Global warming: Study helps quantify how much Alaska’s melting glaciers contribute to sea level rise

Posted on May 24, 2013 by Bob Berwyn

Research aims to fine-tune sea-level rise projections

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The Columbia Glacier in Alaska is one of the most rapidly changing glaciers in the world. Visit this NASA Earth Observatory web page for more information.

By Summit Voice

SUMMIT COUNTY — As part of a global study of melting glaciers and rising sea level, two University of Alaska Fairbanks geophysicists helped compile a global inventory of glaciers, with a focus on Alaska.

Before the study, only about 40 percent of Alaska’s glaciers were inventoried. The two researchers, Anthony Arendt and Regine Hock, concluded that Alaska remains one of the top contributors to global sea level. (more…)

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Global warming: Mt. Everest’s glaciers melting away

Posted on May 15, 2013 by Bob Berwyn

Temperatures up, precipitation down in key Asian watersheds

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A new study finds a decline in snow and ice on Mount Everest (second peak from left) and the national park surrounding it. Photo courtesy Pavel Novak.

FRISCO — Even at the frozen roof of the world in the mighty Himalaya, global warming is evident.

The snow line in the Mt. Everest region has moved uphill by 180 meters (590 feet). Glaciers in the region are shrinking, some by as much as 13 percent in the past 50 years, and precipitation has declined, according to a team of scientists who will present their findings this week at the Meeting of the Americas in Cancún, Mexico.

Glaciers smaller than one square kilometer are disappearing the fastest and have experienced a 43 percent decrease in surface area since the 1960s, according to Sudeep Thakuri, who is leading the research as part of his PhD graduate studies at the University of Milan in Italy. Based on the detailed measurements of satellite images, the pace of melting speeding up, Thakuri said. (more…)

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Climate: Heat-trapping CO2 also makes ice more brittle

Posted on October 11, 2012 by Bob Berwyn

New MIT research suggests carbon dioxide has direct impact on glaciers and ice caps

Cracks in the ice on Dillon Reservoir, Dec. 25, 2012. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — Have you ever poured a can of warm coke into a glass full of ice cubes and listened to the cubes crack?

Something similar might be going on in the atmosphere, as MIT researchers have shown that direct exposure to carbon dioxide makes ice caps and glaciers more susceptible to cracking.

The study is the first to show this kind of a direct impact from increasing atmospheric CO2, which as a heat-trapping greenhouse gas is directly responsible for much of the increase in global temperatures during recent decades. (more…)

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Global warming: How fast will the ice melt?

Posted on September 14, 2012 by Bob Berwyn

Research finds that ice sheets can be very sensitive to short-term temperature variations. Photo by Bob Berwyn.

Study shows some glaciers and ice fields can respond quickly and dramatically even to short-lived climate changes

By Summit Voice

SUMMIT COUNTY — It’s pretty clear that glaciers and ice fields have been melting the past few decades under relentless global warming. But scientists aren’t sure exactly how fast the melting will proceed, whether it will speed up, or perhaps stabilize at some point.

A new study looking back at historic changes in response to climate variations may help answer some of those questions. The research shows that glaciers on Canada’s Baffin Island expanded rapidly during a brief cold snap about 8,200 years ago, suggesting that changes can be sudden and drastic.

“One of the questions scientists have been asking is how long it takes for these huge chunks of ice to respond to a global climate phenomenon,” said study co-author Jason Briner, PhD, a University at Buffalo associate professor of geology. “People don’t know whether glaciers can respond quickly enough to matter to our grandchildren, and we’re trying to answer this from a geological perspective, by looking at Earth’s history.” (more…)

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Climate: Greenland’s glaciers going, going … not so fast!

Posted on May 5, 2012 by Bob Berwyn

These icebergs recently calved from the front of the north branch of Jakobshavn Isbrae, a large outlet glacier that drains 6.5 percent of the Greenland ice sheet. The fact that they are upright, indicated by their dirty and crevassed surfaces, suggests they calved from the floating end of a glacier. PHOTO COURTESY IAN JOUGHIN/UNIVERSITY OF WASHINGTON.

Rate of change pinpointed with extensive satellite data; new estimates suggest slower impact to sea level

By Summit Voice

SUMMIT COUNTY — Greenland’s glaciers have sped up by about 30 percent in the past 10 years, a significant change, but not as much as estimated in other previous climate-change scenarios.

The documentation from 200 outlet glaciers suggests that Greenland’s contribution to rising sea level in the 21st century might be significantly less than the upper limits some scientists thought possible.

Reporting in the May 4 issue of Science, the scientists said they saw no clear indication  the glaciers will stop gaining speed during the rest of the century. By 2100 they could reach or exceed the scenario in which they contribute four inches to sea level rise. (more…)

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Global warming: New study says Himalayan glaciers not melting as fast as previously predicted, at least for now

Posted on April 20, 2012 by Bob Berwyn

Some glaciers have expanded in the past decade, but concerns remain about growing glacial lakes in the region

Retreating mountain glaciers in Bhutan. This satellite image shows the termini of several glaciers in the Himalayan mountains of Bhutan. The glaciers have been receding over the past few decades, and lakes have formed on the surfaces and near the termini of many of the glaciers. IMAGE COURTESY NASA.

