Monday, 16 July 2007

The great global warming non-swindle

Folks have been queuing up to try and discredit a new study that shows that changes in solar output are not responsible for recent increases in global temperature. According to Mike Lockwood, one of the authors, the study was initiated partly in response to the documentary 'The Great Global Warming Swindle', directed by Martin Durkin. There's a lot to say about this documentary, which is described in the media as 'controversial' and by most climate scientists as 'bollocks', but luckily Wikipedia contains a useful summary of the debate surrounding it. Mike Lockwood himself is reported as saying 'All the graphs they showed stopped in about 1980, and I knew why, because things diverged after that...You can't just ignore bits of data that you don't like'.

Durkin himself responded to the study in the Grauniad, claiming that global temperatures peaked in 1998, and so rising CO2 levels cannot be responsible for climate change. This is an absolutely basic error (repeated by various commentators, e.g. Christopher Booker in the Telegraph), working on the assumption that if global warming is real, then every year must be warmer than the previous one. As residents of the UK will be well aware, there's this thing called 'weather'. As a result, there will inevitably be variations around a warming trend. As ever, some years will be warmer and some cooler, but the overall trend will be upward. Durkin also talks about temperatures falling during the post-war economic boom, when CO2 levels increased dramatically. Most scientists have explained this as a result of higher particulate levels at that time, before there was much legislation to reduce air pollution. So all of this is bollocks, and known to be bollocks. But perhaps the dead give away that Durkin is full of shit is that his response is published in the letters pages of the Guardian, and not as a refereed comment in the Proceedings of the Royal Society A, where the original study appeared. Mike Lockwood has now suggested that Durkin do exactly that, which ought to be entertaining if Durkin takes up the offer.

What really grates for me is the assumption amongst climate change critics that scientists are engaged in some kind of groupthink, ignoring data so they can keep the grant money rolling in. Scientists in general do not uncritically accept anything, as anyone who has presented at a conference or sent a paper to be reviewed will know. The IPCC reports are the most rigorously assessed and peer-reviewed reports in any field. It's worth remembering that letters to the Guardian are not peer-reviewed at all.

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