Thursday, April 03, 2008

As I suspected...

Climate challenge underestimated? : Nature News

This looks like a really important story on the economics of climate change. My suspicion has long been that the optimistic talk of countries being able to achieve huge changes in CO2 emissions with lots of "green" technologies and without too much economic pain was bunkum, and this report indicates my hunch may be right:

Climate policy expert Roger Pielke Jr, climatologist Tom Wigley, and economist Christopher Green lay out in a commentary article published in Nature 1 today why they think that the emission scenarios the IPCC produced nearly a decade ago, which are still widely used, are overly optimistic. They note that most of the IPCC’s 'business as usual' emission scenarios assume a certain amount of 'spontaneous' technological change. The size of this assumed change is unrealistic, they argue, and deceives policy-makers and the public about the crucial role policy must have in encouraging the development of technologies to prevent dangerous climate change.

Such a large chunk of the needed energy-efficiency improvements is built in to these 'business as usual' scenarios that the degree of change requiring special effort seems artificially small, they argue. According to the authors' own calculations, IPCC scenarios make it seem as if the technical challenge of stabilizing greenhouse-gas emissions at around 500 parts per million — a concentration which scientists think will prevent average global temperatures from rising more than 2 °C — is a quarter of its true size.

Richard Tol, an energy and environmental economist at the Economic and Social Research Institute in Dublin, Ireland, also says that the IPCC has underestimated the cost of technology, and notes that the cost of mitigating against climate change increases as time goes on. If Pielke and colleagues are correct, the cost of controlling global warming could go up by a factor of 16, argues Tol.
I trust Professor Garnaut is reading this with interest.

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