On Thin Ice
Sierra Nevada Glaciers Are Shrinking
Glaciers that have topped California’s Sierra Nevada Mountains for the past 1,000 years are shrinking markedly and even vanishing altogether, according to research by scientists from Portland State University and the U.S. Geological Survey. Seven Sierra Nevada glaciers that were surveyed over the summer are smaller than they were a century ago, including the Darwin Glacier near Bishop, Calif., which is about 50 to 100 feet thinner than it was in the early 1900s. Nathan Stephenson of the USGS was surprised to see notable changes in another glacier, the Goddard, just since 1976, the last time he photographed the area. “I thought, ‘Oh, my gosh. In my lifetime I’m seeing this change,'” Stephenson said. He declined to attribute all of the warming causing the glacial melt to human causes. “But maybe we are speeding it up now,” he said.