Shrinking Glaciers Reveal Global Warming in U.S. Northwest (Jim Efstathiou Jr.)

Jim Efstathiou Jr.

Aug. 6 (Bloomberg) -- Three glaciers in different climate zones of the U.S. Northwest have shrunk rapidly since 1989, confirming the impact of global warming on their decline, the government said in a report.

The glaciers in Alaska and the state of Washington have shown a “rapid and sustained” loss of mass over the two decades, according to today’s report from the U.S. Geological Survey. The South Cascade glacier in Washington is shrinking at a rate that may see it disappear in 50 years, said Edward Josberger, the report’s lead author.

Glaciers in the Northwest have gained or lost mass from year to year since the agency began collecting data in 1957, because of changes in winter storm patterns tied to shifts in Pacific Ocean currents, Josberger said. The cumulative decline since 1989 suggests that global warming has overcome those seasonal variations.

“That’s telling us something on a larger scale is happening,” Josberger, a senior scientist at the geological survey stationed in Tacoma, Washington, said in an interview.