melting ice sheet

washingtonpost.com
In Greenland, a once doubtful scientist witnesses climate change's troubling toll
Petermann glacier has lost huge ice islands since 2010, and Andreas Muenchow thinks another break is coming.

Half a decade before he took this trip to the farthest reaches of the north, Andreas Muenchow had his doubts about whether warming temperatures were causing one of the world’s great platforms of ice to melt and fall apart.

He even stood before Congress in 2010 and balked on whether climate change might have caused a mammoth chunk of ice, four times the size of Manhattan, to break off from this floating, 300-square-mile shelf. The University of Delaware oceanographer said he wasn’t sure. He needed more evidence.

But then the Petermann Ice Shelf lost another two Manhattans of ice in 2012, and Muenchow decided to see for himself, launching a project to study the ice shelf intensively.

He was back again in late August, no longer a skeptic. It was hard not to be a believer here at 81 degrees north latitude, where Greenland and Canada very nearly touch. The surface of the bumpy and misshapen ice was covered with pools and puddles, in some cases frozen over but with piercing blue water beneath. Streams carved through the vast shelf, swelling into larger ponds or even small lakes.

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Alive and Well: Microbes Add to Melting of Greenland Ice Sheet.  

Scientists are investigating a new “positive feedback” in Greenland’s melting ice sheet - as climate warms, more microbial growth on the ice sheet is darkening ice, and hastening ice melt and sea level rise.

YaleClimateConnections

Greenland is Melting Away

This river is one of a network of thousands at the front line of climate change.

 By NYTimes: Coral Davenport, Josh Haner, Larry Buchanan and Derek Watkins                                    

On the Greenland Ice Sheet — The midnight sun still gleamed at 1 a.m. across the brilliant expanse of the Greenland ice sheet. Brandon Overstreet, a doctoral candidate in hydrology at the University of Wyoming, picked his way across the frozen landscape, clipped his climbing harness to an anchor in the ice and crept toward the edge of a river that rushed downstream toward an enormous sinkhole.

If he fell in, “the death rate is 100 percent,” said Mr. Overstreet’s friend and fellow researcher, Lincoln Pitcher.

But Mr. Overstreet’s task, to collect critical data from the river, is essential to understanding one of the most consequential impacts of global warming. The scientific data he and a team of six other researchers collect here could yield groundbreaking information on the rate at which the melting of the Greenland ice sheet, one of the biggest and fastest-melting chunks of ice on Earth, will drive up sea levels in the coming decades. The full melting of Greenland’s ice sheet could increase sea levels by about 20 feet. [bold/itals mine]

“We scientists love to sit at our computers and use climate models to make those predictions,” said Laurence C. Smith, head of the geography department at the University of California, Los Angeles, and the leader of the team that worked in Greenland this summer. “But to really know what’s happening, that kind of understanding can only come about through empirical measurements in the field.”

For years, scientists have studied the impact of the planet’s warming on the Greenland and Antarctic ice sheets. But while researchers have satellite images to track the icebergs that break off, and have created models to simulate the thawing, they have little on-the-ground information and so have trouble predicting precisely how fast sea levels will rise.

Dire report by three excellent Times journalists covering a team of researchers camped out on the icesheets of Greenland. The conclusion is that glaciers and land ice are melting at rates far higher than scientists anticipated, or that climate models have shown. This means that sea levels are rising faster than projected, and many coastal communities are in grave danger.

The economic impacts are incalculable.

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Greenland ice sheet’s “extreme melt event” shatters temperature records, stuns scientists

Seasonal melt is normal in Greenland: Parts of the ice sheet melt each spring and then freeze again when the weather gets cold. But this year, when climate scientists at the Danish Meteorological Institute began to measure the seasonal melt, the data was unlike anything they had ever seen before. Here’s how much higher the temperature is compared to last year.

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