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Surface melt on Greenland ice cap speeds glaciers

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Meltwater pools on the surface of the Sermeq Avannarleq Glacier, in a region about 10 miles from the ice sheet margin in Southwest Greenland. Photo courtesy William Colgan/CIRES.

Findings suggest sea level calculations may need to be adjusted

By Summit Voice

*Adapted from a NASA press release

FRISCO — Scientists are keeping close watch on the behavior of the Greenland ice sheet as they try and calculate how fast the ice will melt as the planet continues to warm. The stakes are high — acceleration of the meltdown will start to raise sea levels around the world at an increasing pace, so the speed-up of glaciers flowing into the sea have garnered plenty of attention.

And new satellite measurements suggest that some of Greenland’s giant glaciers are also moving up to 1.5 faster then they were just 10 years ago, possibly lubricated by surface meltwater draining through cracks and warming the ice from the inside.

“Through satellite observations, we determined that an inland region of the Sermeq Avannarleq Glacier, 40 to 60 miles from the coast, is flowing about 1.5 times faster than it was about a decade ago,” said Thomas Phillips, lead author of the new paper and a research associate at the time of the study with the Cooperative Institute for Research in Environmental Sciences at the University of Colorado, Boulder. Continue reading

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Global warming: What about the heat-island effect?

New number-crunching confirms rising global temps

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April 2013 temperature anomalies compared to the 1951 to 1980 average.

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The escalator of global warming.

By Summit Voice

FRISCO — For years, anti-science global-warming deniers have claimed the instrumental temperature record that shows steady warming is skewed because of the so-called heat -island effect in urban areas. The instrumental temperature record shows warming of about 1.2 degrees Celsius since 1952.

The well-established global temperature record comes from thousands of readings, many from stations that are untainted by human development, and scientists account for the heat island effect when they average overall global temperatures.

And now a new study, using historical weather observations that don’t include  temperature recordings from land stations has confirmed global land warming, according to a scientist at NOAA’s Cooperative Institute for Research in Environmental Sciences. The finding refutes concerns that artifacts in land-based observing systems have led to an artificial global land warming trend.  Continue reading

Alaska’s Columbia Glacier may stop retreating by 2020

New modeling may help generate more accurate predictions of sea level rise

An iceberg from Alaska’s Columbia Glacier floats in Prince William Sound. Photo by Kim Fenske.

By Summit Voice

SUMMIT COUNTY — Alaska’s Columbia Glacier — a poster child for the impacts of global warming — is likely to stop receding around 2020, when the terminus of the glacier retreats into water shallow enough to provide a stable position through 2100 by slowing the rate of iceberg production.

The Columbia Glacier is a large (425 square miles), multi-branched glacier in south-central Alaska that flows mostly south out of the Chugach Mountains to its tidewater terminus in Prince William Sound.

The new study by Boulder-based University of Colorado scientists with the Cooperative Institute for Research in Environmental Sciences shows that a single glacier’s contribution to sea level rise can “turn on” and “turn off” quite rapidly, over a couple of years, with the precise timing of the life cycle being difficult to forecast. Continue reading

Global warming: Colorado researchers pinpoint atmospheric greenhouse gas levels with six-year sampling project

Valuable program threatened by NOAA funding cuts

A NASA map shows global temperature anomalies in March 2012.

By Summit Voice

SUMMIT COUNTY — An intensive long-term monitoring program has enabled researchers to analyze and compare emissions from man-made fossil fuels and trace gases in the atmosphere, which could help measure the effectiveness of efforts to reduce greenhouse gases — but the program is being threatened by budget cuts.

“We think the approach offered by this study can increase the accuracy of emissions detection and verification for fossil fuel combustion and a host of other man-made gases,” said CU-Boulder Senior Research Associate Scott Lehman, who led the study with CU-Boulder Research Associate John Miller.

Lehman, with the Institute of Arctic and Alpine Research, said the approach of using carbon-14 has been supported by the National Academy of Sciences and could be an invaluable tool for monitoring greenhouse gases by federal agencies like NOAA. Continue reading

Melt-water creates positive feedback loop in icecap thaw

Water on the surface of glaciers and ice sheets can trickle down through cracks and transport heat to deep inside, speeding melting. PHOTO COURTESY UNIVERSITY OF COLORADO.

CU research shows how water can warm glaciers and icecaps from within

By Summit Voice

SUMMIT COUNTY — New research shows that water flowing through ice sheets like Greenland‘s can spread heat throughout the ice and speed up melting tremendously, according to the  University of Colorado at Boulder.

“We are finding that once such water flow is initiated through a new section of ice sheet, it can warm rather significantly and quickly, sometimes in just 10 years, ” said lead author Thomas Phillips, a research scientist with Cooperative Institute for Research in Environmental Sciences. CIRES is a joint institute between CU-Boulder and the National Oceanic and Atmospheric Administration.

Existing models of ice sheets haven’t accounted for the heat that’s spread internally — they only factored in surface heat from the sun’s radiation and warmer air on the surface of the ice, the researchers said. Based on the study, the Greeland ice sheet could respond to such warming on the order of decades rather than the centuries projected by conventional thermal models. Continue reading

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