Nigel Lawson on global warming...

He's a former British chancellor of the Exchequer, speaking in New Zealand...

AS it is, the temperature projections (the Intergovernmental Panel on Climate Change) does come up with in its fourth and latest report range from a rise in the global average temperature by the year 2100 of 1.8C for its lowest emissions scenario to one of 4C for its highest emissions scenario, with a mean increase of slightly under 3C. The average annual temperature in Helsinki is less than 5C. That in Singapore is in excess of 27C, a difference of more than 22C. If man can cope with that, it is not immediately apparent why he should not be able to adapt to a change of 3C when he is given 100 years in which to do so.

Let us look at the gloomiest of the IPCC's economic development scenarios, according to which living standards ... would rise, in the absence of global warming, by 1 per cent a year in the developed world and by 2.3 per cent a year in the developing world. It can readily be calculated - using, to repeat, a cost of global warming (based on the gloomiest IPCC warning) of 3 per cent of GDP in the developed world and as much as 10 per cent in the developing world - that the disaster facing the planet is that our great-grandchildren in the developed world would, in 100 years, be only 2.6 times as well off as we are today, instead of 2.7 times; and that their contemporaries in the developing world would be only 8.5 times as well off as people in the developing world are today, instead of 9.5 times as well off. And this, remember, is the IPCC's very worst case.

The major cause of ill-health, and the deaths it brings, in the developing world is poverty. Faster economic growth means less poverty but - according to the man-made CO2 warming theory, incorporated in the IPCC's scenarios - a warmer world. Warmer but richer is in fact healthier than colder but poorer.

The more one examines the current global warming orthodoxy, the more it resembles a Da Vinci code of environmentalism. It is a great story and a phenomenal bestseller. It contains a grain of truth and a mountain of nonsense. And that nonsense could be very damaging indeed.

We appear to have entered a new age of unreason, which threatens to be as economically harmful as it is profoundly disquieting.