Feeds

Previously stable Greenland glaciers now rushing to the sea

Time to revise those projections of sea-level rise – upward

The next step in data security

A trio of glaciers in a vast region of northeastern Greenland previously thought to be stable are thinning and moving into the sea, forcing climate scientists to reevaluate their projections of sea-level rise upward.

"We're seeing an acceleration of ice loss," study coauthor Michael Bevis of Ohio State University told USA Today. "Now, there's more ice leaving than snow arriving."

Bevis and his team's research was published on Sunday in Nature Climate Change in a paper titled "Sustained mass loss of the northeast Greenland ice sheet triggered by regional warming."

Specifically, the paper reports that "the northeast Greenland ice stream, which extends more than 600 km into the interior of the ice sheet, is now undergoing sustained dynamic thinning, linked to regional warming, after more than a quarter of a century of stability."

This thinning and accelerating flow of the northeastern Greenland ice stream (NEGIS) "surprised everyone," Bevis said, seeing as how NEGIS had been relatively stable for a quarter century before "rapid dynamic thinning start[ed] some time between 2003 and 2006," as the paper reports, as ocean-surface ice melted and no longer blocked their advance.

Satellite image of Greenland, North America, and Wester Europe

Northeastern Greenland is so cold that its ice stream was thought to have been stable – until now

The team determined the thinning by conducting a wide range of different observations, including satellite and aircraft sensor readings and photographs, and bedrock-mounted GPS units that detect deformations in that bedrock due to changes in the weight of the ice sheet.

Taken together, the data points to the same conclusion: NEGIS is on the move, and its ice is finding its way into the sea, contributing to a sea-level rise. What's more, the loss of seaborne ice blocking the glaciers is allowing comparatively "warm subsurface ocean water" to slip between the glaciers and bedrock, contributing to "further instability near the grounding line."

NEGIS and its three outlet glaciers – the Nioghalvfjerdsfjorden Glacier (also called 79 North), Zachariae Isstrøm, and Storstrømmen Glacier – are not to be confused with the Jakobshavn Isbræ (Danish for "glacier") in western Greenland, which as The Reg reported last month, is already known to be accelerating and increasing its contribution to sea-level rise.

Referring to NEGIS, the paper notes that "this sector of the Greenland ice sheet is of particular interest, because the drainage basin area covers 16 per cent of the ice sheet (twice that of Jakobshavn Isbræ)." It's also of particular interest because since NEGIS and its three-outlet glaciers had been thought to be stable, their contribution to sea-level rise has not been factored into existing models, which will now need to be revised – upward.

The Jakobshavn Isbræ remains the badass when it comes to glacial melt into the ocean, contributing approximately 30 metric gigatons of water into the sea each year, on average. That said, NEGIS' Zachariae Isstrøm is already contributing around 10 metric gigatons per year now – up from nothing just a few years back – and one of the paper's coauthors, Shfaqat Khan of the Technical University of Denmark, told E&E that ice loss in northeastern Greenland is now 15 to 20 metric gigatons and increasing.

"This is the first time anyone has ever observed a sudden acceleration of ice loss in the downhill (outlet) portions of a really long ice stream," Ohio States' Bevis told Mashable. "So, we are in terra incognito."

That said, the paper's conclusion is sobering. "As recent model projections suggest, ocean warming around Greenland may reach almost double the global mean by 2100 and the recent assessment report of snow, water, ice and permafrost in the Arctic projects the largest and most pronounced air temperature increase over northeast Greenland, increasing the risk of continued mass loss from this sector of Greenland."

About those IPCC sea-level projections? Apparently climate scientists now need to tweak their models. ®

New hybrid storage solutions

More from The Register

next story
PORTAL TO ELSEWHERE scried in small galaxy far, far away
Supermassive black hole dominates titchy star formation
Bacon-related medical breakthrough wins Ig Nobel prize
Is there ANYTHING cured pork can't do?
Boffins say they've got Lithium batteries the wrong way around
Surprises at the nano-scale mean our ideas about how they charge could be all wrong
Edge Research Lab to tackle chilly LOHAN's final test flight
Our US allies to probe potential Vulture 2 servo freeze
Europe prepares to INVADE comet: Rosetta landing site chosen
No word yet on whether backup site is labelled 'K'
Cracked it - Vulture 2 power podule fires servos for 4 HOURS
Pixhawk avionics juice issue sorted, onwards to Spaceport America
Archaeologists and robots on hunt for more Antikythera pieces
How much of the world's oldest computer can they find?
prev story

Whitepapers

Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Beginner's guide to SSL certificates
De-mystify the technology involved and give you the information you need to make the best decision when considering your online security options.