By Summit Voice

SUMMIT COUNTY — Glaciers in the Himalaya are not shrinking as fast as once predicted by the Intergovernmental Panel on Climate Change.

Some glaciers in the Karakoram Range have grown slightly in the past decade, according to a team of European researchers who recently completed one of the most detailed surveys of the region to-date.

But there are still valid concerns about variability that could leave some valleys dry, at least on a seasonal basis.

“The majority of the Himalayan glaciers are shrinking, but much less rapidly than predicted earlier,” said Tobias Bolch, of the University of Zurich and Dresden University of Technology. (more…)

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Climate: Loss of glaciers linked to diminished biodiversity

Posted on March 19, 2012 by Bob Berwyn

New study outlines unexpected global warming impacts in tropical regions

This NASA image shows the termini of the glaciers in the Bhutan Himalayas. Glacial lakes have been rapidly forming on the surface of the debris-covered glaciers in this region during the last few decades.

By Summit Voice

SUMMIT COUNTY — The rapid melting of glaciers from the northern Rockies and other parts of the world won’t just impact tourism in places like Glacier National Park — it’s also likely to have a profound effect on regional ecosystems, resulting in significant loss of biodiversity in glacier-fed streams.

As glaciers vanish due to global warming, so will those species dependent upon the icy runoff from melting ice, according to a study recently published in the journal Nature Change.

“The knowledge is new and startling. Glacial runoff is cold, nutrient-poor and physically unstable, and therefore, typically species-poor,”  said Dean Jacobsen of the Freshwater Biology Section at the University of Copenhagen’s Department of Biology. “Traditionally, we have not attached great significance to these ecosystems within the context of local or regional biodiversity,” Jacobsen said. (more…)

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Global warming: Glacial runoff waning in Andes

Posted on December 21, 2011 by Bob Berwyn

Alpamayo, in Peru's Cordillera Blanca.

Not much time left to adapt to reduced runoff, scientists warn

By Summit Voice

SUMMIT COUNTY — South American glaciers that provide critical drinking water are retreating faster than expected, and meltwater discharge is also decreasing.

This means that the millions of people in the region who depend on the water for electricity, agriculture and drinking water could soon face serious problems because of reduced water supplies, according to a team of researchers who have closely monitoring the glaciers in the northern Andes. (more…)

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Global warming: New study pinpoints glacier impacts

Posted on January 11, 2011 by Bob Berwyn

The majestic Aletsch Glacier, the largest in the European Alps, will probably lose about about 50 percent of its volume in the next few decades. PHOTO FROM THE WIKIMEDIA COMMONS.

Smaller glaciers will melt faster and fuel sea level rise

By Summit Voice

SUMMIT COUNTY — A new study by Canadian researchers suggests that smaller glaciers in mountain regions will be especially hard-hit by global warming, with many of them likely to shrink by 50 percent from their current ice volumes.

The melt-off from those glaciers will contribute to about 12 centimeters of sea-level rise by 2100, according to the University of British Columbia research published this week in Nature Geoscience.

“There is a lot of focus on the large ice sheets but very few global scale studies quantifying how much melt to expect from these smaller glaciers that make up about 40 percent of the entire sea-level rise that we observe right now,” said Valentina Radic, a postdoctoral researcher with the university’s department of earth and ocean sciences and lead author of the study. (more…)

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Environment: Alaskan glaciers not melting as fast as thought

Posted on March 4, 2010 by Bob Berwyn

NAU geographer Erik Schiefer surveys a debris-covered glacier margin. Photo by Amanda Stan. Click on the image for a larger view.

Loss in last 40 years was over-estimated, but rate of melting has doubled in last two decades

By Bob Berwyn

SUMMIT COUNTY — Alaskan glaciers may not be melting quite as fast as previously thought, but the pace at which it’s melting has doubled in the last 20 years, a team of scientists reported this week.

Researchers from Northern Arizona University, the University of British Columbia, the University of Northern British Columbia Université de Toulouse studied 75 percent of Alaskan glaciers intensively, comparing optical data from satellites with topographic maps dating back to the 1950s.

They concluded that glacier melt in Alaska between 1962 and 2006 contributed about one-third less to sea-level rise than previously estimated.

Northern Arizona University publicized the results of the research in a press release this week, and a paper on the project was published in the February issue of Nature Geoscience.

Click here to see an photo essay of melting Alaska glaciers published by NPR.

Previous studies overestimated the rate of melting because of thick deposits of rock debris that offer protection from solar radiation and, thus, melting. They also did not account for the thinner ice along the edges of glaciers that resulted in less ice melt.

(more…)

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