Alaska's Mountain Glaciers are Changing Faster Than Scientists Thought

Sep 18, 2014

A DHC-3 Otter aircraft flown for NASA Operation IceBridge-Alaska surveys flies over Bering Glacier, Alaska with a scanning laser that measures how much ice has been lost since previous overflights. Based on these measurements, Bering Glacier is shrinking at a rate typical of Alaska glaciers and alone is losing over 3 cubic kilometers of ice to the oceans annually.
Credit Chris Larsen/University of Alaska-Fairbanks

Fairbanks, AK - Alaska’s glaciers are shrinking faster than scientists had thought, but glaciers that terminate in the ocean may be relatively resilient to climate change in comparison to their land-locked counterparts.  The data comes from a multi-year airborne survey conducted by NASA.

Every Spring and every Fall, Operation Icebridge – Alaska flies surveys over Alaska’s glaciers to look at how the change over time. “There really is no question that glaciers in Alaska are losing mass and contributing a lot to sea level," says Evan Burgess. He is a scientist with the Glaciers Group at the University of Alaska, Fairbanks’ Geophysical Institute. “The big question for us is exactly how much sea level rise we’re going to be dealing with," he says.

Burgess took part in a teleconference with scientists from NASA this week to discuss the agency’s various airborne field campaigns. He says the only way to predict sea level rise accurately is to find out how glaciers respond to temperature, changes in precipitation and to look at the change in the rate of iceberg production.

“All of these things are very tricky to figure out in Alaska because Alaska is massive, the glaciers are very complex, they cover an area the size of South Carolina and each of these glaciers are responding to climate change in a different way,” says Burgess.

A small airplane is outfitted with a LIDAR altimeter, or scanning laser. It flies over glaciers to measure their surface elevation. Burgess says, over time, the data tells scientists how fast Alaska’s glaciers are changing.

“For the few glaciers that terminate in the ocean, most of their potential for catastrophic iceberg mass loss is kind of already run its course and what that’s done is it has changed those glaciers in a way that’s making them relatively resilient to climate change right now,” Burgess explains.

But the vast majority of glaciers in Alaska do not terminate in the ocean. Burgess says mass loss among Alaska’s mountain glaciers, like those in the Wrangell St. Elias is controlled entirely by changes in climate.

“For these glaciers, we’re seeing a very different pattern," he says.  "All of the glaciers are shrinking without exception and collectively they’re shrinking faster than we previously thought and this is so much so, that they’re actually offsetting the relatively small amount of mass loss that we’re seeing from glaciers calving into the ocean.”

Earlier this year, the disintegration of the West Antarctic ice sheet made headlines in part because the long-term effect is a rise in sea level.  But Burgess says it’s unlikely that Alaska’s glaciers will have the same effect.

"Glaciers in Alaska are actually more closely tied and more sensitive to climate then we previously thought and what this means in the case of controlling Alaska’s contribution to sea level is it really is in our own hands.”

The project was originally started by researchers at UAF back in 1994.  For the last six years, funding has come from NASA’s Operation Icebridge program. Funding continues at least through next year.