The guest blogger is Tom Kenworthy, Senior Fellow at the Center for American Progress. The U.S. Geological Survey images below show the retreat of South Cascade Glacier, Wash.
For a half century the U.S. Geological Survey (USGS) has been closely studying changes in glaciers in three different climatic regions in Alaska and Washington state. In a new report, the Interior Department agency details “recent dramatic shrinkage” in the Wolverine and Gulkana glaciers in Alaska and the South Cascade glacier in Washington state’s Cascade Mountains.
“Since 1989,” USGS reports, “the cumulative net balances of all three glaciers show trends of rapid and sustained mass loss.”
USGS scientist Edward Josberger said the changes observed in the three U.S. glaciers are consistent with other shrinking glacers around the world as they respond to climate change. “There is no doubt that most mountain glaciers are shrinking worldwide in response to a warming climate,” Josberger said.
A USGS video of photographs taken over time offers dramatic evidence of the recent rapid shrinkage of the South Cascade Glacier.
The accelerating pace of global warming is forcing scientists to revise their estimates of when some of the world’s iconic and most important glaciers will totally disappear.
National Geographic News reported in March, for example, that a USGS ecologist working in Montana’s Glacier National Park has concluded that the park’s namesake glaciers will disappear by 2020, ten years ahead of what had previously been the consensus prediction.
In June a new study of ice loss in Greenland demonstrated that the ice sheet was melting faster than earlier predicted and was responsible for nearly 25 percent of global sea rise in the last 13 years. Such rapid melting was not predicted by IPCC models.
Also in June, it was reported that Switzerland’s glaciers have shrunk by 12 percent in just the past decade, the worst ten-year loss in 150 years.
Rapid shrinking of glaciers doesn’t just affect the scenery. It will bring economic dislocation and political instability to some of the world’s most volatile regions.
A critically important Himalayan glacier that provides 90 percent of Pakistan’s agricultural irrigation water is now predicted to disappear by 2035. And hundreds of millions of people in India, China and Nepal could face water shortages because of other melting glaciers in the Himalayas, according to a World Wildlife Federation report.