The science of global warming is weak, but the idea is strong.

Our Climate-Change Cathedral

By  Andrew Stuttaford

English: Alchemist

A 19th-century Scottish journalist, songwriter, and poet is not an obvious guide to a 21st-century intellectual and political phenomenon, but when it comes to making sense of climate-change zealotry, there are worse choices than Charles Mackay (1812–89), the author of Extraordinary Popular Delusions and the Madness of Crowds (1841), an acerbic, often drily amusing study of the frenzies — from witch mania to the tulip bubble — that regularly possess our supposedly sophisticated species.

“In reading the history of nations,” wrote Mackay, “we find that whole communities suddenly fix their minds upon one object, and go mad in its pursuit; that millions of people become simultaneously impressed with one delusion and run after it.” One recurrent fantasy, he jeered, was that the last trumpet is ready to sound: “An epidemic terror of the end of the world has several times spread.”

This is not — exactly — to categorize alarm over the impact of anthropogenic global warming (AGW) as just another of these prophecies of doom. The notion that a sharp, man-made increase in emissions of carbon dioxide and other greenhouse gases could have a significant effect on the climate is infinitely more soundly based than, say, the dodgy math of a Mayan apocalypse, but that — by itself — is not enough to explain why global warming has so evidently turned out to be the right fear at the right time. To learn more about that, The Age of Global Warming: A History, an intriguing new book (released in the U.K. in March) by the British writer Rupert Darwall (full disclosure: an old friend), is a good place to turn, but read some Mackay first.

To Darwall, “the science [of global warming] is weak, but the idea is strong.” He duly discusses some of the scientific controversies that have arisen, but the underlying objection to today’s scientific consensus on AGW set out in his book is more fundamental. Like Karl Popper, perhaps the last century’s most able philosopher of science, Darwall believes that the essence of a properly scientific theory is that it is falsifiable: “It should be capable of being tested against nature and therefore [potentially] refuted by evidence. . . . The more a theory states that certain things cannot happen, the stronger the theory is.” Put another way: What would it take to persuade believers in AGW or, more important, those concerned by what it could lead to, that they are mistaken? The answer is — let’s be polite — unclear.

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