Glacial truths

7/22/2012

Few things in nature are as dramatic as the sight of a large chunk of glacier splitting off and sliding into the sea. Calving, as it is called, used to be a rare occurrence. Not anymore.

Last week, a mass of ice measuring roughly 46 square miles broke away from the Petermann glacier on Greenland's northwest coast. This follows a similar break-off in 2010, when the glacier lost an area of 97 square miles.

A professor of ocean science told the Washington Post that the glacier's end point is now at "a location where it has not been for at least 150 years." Glaciers aren't supposed to change with such speed.

Scientists say that ice calving of this magnitude should take 10 or 20 years. What is occurring is contrary to ice-flow behavior observed over centuries.

Scientists attribute most of the ice loss on the Petermann glacier to melting deep underwater. But air temperatures around Greenland have risen by 4.5 degrees Fahrenheit in the past 25 years -- a rate five times that of the rest of the world.

Researchers want to study what is happening, including whether climate change is behind the breakup. Because the issue of greenhouse gases and global warming is so politicized, scientific pronouncements are more measured than they've been. Yet researchers can't be cowed; they must go where the evidence leads.

The United States is undergoing its worst drought since the 1950s. This has been the warmest decade since the 1880s. Let Congress debate whether global warming, and human contributions, are real. Others will watch the glaciers.