Something has changed in the debate on man-made climate change: the US is engaged. But its engagement – or at least the engagement of President George W. Bush – is neither enthusiastic nor unconditional. In particular, at discussions among the heads of governments of the Group of Eight leading countries in Japan, Mr Bush stressed that China and India had to participate. In this, he was right: it will be impossible to tackle the problem without the participation of leading emerging countries. The question is on what terms they do so.

This is to ignore the debate on whether man-made climate change is either plausible or correctly assessed. I find the arguments sufficiently cogent to justify action. Above all, I find persuasive the argument of Professor Martin Weitzman of Harvard University that it is worth paying a great deal to eliminate the risk of catastrophe.* Those who reject such views need read no further.

The remainder of this column can be read here. Debate from our panel of economists appears below.

July 9, 2008 1:56am in Climate change | Comment