Sunnier Skies Driving Greenland Surface Melt

Sunnier Skies Driving Greenland Surface Melt

SOURCE: Climate Central DATE: June 28, 2017 SNIP: In the past two decades, the Greenland ice sheet has become the biggest single contributor to rising sea levels, mostly from melt across its vast surface. That surface melt is, in turn, driven mostly by an uptick in clear, sunny summer skies, not just rising air temperatures, a new study finds. While some of the water Greenland is flushing out to sea comes from warming ocean waters lapping away at the glaciers that drain the ice sheet, most is due to the melt across its surface during the summer. Stefan Hofer, a PhD candidate at the University of Bristol in England, and his colleagues looked into what the main drivers of that surface melt were, in particular the effect of cloud cover on melt. In satellite data spanning the past two decades, they saw a significant decrease in cloud cover over Greenland starting in the mid-90s, which would mean more sunlight was falling on the ice and driving melt. Climate models the team used suggest that every 1 percent reduction in cloud cover leads to another 27 gigatons of melt (the U.S. uses about 1.3 gigatons of water per day, according to data from NASA and the U.S. Geological Survey). That sensitivity to cloud cover was “pretty astounding,” William Colgan, a senior researcher with the Geological Survey of Denmark and Greenland who wasn’t involved in the study, said in an...
Scientists just uncovered some troubling news about Greenland’s most enormous glacier

Scientists just uncovered some troubling news about Greenland’s most enormous glacier

SOURCE: Washington Post DATE: April 11, 2017 SNIP: The largest glacier in Greenland is even more vulnerable to sustained ice losses than previously thought, scientists have reported. Jakobshavn glacier, responsible for feeding flotillas of icebergs into the Ilulissat icefjord — and possibly for unleashing the iceberg that sank the Titanic — is an enormous outlet for the larger Greenland ice sheet, which itself contains enough ice to raise seas by more than 20 feet. But until now, researchers have not been sure how far Jakobshavn’s ice extends below sea level — or how much deeper it gets further inland. That’s crucial because Jakobshavn is undergoing a dangerous “marine ice sheet instability,” in which oceanfront glaciers that grow deeper further inland are prone to unstoppable retreat down what scientists call a “retrograde” slope. That’s where the new science comes in: Researchers who flew over Jakobshavn in a helicopter toting a gravimeter, used to detect the gravitational pull of the ice and deduce its mass, say they’ve found the glacier extends even deeper below sea level than previously realized, a configuration that sets the stage for further retreat. “The way the bed looks, sort of makes it more prone to continuous retreat for decades to come,” said one of the study’s authors, Eric Rignot, a researcher with NASA’s Jet Propulsion Laboratory and the University of...
Unusually large swarm of icebergs drifts into shipping lanes

Unusually large swarm of icebergs drifts into shipping lanes

SOURCE: Associated Press DATE: April 5, 2017 SNIP: More than 400 icebergs have drifted into the North Atlantic shipping lanes over the past week in an unusually large swarm for this early in the season, forcing vessels to slow to a crawl or take detours of hundreds of miles. Experts are attributing it to uncommonly strong counter-clockwise winds that are drawing the icebergs south, and perhaps also global warming, which is accelerating the process by which chunks of the Greenland ice sheet break off and float away. As of Monday, there were about 450 icebergs near the Grand Banks of Newfoundland, up from 37 a week earlier, according to the U.S. Coast Guard’s International Ice Patrol in New London, Connecticut. Those kinds of numbers are usually not seen until late May or early June. The average for this time of year is about...
As Arctic warms, Canada’s glaciers playing major role in sea level rise

As Arctic warms, Canada’s glaciers playing major role in sea level rise

SOURCE: CBC News DATE: February 20, 2017 SNIP: Canada’s glaciers are responding rapidly to a warming Arctic and are a major contributor to sea level rise, a new study suggests. Researchers from the University of California Irvine studied data collected from 1991 to 2015 on glaciers found in the Queen Elizabeth Islands in the Arctic. They found that, from 2005 to 2015, surface melt off of these glaciers rose by 900 per cent — something they say is attributable to warming air temperatures in the region. They have gone from shedding three gigatons of water annually to 30 gigatons — something that has serious...
‘Beyond the extreme’: Scientists marvel at ‘increasingly non-natural’ Arctic warmth

‘Beyond the extreme’: Scientists marvel at ‘increasingly non-natural’ Arctic warmth

SOURCE: Washington Post DATE: Feb 1, 2017 AUTHOR: Jason Samenow SNIP: The Arctic is so warm and has been this warm for so long that scientists are struggling to explain it and are in disbelief. The climate of the Arctic is known to oscillate wildly, but scientists say this warmth is so extreme that humans surely have their hands in it and may well be changing how it operates. Temperatures are far warmer than ever observed in modern records, and sea ice extent keeps setting record...