shall find.’
As Popper argued, evidence can be found for virtually any proposition, so when global temperatures don’t rise as anticipated, evidence is sought in ocean temperatures, sea ice extent and glacier retreat. The absence of a falsifiability test renders the science of global warming inherently weak. Instead acceptance of the central proposition of global warming – that the earth’s atmosphere is rapidly warming thanks to man’s activities – marks a reversion to pre-scientific standards, principally its reliance on consensus, peer review and appeals to authority….
I have no doubt that some of those who ‘deny’ (to use that loaded verb) anthropogenic global warming do so on grounds with very little scientific merit (this is not, for example, a debate that ought to have too much room for Noah) , but that does not get around the central fact that there is a flaw—the absence of falsifiability—right at the heart of the AGW thesis, a flaw made inevitable, not by any sinister conspiracy, but by the immense complexity of the climate system. That does not mean that man is not having an effect on the climate, but it does mean that we should be careful before claiming to know exactly what those effects are, and, therefore, even more careful about deciding what to do about them.