Wenchuan earthquake. A deeply scarred land.

LONGMENSHAN, CHINA—In the morning of 12 May 2008, Ren Diandong gave a talk on landslide modeling at the Institute of Atmospheric Physics of the Chinese Academy of Sciences (CAS) in Beijing. A few hours later, Ren’s model was put to the supreme test: a magnitude-7.9 earthquake in Sichuan Province’s Longmenshan range (Science, 20 June 2008, p. 1578). As early reports came in that afternoon of a disaster that would leave nearly 90,000 people dead or missing, Ren, a climatologist at the University of Texas, Austin, knew the quake had struck in landslide country—and with the rainy season about to begin, the fractured land would soon be thick with mudslides. In the weeks that followed, Ren and colleagues pored over satellite images of landslides, rock falls, and debris flows in an earthquake-ravaged area the size of Belgium. Their model suggests that slides buried about 235 million tons of carbon in vegetation from Longmenshan’s forest ecosystem. As it rots in the coming decades, it should release more than 100 million tons of carbon dioxide (CO2), according to the model—roughly equivalent to 2% of current annual global emissions from fossil fuel combustion. Soil in many landslide zones will also be nitrogenpoor for decades to come. As China mourns the first anniversary of the Wenchuan earthquake, the ecological toll is just coming to light. Besides unleashing greenhouse gases, landslides caused widespread habitat fragmentation—threatening the region’s unique assemblage of species, including its dwindling wild population of giant pandas. Landslides destroyed 122,000 hectares of vegetation, including 98,000 hectares of forest, says Bao Weikai, a plant ecologist at Maoxian Mountain Ecosystem Research Station of CAS’s Chengdu Institute of Biology (CIB). It will take years of survey work, he and others say, to understand how Sichuan’s biodiversity hot spot will respond.