Bjorn Lomborg is a Danish statistician and darling of those who believe that markets should not be regulated and that concerns about the environment are overblown. He is articulate, certain in his opinions and well informed on the statistical minutiae of the topics he investigates. Indeed, so compelling and entertaining are the grains of truth that adorn his latest book, Cool It, that you are certain to hear them soon in dinner table conversation. But is this book, as its subtitle proclaims, really an acceptable "guide to global warming"?

In his opening paragraph Lomborg establishes a revealing dichotomy: "In the face of . . . unmitigated despair" about global warming, he intends to write a book that is optimistic about humanity's prospects. It's seductive rhetoric. But is climate change really about unmitigated despair? And can Lomborg's optimistic solutions actually work? It all depends on how well he's read the science.

Cool It commences with a look at polar bears. Despite what you might have heard, they're doing fine, according to Lomborg. If we want to protect them better, we should forget about melting ice and just ban hunting. For every bear the Kyoto Protocol saves, a hunting ban would save 800 bears, he conjectures. Lomborg then moves on to the consequences of the warming itself. He does not doubt that it is occurring, nor that it is caused by humans, but almost alone among commentators he finds reason to welcome it. In Europe, 200,000 people die from excess heat each year while 1.5 million die from cold, he asserts. His message is simple: more warming, less death. In this and many other projections, Lomborg is astonishingly certain about how things will be in the future. In a sentence italicized for emphasis, he writes that in 2200 -- nearly 200 years from now -- more people will still die from cold than from heat.

Glib, misleading associations mark Lomborg's style. In his chapter on glaciers, he states that since "we're leaving the Little Ice Age" (which, in fact, we left long ago) it's not surprising that glaciers are dwindling. Remarkably, he believes that is more good news, because "with glacial melting, rivers actually increase their water contents, especially in the summer, providing more water to many of the poorest people in the world." "It boils down to a stark choice," he lectures us. "Would we rather have more water available or less?"

Lomborg's flawed grasp of climate science is most evident when he discusses sea levels. He makes much of the 2007 Intergovernmental Panel on Climate Change's (IPCC) projection that sea level will rise by "about a foot," misleadingly noting that this is lower than previous projections. He does not tell us that the IPCC figures do not account for collapsing ice sheets, which may result in far larger rises, due to the difficulty of predicting how glacial ice will react to warming. While Lomborg waves vaguely in the direction of ice melt and collapse, he assures us it's not a problem. We'll just put up dikes. Indeed, with dikes, he asserts, some nations might end up with more land than they have today. And so the arguments go on, from rising seas to extreme weather events to malaria and other tropical diseases, the collapse of the Gulf Stream, food shortages and water shortages. In one case after another, Lomborg asserts, it's cheaper and better to do nothing immediately to combat climate change, but instead to invest in other things.

The deepest flaw in Cool It is its failure to take into account the full range of future climate possibilities. The computer models project outcomes ranging from mild, which he acknowledges, to truly catastrophic, which he ignores. While the chances of catastrophic climate change may still be small, they are increasing: By comparing real world data with the 2001 IPCC projections, researchers have shown that the sea is rising more swiftly than even the worst case scenarios in the projections.

Lomborg's mantra is the supposedly high costs of dealing with climate change. The Stern Review on the Economics of Climate Change is a detailed analysis of those costs, commissioned by the UK Treasury and reported to the prime minister. Stern, a senior government economist, argues that it's much cheaper to combat climate change than to live with the consequences. Because Stern and Lomborg cover the same ground but strongly disagree, I had hoped for a detailed critique of the report, but Lomborg devotes a scant three and a half pages to it (about the same space he devotes to an analysis of the far less relevant social activist George Monbiot). Lomborg asserts that "a raft of academic papers have now come out all strongly criticizing Stern, characterizing his report as a 'political document' and liberally using words such as 'substandard,' 'preposterous,' 'incompetent,' 'deeply flawed,' and 'neither balanced nor credible.' " Such broad accusations are impossible to assess. He further asserts that the Stern report was not peer reviewed (making one wonder whether Cool It or the Internet postings he cites criticizing Stern were), and that it's slanted toward "scary" scenarios. This latter assertion is simply not true. Stern gives a straight reading of the range of possible climate outcomes.

Despite all the supposed benefits global warming will bring, Lomborg acknowledges that some people want to act to reduce it. His solution is to abandon the Kyoto process and devote more dollars to research on technologies to prevent it. Yet we already have the necessary clean technologies: What we need is market penetration for them, and this will only come by getting the polluter to pay, which means adopting a carbon tax much higher than the $14 per ton of carbon dioxide released into the atmosphere that Lomborg is willing to allow.

What, ultimately, is Cool It all about? On the surface, it's a cry from a compassionate conservative not to waste money on combating climate change when that money could be better spent helping the poor. But why climate change rather than military spending? By empathizing with those who are concerned about climate change and poverty, and trying to persuade them to divert their energies, Cool It is a stealth attack on humanity's future.

Copyright 2007, The Washington Post. All Rights Reserved. --This text refers to an out of print or unavailable edition of this title.