Glaciers in Southwest Alaska making rapid retreat

Feb 9, 2015

Pair of scientists studying glaciers in Ahklun Mountains say climate change causing glaciers to melt faster than ever before. 

Retreating glaciers in Ahklun Mountains, viewed from USFW flight.
Credit USFW

A new U.S. Fish and Wildlife report states that the glaciers in the Ahklun Mountains in Southwest Alaska are disappearing. Ten percent of the glaciers have completely melted away since they were originally mapped in the 1970s. As Matt Martin reports, scientists at the Togiak National Wildlife Refuge say these glaciers are the canary in the coal mine, so to speak, for larger glaciers around the world.

DILLINGHAM: Sitting in his office, U.S. Fish and Wildlife biologist Pat Walsh searches his computer for photos of the vanishing glaciers.

“I’ve got hundreds of photos of these glaciers.”

He points to one photo that shows a group of naked mountain peaks.

“A fragment of ice over here and fragment of ice over there.”

The photos show brown jagged rocks exposed to the sun where glaciers once covered the land.

“This is kind of an example of what’s happening all over the world.”

Walsh and his team used aerial photography and satellite imagery from the past five decades to measure the shrinking glaciers. They found a 45 percent overall decrease in glacial size during that time and that ten of the glaciers have completely disappeared.

Walsh says a changing climate is to blame, and at this pace the Ahklun Mountains may be completely glacier free by the end of the century.

“This change is happening so fast that we’re able to see these glaciers disappear in time that is really meaningful to people, rather than to think in geological time. So maybe we got to rethink the phrase, ‘Moving at a glacial pace’, because these seem to be moving faster than a glacial pace.”

Walsh says it’s unclear whether the melting glaciers will have any immediate impact on the region’s fish. He reports that as the glaciers melt the water temperatures will go up slightly and the amount of water being received is going to go down slightly.

“And those are both negative for fish. But sediment loads are going to decrease, so that is going to positive for fish. So there are both negatives and positives that are likely to occur.”

This isn’t the first time the glaciers in the Ahklun Mountains have melted away. 9000 years ago these same glaciers almost completely disappeared, only to come back to full strength.

But Professor Darrell Kaufman at Northern Arizona University, who co-wrote the report with Walsh, says this time is different. The glaciers aren’t shrinking because of natural changes, but because of man’s impact on the climate.

He says that absent human influences on the climate the glaciers would absolutely come back,

“They’d probably be advancing, in fact. There is considerable evidence from around the artic, including Alaska that prior to industrialization temperatures were lowering.”

The small size of the glaciers in the Ahklun Mountains in Southwest Alaska makes their melting easier to see. And that’s helpful for scientists like Walsh who believe this pattern will repeat elsewhere.

“They can provide, and they are providing, an example that people can use to predict what will happen in other places where there is more water tied up in these glaciers and there will be greater consequences.”

He says it’s a sign of greater changes to come.

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