Scientists Say Antarctic Glaciers in 'Irreversible' Thaw

Posted by Eric Haun
Monday, May 12, 2014
Image credit: British Antarctic Survey

Vast glaciers in West Antarctica seem to be locked in an irreversible thaw linked to global warming that may push up sea levels for centuries, scientists said on Monday.

Six glaciers, eaten away from below by a warming of sea waters around the frozen continent, were flowing fast into the Amundsen Sea, according to the report based partly on satellite radar measurements from 1992 to 2011.

Evidence shows "a large sector of the West Antarctic ice sheet has gone into a state of irreversible retreat", said lead author Eric Rignot of the University of California, Irvine, and NASA's Jet Propulsion Laboratory in Pasadena, California.

The coastal ends of the glaciers rest on bedrock below sea level, holding back a vast weight of ice and making them vulnerable to melt, he said. He likened the process to uncorking a full bottle of wine while it was lying on its side.

This part of Antarctica would be a major contributor to sea level rise in coming decades and centuries since the glaciers hold enough ice to raise sea levels by 1.2 metres (4 feet).

"It's passed the point of no return," he told a telephone news conference.

Ice-penetrating radars showed no mountain ranges entombed under the ice, for instance, that could halt the flow. The fastest retreat was 34-37 km (21-23 miles) over the period in the Smith/Kohler glacier.

Even so, cuts in greenhouse gas emissions, part of efforts to rein in global warming, could at least slow the slide of the Pine Island, Thwaites, Haynes, Pope, Smith and Kohler glaciers.

"We do think this is related to climate warming," Rignot said. The scientists believed that a build-up of man-made greenhouse gases in the atmosphere was affecting wind patterns around Antarctica, driving warmer waters towards the continent.

Almost 200 nations have agreed to work out a U.N. pact by the end of 2015 to combat global warming, which the U.N. Intergovernmental Panel on Climate Change (IPCC) says will cause more floods, droughts, heat waves and higher seas.

Sea Levels
Monday's findings may also mean that scenarios by the IPCC for sea level rise are too low. The IPCC said last year that sea levels are likely to rise by between 26 and 82 cm (10 and 32 inches) by the late 21st century, after a 19 cm (7 inch) rise since 1900.

"The major ice sheets of this planet will have a larger and larger role in sea level rise in the decades ahead," said Sridhar Anandakrishnan, professor of geosciences at Pennsylvania State University, who was not involved in the study.

Last week, another study also suggested a part of the far bigger ice sheet in East Antarctica may also be more vulnerable than expected to thaw. The IPCC says it is at least 95 percent probable that warming is caused by human activities, led by the burning of fossil fuels.

Monday's study, to be published in the journal Geophysical Research Letters, adds to signs of climate change under way.

On May 6, the Obama administration issued a study saying that warming "once considered an issue for a distant future has moved firmly into the present."

And the IPCC said in March there were signs of irreversible changes to tropical coral reefs and to the Arctic.

A separate study of the Thwaites glacier by the University of Washington in the journal Science also said it may have begun an unstoppable collapse that could last from 200 to 1,000 years.

A disappearance of the Thwaites alone would raise world sea levels by 60 cm (1.96 feet) but the "glacier also acts as a linchpin on the rest of the ice sheet, which contains enough ice to cause another three to four metres of sea level rise", it said.

The findings contrast with a paradoxical expansion of the extent of ice floating on the sea around Antarctica in recent winters that the scientists said may be part of natural variations. "The changes in the glacier reflect much longer-term processes," Tom Wagner, a scientist with NASA's Science Mission Directorate in Washington, said in the telephone briefing.

(By Alister Doyle, Environment Correspondent; Editing by Mark Heinrich)

Maritime Reporter June 2015 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Environmental

New Binding Law of The Sea Agreement Advanced

WOC Sustainable Ocean Summit (Singapore, 9-11 November 2015) Will Enable Industry to Organize its Input to this Major New Ocean Treaty Development The U.N.

Oceans Can’t Take Any more: Researchers Fear Fundamental Change

Our oceans need an immediate and substantial reduction of anthropogenic greenhouse gas emissions. If that doesn’t happen, we could see far-reaching and largely

Ocean Safety, Richard Irvin Marine Safety Merger

Ocean Safety has today announced the merger with Richard Irvin Energy Solutions Marine Safety Division and their Aberdeen branch.   This merger follows the

News

New Binding Law of The Sea Agreement Advanced

WOC Sustainable Ocean Summit (Singapore, 9-11 November 2015) Will Enable Industry to Organize its Input to this Major New Ocean Treaty Development The U.N.

Oceans Can’t Take Any more: Researchers Fear Fundamental Change

Our oceans need an immediate and substantial reduction of anthropogenic greenhouse gas emissions. If that doesn’t happen, we could see far-reaching and largely

Teekay LNG Partners Declares Distribution

Teekay GP LLC, the general partner of Teekay LNG Partners L.P. has declared a cash distribution of $0.70 per unit for the quarter ended June 30, 2015. The cash distribution is payable on August 14,

Marine Science

New Binding Law of The Sea Agreement Advanced

WOC Sustainable Ocean Summit (Singapore, 9-11 November 2015) Will Enable Industry to Organize its Input to this Major New Ocean Treaty Development The U.N.

Technip Samsung JV Wins 2 FLNG Project Contracts

The Browse project covers the realization and installation of three FLNG units to develop the Brecknock, Calliance and Torosa fields in the Browse Basin, 425 kilometers North of Broome,

Ocean Safety, Richard Irvin Marine Safety Merger

Ocean Safety has today announced the merger with Richard Irvin Energy Solutions Marine Safety Division and their Aberdeen branch.   This merger follows the

Arctic Operations

UK Navy’s Ice Patrol Ship Gets a New Coating

U.K. Royal Navy Ice Patrol Ship HMS Protector is deployed on operations for 330 days a year, mostly in the Antarctic region, making it essential that her underwater

Shell Steps Closer to Arctic Drilling

The U.S. Fish and Wildlife Service authorized the nonlethal, incidental, and unintentional take of small numbers of polar bears and Pacific walrus that result

US Issues Potential Setback to Shell's Arctic Drilling

The Obama administration issued a potential setback to Royal Dutch Shell's  Arctic oil exploration plans on Tuesday, telling the company that established wildlife

Ocean Observation

Oceans Can’t Take Any more: Researchers Fear Fundamental Change

Our oceans need an immediate and substantial reduction of anthropogenic greenhouse gas emissions. If that doesn’t happen, we could see far-reaching and largely

HK:Prevention of Ship Garbage Pollution

The Hong Kong SAR Marine Department has advised that on 1 July the existing Merchant Shipping (Prevention of Pollution by Garbage) Regulation (Cap 413J) was replaced by a new Regulation,

Passenger Ferry Capsizes in the Philippines, Nearly 40 Dead

MBCA Kim Nirvana, a passenger boat carrying 189 people has capsized in the central Philippines, minutes after leaving port, the Philippine Red Cross and coast guard spokesman Cmdr.

 
 
Maritime Careers / Shipboard Positions Maritime Contracts Maritime Security Maritime Standards Offshore Oil Pipelines Pod Propulsion Port Authority Ship Electronics Ship Simulators
rss | archive | history | articles | privacy | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.1881 sec (5 req/sec)