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Is the Greenland Ice Sheet slip-sliding away?

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.

New study probes role of subglacial runoff channels

Staff Report

FRISCO — Scientists continue to probe and poke at the Greenland Ice Sheet to try and figure out exactly how fast it will melt as global temperatures rise. In one of the newest studies, an international team drilled boreholes to measure melt rates and ice movements, finding that the story is even more complicated than we thought.

“Although the Greenland Ice Sheet initially speeds up each summer in its slow-motion race to the sea, the network of meltwater channels beneath the sheet is not necessarily forming the slushy racetrack that had been previously considered,” said Matthew Hoffman, a Los Alamos National Laboratory scientist on the project, which clarifies the evolution of the meltwater flow rates over the seasons. Continue reading

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Climate: Coastal threats should be tackled now

Sea level is rising, and will continue to rise for centuries even if we cut greenhouse gas emissions.

Sea level is rising, and will continue to rise for centuries even if we cut greenhouse gas emissions.

Addressing non-climatic impacts will improve long-term resilience

Staff Report

FRISCO — From mountains, forests and rivers down to the seashore, a common theme among researchers is that, in many places, human impacts stemming from land use and development still outweigh the global warming signal.

That includes coastal regions, were there is an immediate need to tackle the threats from non-climatic changes, an international research team said this week after a detailed review of Intergovernmental Panel on Climate Change assessments. Continue reading

Study tracks historic Antarctica meltdowns

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Reading the history of Antarctica’s ice sheets is helping climate scientists project the future.

Transition from glacial periods punctuated by sudden surges of ice melt and sea level rise

Staff Report

FRISCO — Even without the addition of heat-trapping greenhouse gases from fossil fuel combustion, the Antarctica ice sheets may be vulnerable to sudden collapse and melting. One such episode, about 14,600 years ago, is thought to have caused sea level to rise by more than 12 feet in just 100 years.

Scientists are racing to understand the dynamics of the Antarctic ice sheets because of the potentially significant consequences of rapid changes, and in one of the newest studies, they’ve traced some of the big iceberg calving events between about 19,000 and 9,000 years ago by analyzing deep sea sediment cores extracted from the region between the Falkland Islands and the Antarctic Peninsula. 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

Glacier inventory to help with sea level projections

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The world’s glaciers are dwindling.

CU Boulder scientists help lead mapping effort

Staff Report

FRISCO — Lots of quibbling over the exact rate and pace of glacier melt has at least partly obscured the grim reality that many of the world’s glaciated regions will see profound changes in the next few decades as global temperatures continue to rise.

That meltdown will raise sea level, but so far, nobody has been able to quantify the amount precisely. But new data gathered in a study led by University of Colorado, Boulder scientists should help. The team, including researchers from Trent University in Ontario, Canada recently completed the first mapping of virtually all of the world’s glaciers. That enables calculations of their volumes and ongoing contributions to global sea rise as the world warms. Continue reading

Is the Greenland glacier meltdown partly caused by natural climate variability?

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

Warming temps around Greenland may be partly due to natural climate variability.

New study shows link between Pacific Ocean hotspot and North Atlantic weather patterns

Staff Report

FRISCO — Climate researchers and glaciologists have long been tracking the meltdown of Greenland’s glaciers. The region has been warming at the astounding rate of about 1 degree Celsius per decade — several times the global average — but part of that may be due to natural variability, according to a new study led by University of Washington scientists.

The research suggests up to half the recent warming in the area may be linked with climate patterns born in the tropical western Pacific rather than with the overall warming of the planet. Continue reading

Climate: Antarctica study traces history of Pine Island Glacier melt

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How fast will Antarctica’s Pine Island Glacier melt?

Findings suggest the West Antarctica glacier is very sensitive to environmental change

By Summit Voice

FRISCO — Antarctica’s Pine Island Glacier is likely to remain a significant factor in global sea level rise for decades to come, as a warming ocean melts the ice from beneath.

Geologists from the UK, USA and Germany used highly sensitive dating techniques, pioneered by one of the team, to track the thinning of the glacier through time, and to show that past thinning has lasted for several decades.

Rocks exposed by retreating or thinning glaciers provide evidence of past ice sheet change, which helps scientists to predict possible future change. The research results were published this week in Science. Continue reading

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