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Global warming: Greenland, West Antarctic ice sheets losing volume at record pace

Loss of ice volume doubles in just 5 years

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Arctic and Antarctic ice sheets are losing volume at a record pace. bberwyn photo.

By Bob Berwyn

FRISCO —Detailed new data from satellites and other sources show the world’s major ice sheets losing volume at a record pace, faster than at any time since satellite measurements started about 20 years ago.

Since 2009, the rate of volume loss from the Greenland Ice Sheet has doubled, and the rate of volume loss from the West Antarctic Ice Sheet has tripled, according to the new findings from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research. Continue reading

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Climate: Is the Greenland Ice Sheet near a tipping point?

How fast will the Greenland Ice Sheet melt? Map courtesy Change in Elevation over Greenland ICESat's precise elevation change measurements, combined with information from other technologies, are producing a comprehensive look at the behavior of Earth’s ice sheets -- critical for quantifying forecasts of sea level rise. Scientists used ICESat data to show changes in elevation over the Greenland ice sheet between 2003 and 2006. White regions indicate a slight thickening, while the blue shades indicate a thinning of the ice sheet. Gray indicates areas where no change in elevation was measured.  Credit: NASA Goddard's Scientific Visualization Studio

How fast will the Greenland Ice Sheet melt?
Credit: NASA Goddard’s Scientific Visualization Studio.

Detailed chemical analysis shows that southern portion of the ice sheet melted during historic warm phase

Staff Report

FRISCO —A period of global warming about 400,000 years ago may have pushed the Greenland Ice Sheet past a climate tipping point, resulting in widespread melting and raising sea level by more than 15 feet during a time when atmospheric temperatures were similar to current conditions.

The new study is one piece of a massive effort to understand how fast Greenland’s ice will melt as heat-trapping greenhouse gases force global temperatures upward. That melting will have huge implications for millions of people who live near coastlines, as well as for planners and policy makers trying to figure out how to prepare for the coming inundations. Continue reading

Climate: Study redefines Greenland Ice Sheet topography, finds greater risk of fast melting

How fast will the Greenland Ice Sheet melt? Map courtesy Change in Elevation over Greenland ICESat's precise elevation change measurements, combined with information from other technologies, are producing a comprehensive look at the behavior of Earth’s ice sheets -- critical for quantifying forecasts of sea level rise. Scientists used ICESat data to show changes in elevation over the Greenland ice sheet between 2003 and 2006. White regions indicate a slight thickening, while the blue shades indicate a thinning of the ice sheet. Gray indicates areas where no change in elevation was measured.  Credit: NASA Goddard's Scientific Visualization Studio

How fast will the Greenland Ice Sheet melt?
Credit: NASA Goddard’s Scientific Visualization Studio.

STAFF REPORT

FRISCO — New data on Greenland’s rugged shoreline topography doesn’t bode well for coastal cities around the world. A series of deep canyons stretching for miles under the Greenland Ice Sheet will enable warming ocean water to flow beneath the ice, accelerating melting and sea level rise, according to a new study published in the journal Nature Geoscience.

The bedrock canyons sit well below sea level, meaning that as subtropical Atlantic waters hit the fronts of hundreds of glaciers, those edges will erode much further than had been assumed and release far greater amounts of water, the study found. Continue reading

Wildfire ash a big factor in 2012 Greenland meltdown

In the images above, areas classified as “probable melt” (light pink) correspond to sites where at least one satellite detected surface melting. Areas classified as “melt” (dark pink) correspond to sites where two or three satellites detected melting.

Areas classified as “probable melt” (light pink) correspond to sites where at least one satellite detected surface melting. Areas classified as “melt” (dark pink) correspond to sites where two or three satellites detected melting.

Widespread surface melting become annual event by the end of this century

Staff Report

FRISCO — Widespread melting on the surface of the Greenland ice sheet was likely caused by a combination of warm temperatures and major depositions of soot and ash from wildfires in the western U.S. and Siberia. The ice sheet last saw a similar melting event in 1889, Dartmouth University scientists concluded in new research published this week in Nature.

“The widespread melting of the Greenland ice sheet required the combination of both of these effects — lowered snow albedo from ash and unusually warm temperatures — to push the ice sheet over the threshold,” said Kaitlin Keegan, the study’s lead author and a Dartmouth doctoral student. “With both the frequency of forest fires and warmer temperatures predicted to increase with climate change, widespread melt events are likely to happen much more frequently in the future.” Continue reading

Greenland’s ice sheet, past, present and future

A new study of the Greenland snowpack reached surprising conclusions about concentrations of carbon monoxide.

A new study of Greenland ice cores suggests parts of the ice sheet persisted through previous global warming spells.

Will there be a meltdown?

Staff Report

FRISCO — At least some parts of the Greenland ice sheet likely survived some of the warmest interludes in the Earth’s geologic climate history, researchers said last week as they announced findings of a study that discovered an ancient tundra landscape preserved under the Greenland Ice Sheet, below two miles of ice.

