What We Know About Climate Change by Kerry Emanuel. The MIT Press, $14.95, 85 pages.


The Cleveland Plain Dealer

November 25, 2007

Scientist Kerry Emanuel gives us the global warming facts, plain and simple

By PHILLIP MANNING

Does the world really need another book about global warming?

Surprisingly enough, the answer is yes. Kerry Emanuel’s new book, “What We Know About Climate Change,” is one of the best and is certainly the shortest. In less time than it takes to eat dinner, the respected atmospheric scientist and MIT professor filters out the noise and presents clearly the essence of the issues surrounding global warming.

Most Americans now accept that the Earth is growing hotter, but fewer than one-third believe it is caused by human activities. This doubt stems from the public’s perception that scientists disagree about the cause. This book aims to set the record straight: Global warming is happening; it is caused by humans; it is a virtual certainty to continue for a long time; and scientists are close to unanimous in agreeing with these conclusions.

Two earlier books - Elizabeth Kolbert’s “Field Notes from a Catastrophe” and Tim Flannery’s “The Weather Makers - did an outstanding job of describing what global warming is doing to the planet. Unlike those books, Emanuel offers no anecdotes about polar bears stranded by disappearing Arctic ice or speculations on the collapse of fragile ecosystems. Instead, he digs into the science of global warming.

Emanuel explains, simply and lucidly, how greenhouse gases - such as carbon dioxide and water vapor - absorb heat and prevent it from radiating away from Earth. He then considers two facts. Fact 1: Careful measurements show that the amount of carbon dioxide in the atmosphere increased dramatically in the last century as humans burnt fossil fuels. Fact 2: In that same period, the temperature of the Earth also increased.

The question is, did Fact 1 cause Fact 2 or did they merely occur simultaneously? Could the increase in Earth’s temperature in the last century be caused by natural variations in climate?

Emmanuel comes up with a novel way to answer that question. He compares the results of several computer climate models - with and without human-generated emissions of carbon dioxide and other substances. He finds that it is impossible to account for the Earth’s warming over the last 30 years without the human element. He winds up stating that “almost all climate scientists” now believe that global warming is due primarily to human activities.

This conclusion seems indisputable to Emanuel. And he suspects that those who remain unconvinced have been misled. He summarizes the
situation neatly: This “soap opera is kept alive by a dwindling number of deniers constantly tapped for interviews by journalists who pretend to look for balance.”

Emanuel offers few solutions, and sees slight chance for a rational discussion of what to do. “As long as we continue to elect scientific illiterates like Senator James Inhofe,” he writes, “who believes global warming to be a hoax, we will lack the ability to engage in intelligent debate.”
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