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.
