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

Environmental

USCG Flush Ice down River Systems to Facilitate Shipping

The Coast Guard cutter fleet is flushing ice through the Great Lakes river systems to prevent ice jams and facilitate commercial shipping as the shipping season

Chile Desert Rains Sign of Climate Change

The heavy rainfall that battered Chile's usually arid north this week happened because of climate change, a senior meteorologist said, as the region gradually

Mexico Unveils National Strategy ahead of Paris Climate Talks

Mexico on Friday said it will cap its greenhouse gas emissions by 2026, becoming one of the first countries to formally submit its national climate plan the

News

Gulf Bridge Express Service to End

The Gulf Bridge Express Service will shortly be terminated with the last roundtrip voyage being MV Saint Nikolaos voyage 00008S, ETA New Orleans on April 22, 2015.

Obangame Express 2015 Concludes in the Gulf of Guinea

Maritime forces from Gulf of Guinea nations, Europe, South America, and the United States and several regional and international organizations concluded the multinational maritime exercise,

Scandlines Ferry Back in Service by End June

The damaged Scandlines ferry M/V Prinsesse Benedikte is being repaired at the Polish shipyard Remontowa and is expected to be ready before the end of June 2015.

Marine Science

US Navy to Roll out Underwater Spy Satellites

The robotic series that remade crusade in skies will shortly extend to a low sea, with underwater view “satellites,” drone-launching pods on a sea building and unmanned ships sport submarines,

Changes in Aker Solutions' Top Deck

Tore Sjursen will assume the position as executive vice president for operational improvement and risk management at Aker Solutions on April 1. Knut Sandvik

Salvage, Wreck Removal Beset with Chronic Problems

The basic nature of maritime casualties, salvage and wreck removal has evolved rapidly over the last few years. Ships and offshore constructions have become more technologically elaborate,

Arctic Operations

USA Urged Not to Delay Arctic Drilling

The U.S. should immediately begin a push to exploit its enormous trove of oil in the Arctic waters off of Alaska, or risk a renewed reliance on imported oil in the future, reports AP.

Nations Convene for Arctic Maritime Discussion

Citing an increasing need to ensure safety, security and stewardship of Arctic waters, member countries of the Arctic Council gathered at U.S. Coast Guard Headquarters

Statoil: Polarled Pipe-Laying Kicks Off

On 26 March, the Solitaire pipe-laying vessel started on the first stage of the Polarled installation project. The 482-kilometre long pipeline will transport gas

Ocean Observation

US Navy to Roll out Underwater Spy Satellites

The robotic series that remade crusade in skies will shortly extend to a low sea, with underwater view “satellites,” drone-launching pods on a sea building and unmanned ships sport submarines,

China Unveils Action Plan on Maritime Silk Road

China has unveiled the principles, framework, and cooperation priorities and mechanisms in its Maritime Silk Road initiative in a bid to enhance regional connectivity

China Maritime Silk Road to Touch India for Namesake

Chinese officials on Saturday fleshed out some details for the country's ambitious 21st Century Maritime Silk Road (MSR) project in its “one belt, one road,” action plan.

 
 
Maritime Careers / Shipboard Positions Maritime Contracts Maritime Security Navigation Offshore Oil Pipelines Ship Repair Ship Simulators Shipbuilding / Vessel Construction Sonar
rss | archive | history | articles | privacy | terms and conditions | 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: 0.2888 sec (3 req/sec)