4. The World Melts and the Masses Mobilize
With an almighty crash, a mass of rock half the size of the Empire State Building dropped off the side of the Eiger Mountain in Switzerland last July 13. Thousands of tourists had flocked to see it fall, toasting its collapse with beer and cheers. Geologists had predicted the plunge for weeks, citing the retreat of an underlying glacier that had held the rock in place. Two days later, glaciologists at the University of Zurich reported that the area covered by alpine glaciers had shrunk by 50 percent in the past 150 years. They also predicted that if Earth's temperature rises by 5 degrees Fahrenheit, 80 percent of alpine glaciers will be gone by 2100. The loss is more than cosmetic: The Alps supply a crucial source of water for irrigating crops across Europe. "If they disappear," says study author Martin Hoelzle of the University of Zurich, "a lot of people will realize, oops, something is happening now, climate is changing really fast."
In 2006 signs of warming amassed so quickly that it was scarcely possible to keep track of them. A major study of Greenland showed that the landmass lost 100 billion metric tons of ice between 2003 and 2005, a melt rate three times faster than that seen five years ago and one that could be contributing to sea-level rise. A separate report indicated that the rate of global sea-level rise had accelerated during the 20th century; if it continues as predicted, by 2100 seas will lap shores 12 inches higher than they did in 1990.
"Should we be worried about this? By all means," says geoscientist Michael Oppenheimer of Princeton University. "Partly because you can't put the ice back once you lose it. The amount of warming that's already built in the system would bring Earth's temperature close to what it was when the sea level was 13 to 20 feet higher. If we don't act to cut emissions, there may not be time left to avoid this outcome. It may be that we're very close to the point where an irreversible and relatively rapid rise in sea level will occur that's enough to obliterate coastal civilization as we know it."
There is little doubt these changes are human induced, as the Bush administration-appointed federal Climate Change Science Program conceded in May. The panel reported that the world is warming throughout the lower atmosphere, as climate models had predicted, and acknowledged "clear evidence of human influences on the climate system." A study in February reported that heat-trapping greenhouse gases, such as carbon dioxide and methane, are being released at a rate 30 times faster than they were during a well-studied climate shift 55 million years ago that triggered an extreme period of warming. "It is as clear as a bell that the rapid warming of the past 30 years is due to increasing human-made greenhouse gases," says physicist James Hansen, director of NASA's Goddard Institute for Space Studies in New York and a leading authority on climate change.
Hansen has been warning about global warming since 1988, when he testified before Congress on the cause-and-effect relationship between atmospheric temperatures and greenhouse gas emissions. Nearly 20 years later, though, Hansen faces challenges in being heard: Last January, in The New York Times, he accused NASA of trying to censor his calls for reductions in heat-trapping gases. Since then, he says he's had no problems speaking out. "However, that does not mean that the [Bush] administration is paying attention to the implications of our research," he says. "Indeed, they seem almost oblivious to it."
Given the overwhelming evidence, a few big names sounded the battle cry. Most prominent was former Vice President Al Gore, whose documentary on climate change, An Inconvenient Truth, grossed $24 million. Another movie, The Great Warming, focused on evangelical Christian environmentalists, among them 86 church leaders who began urging Christians to fight global warming. Richard Branson, the owner of Virgin Atlantic airlines, pledged $3 billion to combat global warming by investing the money in the development of biofuels. And California governor Arnold Schwarzenegger has overseen legislation that will require the state to cut greenhouse gas emissions 25 percent by 2020.
Perhaps the most telling sign that global warming has gone mainstream came in October with the Weather Channel's launch of One Degree, a Web site whose mission is "to present an open, balanced dialogue around the scientific facts concerning global climate change." The site's name is drawn from the 1 degree Fahrenheit the world has warmed in the past 30 years; as the Web site states, "something so seemingly small as a single degree can change the world."