Matt Ridley writes My life as a climate lukewarmer- The polarisation of the climate debate has gone too far in his blog, The Rational Optimist.
I was not always a lukewarmer. When I first started writing about the threat of global warming more than 26 years ago, as science editor ofThe Economist, I thought it was a genuinely dangerous threat. Like, for instance, Margaret Thatcher, I accepted the predictions being made at the time that we would see warming of a third or a half a degree (Centigrade) a decade, perhaps more, and that this would have devastating consequences.
Gradually, however, I changed my mind. The failure of the atmosphere to warm anywhere near as rapidly as predicted was a big reason: there has been less than half a degree of global warming in four decades — and it has slowed down, not speeded up. Increases in malaria, refugees, heatwaves, storms, droughts and floods have not materialised to anything like the predicted extent, if at all. Sea level has risen but at a very slow rate — about a foot per century.
Also, I soon realised that all the mathematical models predicting rapid warming assume big amplifying feedbacks in the atmosphere, mainly from water vapour; carbon dioxide is merely the primer, responsible for about a third of the predicted warming. When this penny dropped, so did my confidence in predictions of future alarm: the amplifiers are highly uncertain.
Another thing that gave me pause was that I went back and looked at the history of past predictions of ecological apocalypse from my youth – population explosion, oil exhaustion, elephant extinction, rainforest loss, acid rain, the ozone layer, desertification, nuclear winter, the running out of resources, pandemics, falling sperm counts, cancerous pesticide pollution and so forth. There was a consistent pattern of exaggeration, followed by damp squibs: in not a single case was the problem as bad as had been widely predicted by leading scientists. That does not make every new prediction of apocalypse necessarily wrong, of course, but it should encourage scepticism.