A weekend is a long time in the history of hot air. On the day I started reading Bjorn Lomborg’s book, Al Gore and the UN’s Intergovernmental Panel on Climate Change (IPCC) shared the Nobel Peace prize. The next day, Jonathon Porritt, the chairman of the Sustainable Development Commission, laid into Gordon Brown for failing to match his “soaring speeches” on climate change with a Gore-like determination to act. The day after that, The Sunday Times reported that a right-wing pressure group intended to provide schools with free copies of The Great Global Warming Swindle, Channel 4’s notorious antiscience documentary.

And now here is Lomborg himself (the author of The Sceptical Environmentalist and, in the opinion of Time magazine, “one of the 100 most influential people in the world”), turning his sceptic’s eye on global warming. Like an indulgent schoolmaster he ruffles Gore’s hair (“It was obvious to me that [he] is sincerely worried about the world’s future”), but it’s pretty clear that if Lomborg had been on the Nobel jury the laurels would have rested on a different head. Lomborg is not just another antiwarming nutter. He acknowledges the reality of climate change and the part played in it by human activity. He just doesn’t think we should get so worked up about it. The message is pure Corporal Jones: “Don’t panic!

But there is a whiff of disingenuousness in his appropriation of the word “sceptical”. Does he want us to believe there is anything new in this? Scepticism is the very fire in science’s belly. It is why results and conclusions are peer-reviewed; why findings are not accepted until they have been replicated. Without scepticism there is no science, only opinion.

Lomborg’s view is that the cost of fighting climate change cannot be justified by the likely benefit, and that there are more pressing problems for the world to throw money at. He calculates, for example, that many more people die from winter cold than would perish in future from summer heat waves, and that climate change will, therefore, save more lives than it costs. He reckons that warming by 2050 will realise an annual-cost benefit of 1.4m lives, but omits the not insignificant detail that Europe’s 2003 summer heat wave slowed plant growth by a third and cut cereal crops by 36% (although he looks forward to a bonanza of fruit and veg). His calculator tells him that applying the Kyoto protocol would cost $23 for every tonne of CO2 saved, and would return only $2 worth of “good”. “Maybe,” he wonders, “we could have done more good for the world with those $23 elsewhere?”

A platoon of “top-level economists” helps him demonstrate that money would be better spent fighting disease and malnutrition, providing sanitation and clean water, and dismantling trade barriers. In Lomborg’s hierarchy of global challenges, climate change (described by Tony Blair as “the most pressing problem the world faces”) enters the list only at number 15. In support of this, he quotes a long list of countries that share his scale of values, “placing communicable diseases, clean drinking water and malnutrition at the top, with climate change at the bottom”. Well they would, wouldn’t they? In any perceived conflict between present and future, the present will always win – that is the nature of politics. It takes an economist to argue that one global crisis should be competitively costed against another and that the bottom line is bingo. Can you imagine any climate campaigner arguing that the cost of cutting carbon should be deducted from the Aids budget? Anyone unable to accept this intellectual machismo (the European Union, the IPCC, the overwhelming majority of climate scientists) is, as Lomborg recently expressed it, “pitiably weak on logic”.

The grand old man of environmental science, James Lovelock, gets it in the neck for his pessimism (“beyond the pale”), and for encouraging the likes of Gore to advocate “staggeringly bad policy judgments”. Albeit less entertainingly, Lomborg manoeuvres his sunbed into what might be called the Jeremy Clarkson position: “We ought at least to consider adaptive strategies as alternatives [to CO2 reduction] that would allow us to hold on to the positive effects of climate change while reducing or eliminating its damages.” If we really can’t stand the heat, then he looks forward to “increased access to air-conditioning”. How these powerful appliances can be run without further consumption of fossil fuel is another nice teaser for the technology boys.

“Fossil fuels,” Lomborg says, “give us low-cost light, heat, food, communication and travel.” Reducing such benefits, he argues, would be like imposing a 5kph limit to cut road deaths. Well, really? Is this barmy misrepresentation of the precautionary principle the best he can come up with? His copious acknowledgments include a tribute to one Ulrik Larsen for “improving many of my metaphors”. He should have gone the whole hog and employed Clarkson. At least then we would have had a laugh.

Lomborg makes a valuable contribution to the economics of good intention – we need to know we are not in for a cheap and easy ride. But he rests his case on a relatively modest rate of global warming (2.6C by 2100, against the 7C feared by some climatologists), and skates over the fact that the bleakest predictions come from the scientists with the longest CVs, who are neither idiots nor enemies of the free world. There remains only one answer to how much we should be prepared to pay to avert the risk of catastrophe: whatever it costs.

COOL IT: The Sceptical Environmentalist’s Guide to Global Warming by Bjorn Lomborg
Marshall Cavendish £19.99 pp352

Times Recommends

• The Sunday Times 100 best holiday reads
• What will we be reading this summer: the booksellers predict
• Literary festivals: a survivor’s guide