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‘Benchmark’ glaciers shrinking faster

Study finds 3 Northwest glaciers shrinking faster

By: Les Blumenthal and Erika Bolstad
WASHINGTON — Climate change is shrinking three of the nation’s most studied glaciers at an accelerated rate, and government scientists say that finding bolsters global concerns about rising sea levels and the availability of fresh drinking water.

Known as "benchmark glaciers," the South Cascade Glacier in Washington state, the Wolverine Glacier on Alaska’s Kenai Peninsula and the Gulkana Glacier in interior Alaska all have shown a "rapid and sustained" retreat, according to a report by the U.S. Geological Survey that was released Thursday.

"They are living on the edge," Ed Josberger, a USGS scientist based in Tacoma, Wash., said of the three glaciers. "We’ve crossed a threshold, and these glaciers along with those globally are shrinking."

For years, scientists have reported that glaciers around the world are melting, but the study offers some of the most definitive evidence to date. Because the three glaciers are in different climates and elevations, they can be used to help understand thousands of other North American glaciers.

At the beginning of the 20th century, when glaciers were at their last peak in terms of size, the mass, or volume, of the remote South Cascade Glacier was estimated to be half a cubic kilometer, or about 654 million cubic yards. By 1958, it had shrunk to half that size. The latest measurement, in 2004, found that it had shrunk by half yet again.

"We are getting warmer, and glaciers are shrinking," Josberger said.

With some exceptions caused by unique or unusual local conditions — the glaciers on California’s Mount Shasta, for example — more than 99 percent of the country’s thousands of glaciers are shrinking, said Bruce Molnia, another USGS scientist.

USGS scientists have been taking measurements and detailed pictures of the three glaciers in the study since 1957, including using ice-penetrating radar to map the bedrock beneath them. The studies, begun as part of the International Geophysical Year, were part of a Cold War-era interest in polar science spurred by the threat of war with another polar nation, the Soviet Union.

The result is a half-century’s worth of data to use for modeling future changes, said Shad O’Neel, one of the USGS scientists based in Anchorage, Alaska, who worked on the study.

"These three glaciers have been losing mass since they’ve been studied, and that mass loss has gotten more rapid in the past 15 years," O’Neel said. "The most important thing about having a long record like this is that we can use these records to verify and validate models out into the future."

Although their data show a marked retreat in the sizes of the glaciers, changes to Alaska’s many glaciers are also visible to the naked eye, O’Neel said. Gulkana Glacier is "markedly different than it was in the late 1980s," he said.

Worldwide, most glaciers are losing mass, and some are disappearing. Glacier National Park’s namesake glaciers in Montana decreased from 150 to 26 over the past 99 years, and if current warming trends continue, scientists predict, they’ll disappear entirely by 2030. Scientists also have predicted that the famed snows of Africa’s Mount Kilimanjaro could retreat by 2015.

Scientists at the USGS’s Northern Rocky Mountain Science Center, who study the glaciers in Montana, point out that a drop in runoff means changes in water temperature for the creatures in the downstream ecosystem: insects, fish and the animals that eat them.

It also means less available drinking water, O’Neel said, pointing out that Anchorage’s drinking water is derived from runoff from Eklutna Glacier. There’s little threat to Anchorage’s water supply, but Bolivia’s Chacaltaya Glacier disappeared this year, earlier than predicted. Its disappearance worries scientists that other glaciers in the region could be melting faster than expected, potentially threatening water supplies for millions of people in South America.

The long-term study is "exactly the kind of science we need to invest in to measure and mitigate the dangerous impacts of climate change," Interior Secretary Ken Salazar said.

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Story Transcript

JESSE FREESTON, PRODUCER, TRNN: Welcome to The Real News Network. I’m Jesse Freeston, coming to you from our DC studios. And today I’m joined by Les Blumenthal of McClatchy’s DC bureau, McClatchy Newspapers. Les, welcome to The Real News.

LES BLUMENTHAL, MCCLATCHY NEWSPAPERS: Thank you.

FREESTON: So, Les, tell me about this article. You are reporting on the recession of glaciers in Washington state and Alaska. Could you tell us a little bit about what you found?

BLUMENTHAL: Well, there was a report released by the US Geological Survey, and it involved three glaciers which are called "benchmark glaciers". These are among the most studied glaciers in North America and—except for glaciers in Scandinavia and Switzerland that are among the most studied in the world. And they’ve had records and have been tracking these glaciers since 1957. And what they found is that these glaciers are significantly retreating because of global warming. And in the case of one glacier in the North Cascades in Washington state, since 1900 its mass has shrunk by 75 percent. And that’s an accelerating number—it’s growing and it’s growing. And the thing with this study is they’ve known for years that glaciers around the world are shrinking. Ninety-nine percent of the glaciers in the United States, of the thousands of glaciers in the United States, are thought to be growing smaller. But this was a very definitive study, with much more detailed measurements than in the past.

FREESTON: Well, it’s interesting, because many people have pointed to the winter of 2007-2008 in the north as being a time when glaciers were expanding. And one of these benchmark glaciers in Alaska.

BLUMENTHAL: The glaciers have grown occasionally in separate winters. Mostly when these great glaciers grow [it’s] because of snowfall, snow packing, those types of things. They contract, they eventually contract, because of melting, which is another sign of global warming warming. So in general the trend is smaller and smaller and smaller.

FREESTON: And so what are some of the local effects?

BLUMENTHAL: Well, the local effects, particularly in the Pacific Northwest, are less runoff from these glaciers. Snow-melt is a major part of supplying habitat and water for animals, fish, insects. It’s the whole bottom part of the food chain, if you will. There are also concerns about water supplies. Anchorage, for instance, is somewhat dependent on glaciers for water supplies. And there’s a study that’s been done about a glacier in Bolivia that is rapidly melting. And there are huge concerns in South Americas about how glacial melt in the Andes is going to result in people without drinking water, millions of people without drinking water.

FREESTON: Alright. Well, thanks a lot for your time, Les. And thank you for watching The Real News Network.

DISCLAIMER:

Please note that TRNN transcripts are typed from a recording of the program; The Real News Network cannot guarantee their complete accuracy.