“We found organic soil that has been frozen to the bottom of the ice sheet for 2.7 million years,” said University of Vermont geologist and lead author Paul Bierman. The finding provides strong evidence that the Greenland Ice Sheet has persisted much longer than previously known, enduring through many past periods of global warming. Continue reading

Study: Record Greenland surface melt in 2012 didn’t speed up glacial movement

A new study of the Greenland snowpack reached surprising conclusions about concentrations of carbon monoxide.

A new study of the Greenland Ice Sheet may help refine sea-level rise forecasts.

‘Warmer summers will still lead to more rapid melting of the ice sheet …’

By Summit Voice

FRISCO — After examining a broad swath of the Greenland Ice Sheet, a science team led by University of Edinburgh researchers say they have a better understanding of how glacier movement is affected by melting ice in summer. That could lead to more accurate predictions of sea level rise.

The researchers gathered detailed GPS ice flow data and ice surface melt rates along a 115 kilometer transect in west Greenland and compared ice motion from an average melt year, 2009, with the exceptionally warm year of 2012.

The study, carried out in collaboration with the Universities of Sheffield, Aberdeen, Tasmania and Newcastle, was published in Proceedings of the National Academy of Sciences and supported by the Natural Environment Research Council.

“Although the record summer melt did not intensify ice motion, warmer summers will still lead to more rapid melting of the ice sheet,” said Professor Peter Nienow, of the University of Edinburgh’s School of GeoSciences, who led the study. “Furthermore, it is important that we continue to investigate how glaciers that end in the ocean are responding to climate change.” Continue reading

Climate: NASA takes close look at Greenland ice sheet

Surface measurements will provide baseline data for upcoming satellite mission

Click on the image for more information on Greenland's rapidly thinning ice cap.

Click on the image for more information on Greenland’s thinning ice cap.

By Summit Voice

FRISCO — A new airborne research effort by NASA will help measure ice loss in the Arctic by measuring changes in the height of the Greenland ice sheet and surrounding Arctic sea ice produced by a single season of summer melt.

The survey flights, running through Nov. 16, will collect data to improve the understanding of seasonal melt and provide baseline measurements for future satellite missions.

The land and sea ice data gathered during this campaign will give researchers a more comprehensive view of seasonal changes and provide context for measurements that will be gathered during NASA’s ICESat-2 mission, which is scheduled for launch in 2016. Continue reading

The Grand Canyon … of Greenland

Radar data deciphers topography beneath the ice

By Summit Voice

FRISCO — Someday, if the Greenland ice cap melts because of global warming, tourists may have a new destination to rival the Grand Canyon.

After studying data from NASA’s Operation IceBridge, geographers at the University of Bristol in the United Kingdom said they found evidence of 460-mile canyon hidden under a mile of Greenland ice. In places, the previously undiscovered canyon is 2,600 feet deep. The huge gash is thought to predate the ice sheet that has covered Greenland for the last few million years.

“One might assume that the landscape of the Earth has been fully explored and mapped,” said Jonathan Bamber, professor of physical geography at the University of Bristol in the United Kingdom, and lead author of the study. “Our research shows there’s still a lot left to discover.” Continue reading

Greenland ice shelt melting from beneath due to heat from Earth’s mantle

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The surface of Greenland’s ice sheet is growing darker, leading to more melting, but the ice is also melting from beneath because of heat rising from the Earth’s mantle. Image courtesy NASA Earth Observatory.

Study says basal melting should be factored into climate modelsBy Summit VoiceFRISCO — While all eyes have been on the surface of he Greenland ice sheet and its outlet glaciers in recent years, it turns out the ice is also melting at the bottom, heated by a high heat
flow from the mantle into the lithosphere (essentially the crust and the upper mantle). An international research team led by the GFZ German Research Centre for Geosciences concluded that the thinness of the Earth’s crust beneath Greenland enables an increase flow of heat from the mantle, but the effects on the Greenland ice sheet are highly variable. Continue reading

Record high temperature recorded in Greenland

Ice sheet surface melting above average in July

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A graph from the Greenland Today website shows 2013 surface melting in red to compare with average seasonal melting shown by the blue line.

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Daily maps from the Greenland Today website track surface melting.

By Summit Voice

FRISCO — A heatwave in Greenland culminated last week in the highest temperature recorded on the Arctic island since record-keeping started in 1958.

The official weather station at Maniitsoq/Sugar Loaf in southeastern Greenland reported a July 30 reading of 25.9 degrees Celsius (78.6 degrees Fahrenheit), breaking the old Greenland record of 25.5 degrees, set in 1990 in the same area of Greenland.

The Danish Meteorological Institute confirmed the record temperature in a press release. According to the weather experts, the regional heatwave resulted from a strong high pressure system over Greenland combined with a low pressure system over Baffin Island, leading to a flow of warm, dry air from the southeast.

The Danish meteorologists also said that reflected sunlight may also have been a factor in the reading, which has yet to be officially confirmed as the all-time high temperature record. Continue reading

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