Glaciers Not On Simple, Upward Trend Of Melting

Two of Greenland’s largest glaciers shrank dramatically and dumped twice as much ice into the sea during a period of less than a year between 2004 and 2005. And then, less than two years later, they returned to near their previous rates of discharge.

The variability over such a short time underlines the problem in assuming that glacial melting and sea level rise will necessarily occur at a steady upward trajectory, according to lead author Ian Howat.

They also found the pace toward the sea was faster at the front edge of the glaciers than farther up the mountain. For example Kangerdlugssuaq’s front edge increased in speed by 80 percent in 2005 while 19 miles inland the speed increased 20 percent. This caused the glaciers to thin, stretch and weigh less overall, which also slowed them down.

“All this in a matter of a few short years for these two glaciers is not the way glaciologists are used to thinking,” Howat says. “We’re used to thinking of the ice sheets in terms of millennia or centuries.”

Science Daily