Greenland Ice Sheet Destabilizing, Threatening Greater Sea-Level Rise

March 2014   (James Hansen makes the case that sea level could rise over decades)

[My comment: 90% of global trade (much of it food and oil) is carried by container ships and oil-tankers. All of the world’s ports will be affected and most of them overwhelmed by just a 3-foot rise from storm surges.  By 6 feet most harbors will be useless, and the massive shipments of food and oil that allow nations now to maintain populations vastly beyond their carrying capacity will become impossible as sea levels continue to rise for centuries]

“The Greenland ice sheet has contributed more than any other ice mass to sea level rise over the last two decades and has the potential, if it were completely melted to raise global sea level by more than 23 feet,” said Jonathan Bamber, a professor at Britain’s University of Bristol.

A new region of a massive ice sheet in Greenland has become unstable, threatening to raise global sea levels beyond previous estimates, an international team of scientists has found.

The Greenland ice sheet is a 660,000-square mile swath of ice that covers 80% of the country. The second-largest ice sheet in the world behind the Antarctic Ice Sheet, it’s especially vulnerable to global warming, yet its northeast portion had remained largely unaffected by rising temperatures.

Until recently, researchers say.

From April 2003 to April 2012, the northeast portion lost about 10 billion tons of ice per year, according to GPS data.

It’s losing more ice, and the rate is accelerating. The ice loss has accelerated by a factor of three,” says Michael Bevis, a professor at Ohio State University and one of the study’s lead investigators. “That’s a pretty big increase – it’s sort of like the canary in the mine.”

“Northeast Greenland is very cold. It used to be considered the last stable part of the Greenland ice sheet,” explained GNET lead investigator Michael Bevis of The Ohio State University. “This study shows that ice loss in the northeast is now accelerating. So, now it seems that all of the margins of the Greenland ice sheet are unstable.”

Historically, Zachariae drained slowly, since it had to fight its way through a bay choked with floating ice debris. Now that the ice is retreating, the ice barrier in the bay is reduced, allowing the glacier to speed up — and draw down the ice mass from the entire basin.

References

Shfaqat A. Khan, Kurt H. Kjær, Michael Bevis, Jonathan L. Bamber, John Wahr, Kristian K. Kjeldsen, Anders A. Bjørk, Niels J. Korsgaard, Leigh A. Stearns, Michiel R. van den Broeke, Lin Liu, Nicolaj K. Larsen, Ioana S. Muresan. Sustained mass loss of the northeast Greenland ice sheet triggered by regional warming. Nature Climate Change, 2014;
Study: Ice Sheet Destabilizing, Threatening Greater Sea-Level Rise The northeast portion of the Greenland Ice Sheet is melting faster than researchers estimated. Alan Neuhauser. March 16, 2014. US News & World Report