From Lord Lawson of Blaby.

Sir, It is understandable that Terry Barker, the director of the Cambridge Centre for Climate Change Mitigation Research (Letters, April 9) should disagree with my contention that mitigation is not a cost-effective policy – indeed, that it is positively harmful. But he should at least have read my book before asserting that I “ignored the Stern review's and IPCC report's conclusions on the costs of mitigation”. In fact I discuss these explicitly on pages 79-83 of my book, and the underlying issue of the discount rate in the notes on pages 125-7.