Quotes of the Day

As I report on climate change, I come across a lot of scary facts, like the possibility that thawing permafrost in Siberia could release gigatons of carbon dioxide into the atmosphere or the risk that Greenland could pass a tipping point and begin to melt rapidly. But one of the most frightening studies I've read recently had nothing to do with icebergs or mega-droughts. In a paper that came out Oct. 23 in Science, John Sterman — a professor at Massachusetts Institute of Technology's (MIT) Sloan School of Management — wrote about asking 212 MIT grad students to give a rough idea of how much governments need to reduce global greenhouse gas emissions by to eventually stop the increase in the concentration of carbon in the atmosphere. These students had training in science, technology, mathematics and economics at one of the best schools in the world — they are probably a lot smarter than you or me. Yet 84% of Sterman's subjects got the question wrong, greatly underestimating the degree to which greenhouse gas emissions need to fall. When the MIT kids can't figure out climate change, what are the odds that the broader public will?

The shocking study reflects the tremendous gap that exists regarding global warming. On the one hand are the scientists, who with few exceptions think climate change is very serious and needs to be dealt with immediately and ambitiously. On the other side is the public, which increasingly believes that climate change is real and worries about it, but which rarely ranks it as a high priority. A 2007 survey by the U.N. Development Programme found that 54% of Americans advocate taking a "wait and see" approach to climate-change action — holding off on the deep and rapid cuts in global warming that would immediately impact their lives. (And it's not just SUV-driving Americans who take this position — similar majorities were found in Russia, China and India.) As a result, we have our current dilemma: a steady drumbeat of scientific evidence of global warming's severity and comparatively little in the way of meaningful political action. "This gap exists," says Sterman. "The real question is why."

Hear Bryan Walsh and John Sterman talk about the problems faced by scientists in communicating the risks of climate change.

That's where Sterman's research comes in. "There is a profound and fundamental misconception about climate," he says. The problem is that most of us don't really understand how carbon accumulates in the atmosphere. Increasing global temperatures are driven by the increase in the concentration of carbon in the atmosphere. Before the industrial age, the concentration was about 280 parts per million (p.p.m.) of carbon in the atmosphere. After a few centuries of burning coal, oil and other fossil fuels, we've raised that concentration to 387 p.p.m., and it continues to rise by about 2 p.p.m. every year. Many scientists believe that we need to at least stabilize carbon concentrations at 450 p.p.m. to ensure that global temperatures don't increase more than about 2 degrees Celsius above the pre-industrial level. To do that, we need to reduce global carbon emissions (which hit about 10 billion tons last year) until they are equal to or less than the amount of carbon sequestered by the oceans and plant life (which removed about 4.8 billion tons of carbon last year). It's just like water in a bathtub — unless more water is draining out than flowing in from the tap, eventually the bathtub will overflow.

That means that carbon emissions would need to be cut drastically from current levels. Yet almost all of the subjects in Sterman's study failed to realize that, assuming instead that you could stabilize carbon concentration simply by capping carbon emissions at their current level. That's not the case — and in fact, pursuing such a plan for the future would virtually guarantee that global warming could spin out of control. It may seem to many like good common sense to wait until we see proof of the serious damage global warming is doing before we take action. But it's not — we can't "wait and see" on global warming because the climate has a momentum all its own, and if we wait for decades to finally act to reduce carbon emissions, it could well be too late. Yet this simply isn't understood. Someone as smart as Bill Gates doesn't seem to get it. "Fortunately climate change, although it's a huge challenge, it's a challenge that happens over a long period of time," he said at a forum in Beijing last year. "You know, we have time to work on it." But the truth is we don't.

If élite scientists could simply solve climate change on their own, public misunderstanding wouldn't be such a problem. But they can't. Reducing carbon emissions sharply will require all 6.5 billion (and growing) of us on the planet to hugely change the way we use energy and travel. We'll also need to change the way we vote, rewarding politicians willing to make the tough choices on climate. Instead of a new Manhattan Project — the metaphor often used for global warming — Sterman believes that what is needed is closer to a new civil rights movement, a large-scale campaign that dramatically changes the public's beliefs and behaviors. New groups like Al Gore's We Campaign are aiming for just such a social transformation, but "the reality is that this is even more difficult than civil rights," says Sterman. "Even that took a long time, and we don't have that kind of time with the climate."

The good news is that you don't need a Ph.D. in climatology to understand what needs to be done. If you can grasp the bathtub analogy, you can understand how to stop global warming. The burden is on scientists to better explain in clear English the dynamics of the climate system, and how to affect it. (Sterman says that the Intergovernmental Panel on Climate Change's landmark report last year was "completely inadequate" on this score.) As for the rest of us, we should try to remember that sometimes common sense isn't a match for science.

• Bryan Walsh