Wheel of Global Fortune

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Since 1999, Prinn, Jacoby, and their collaborators have published many scientific papers based on the model's predictions. And to get the word out to the public and to lawmakers, they made a pair of gambling wheels to represent the probabilities of a range of temperature increases over the next hundred years. Like upright versions of the wheel used on Wheel of Fortune, each is a spinning pie chart. One wheel assumes no policy change, and the other assumes that the Kyoto Protocol--which calls for reducing emissions of carbon dioxide and five other greenhouse gases--is implemented by 2010 by all the countries that originally agreed to it. It also assumes adoption of more aggressive policies that lower global greenhouse-gas emissions to less than double their preindustrial levels by 2100. (See "Which Wheel Would You Rather Spin?" opposite.)

In public speeches, Prinn demonstrates the two wheels and asks how much the audience, given $100,000 to gamble, would pay for an energy policy that let them spin the one with the more favorable outcomes. The answer, he says, tends to be around $10,000. The cash is entirely hypothetical, of course, but Prinn says his informal surveys reveal that the public is willing to invest money in the short term in order to lower the risk of disastrous climate change. And the investment required could turn out to be surprisingly small. According to a British study completed last year, implementing policies that mitigate climate change would cost just 1 percent of the global gross domestic product.

"People are used to dealing with uncertainty," says Prinn. "They are used to thinking about changing their habits and paying for something even when they know the outcome they want is not guaranteed." For example, a patient informed of a heart-attack risk 50 percent above average is unlikely to refuse to pay for cholesterol medication just because a particular life expectancy can't be promised.

Right now, says Prinn, "the computers are purring away, working full time to do a new set of calculations" that incorporate new findings about, among other things, the oceans' ability to absorb heat. The oceans slow down warming, "but not as much as we thought," he says. "It would have been wonderful if the science had concluded it's not such a bad situation, but that's the nature of our research. We let the results fall where they may." The MIT scientists are now redoing the wheels to depict a more urgent situation.

Prinn is convinced that the United States can't wait any longer to mitigate climate change, and he harbors only cautious optimism that it will act quickly enough. "I have a wait-and-hope-and-see attitude about what [policy changes] might happen to address this issue," he says. "Energy security is looming [larger and larger]. These are issues liberals and conservatives are concerned about." Within academia, "the students are driving change," he says. "Young people are not climate skeptics."