News

Study: Warm Ocean Speeds Antarctic Melting

Water heating ice shelf from below

Warmer ocean water is heating the ice shelves from below. Ice shelves are large masses of ice which stick out from the land over the sea.
Warmer ocean water is heating the ice shelves from below. Ice shelves are large masses of ice which stick out from the land over the sea.

Multimedia

Audio
Rosanne Skirble

Warm water, and not warm air, is speeding the accelerated ice melt in Antarctica, according to a new study in Nature.

The study's lead author, Hamish Pritchard, is a glaciologist with the British Antarctic Survey. In 1993, and again in 2003, he observed the collapse of two ice shelves on the Antarctic Peninsula. He says the glaciers they had been holding back picked up speed and flowed six times faster than normal into the Southern Ocean.

When Pritchard’s team deployed satellite laser instruments to measure changes in the Antarctic ice shelves between 2003 and 2008 they saw a distinct pattern.

“Some of the ice shelves were lowering quite strongly," he says, "and in particular those were the ice shelves in west Antarctica.”

NASA's IceSat satellite measured the changes in ice shelf thickness.
NASA's IceSat satellite measured the changes in ice shelf thickness.

Previous studies looking for the causes of the shrinking ice shelves had ruled out decreased snowfall or any slow-down in the movement of glaciers toward the sea.

Pritchard says the new data points to a process they call “basal melt:” warmer ocean water heating the ice shelf from below.

“We looked at 54 ice shelves around Antarctica and of those, 20 were thinning by this process. Going beyond that we found in every case where we saw this ice shelf thinning by basal melt, we also saw thinning by acceleration of the glaciers that drained from the ice sheet.”

Pritchard says stronger westerly winds in the Southern Ocean are driving warmer ocean currents closer inland to ice shelves on the Antarctic coast. “It tells us that the ice shelves can be very sensitive to quite subtle changes in the climate, such as the wind patterns, that we hadn’t really appreciated before.”

Jan Gunnar Winther, director of the Norwegian Polar Institute, is not affiliated with the study. He says the research provides important new insight into how climate change-induced melting of the Earth’s polar ice sheets is affecting global sea levels.

“In very many places around the world, most places where you have glaciers, and in Greenland, in parts of Antarctica, not in all of Antarctica, they add to the global sea level and they may already be, from what we know, the most important explanation of why we have an increased sea level."

Winther says emissions from fossil-fuel combustion in our power plants, cars and buildings continue to pump global warming gases into the atmosphere. As Prichard and colleagues note in their Nature study, these warming trends are driving wind and ocean current changes that are speeding up the melting and thinning of Antarctic ice.

That dynamic appears to be self-sustaining, the researchers warn, concluding that it “may have already triggered a period of unstable glacier retreat” across the western Antarctic ice sheet.

This forum has been closed.
Comment Sorting
Comments
     
by: Stu Mac
May 04, 2012 8:20 AM
Doesn't everyone know that Antarctica is just a big ice cube that naturally cools down our oceans? The ocean is warm so the glacier slices a bit off the cool it down again. It works like an air conditioner. When the house gets warm the ac cools it down.

by: Katherine Balinki
May 03, 2012 4:27 PM
This si a great article!! Very informative and interesting!!

by: Jermaine
May 03, 2012 8:15 AM
I think this sucks because we have the possibbility to change these problems, and we don´t do anything for change this.

by: Guillermo Eduardo Mannucci
May 02, 2012 12:47 PM
I wish to propose ideas to the USA on enviroment conservation: why not to promote the electfric supply in factories and big comercial stores with energy from sunlights pannels during days and afternoons, and electrical power from energy power plants all whole nights? sun pannels buyins just by once. thanks

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Nobel Prize Winner Malala Talks to VOAi
X
August 31, 2015 2:17 AM
Nobel Peace Prize winner Malala Yousafzai met with VOA's Deewa service in Washington Sunday to talk about women’s rights and unveil a trailer for her new documentary. VOA's Katherine Gypson has more.
Video

Video Nobel Prize Winner Malala Talks to VOA

Nobel Peace Prize winner Malala Yousafzai met with VOA's Deewa service in Washington Sunday to talk about women’s rights and unveil a trailer for her new documentary. VOA's Katherine Gypson has more.
Video

Video War, Drought Threaten Iraq's Marshlands

Iraq's southern wetlands are in crisis. These areas are the spawning ground for Gulf fisheries, a resting place for migrating wildfowl, and source of livelihood for fishermen and herders. Faith Lapidus has more.
Video

Video Colombians Flee Venezuela as Border Crisis Escalates

Hundreds of Colombians have fled Venezuela since last week, amid an escalating border crisis between the two countries. Last week, Venezuelan President Nicolas Maduro ordered the closure of a key border crossing after smugglers injured three Venezuelan soldiers and a civilian. The president also ordered the deportation of Colombians who are in Venezuela illegally. Zlatica Hoke reports.
Video

Video Rebuilding New Orleans' Music Scene

Ten years after Hurricane Katrina inundated New Orleans, threatening to wash away its vibrant musical heritage along with its neighborhoods, the beat goes on. As Bronwyn Benito and Faith Lapidus report, a Musicians' Village is preserving the city's unique sound.
Video

Video In Russia, Auto Industry in Tailspin

Industry insiders say country relies too heavily on imports as inflation cuts too many consumers out of the market. Daniel Schearf has more from Moscow.
Video

Video Scientist Calls Use of Fetal Tissue in Medical Research Essential

An anti-abortion group responsible for secret recordings of workers at a women's health care organization claims the workers shown are offering baby parts for sale, a charge the organization strongly denies. While the selling of fetal tissue is against the law in the United States, abortion and the use of donated fetal tissue for medical research are both legal. VOA’s Julie Taboh reports.
Video

Video Next to Iran, Climate at Forefront of Obama Agenda

President Barack Obama this week announced new initiatives aimed at making it easier for Americans to access renewable energy sources such as solar and wind. Obama is not slowing down when it comes to pushing through climate change measures, an issue he says is the greatest threat to the country’s national security. VOA correspondent Aru Pande has more from the White House.
Video

Video Arctic Draws International Competition for Oil

A new geopolitical “Great Game” is underway in earth’s northernmost region, the Arctic, where Russia has claimed a large area for resource development and President Barack Obama recently approved Shell Oil Company’s test-drilling project in an area under U.S. control. Greg Flakus reports.
Video

Video Philippine Maritime Police: Chinese Fishermen a Threat to Country’s Security

China and the Philippines both claim maritime rights in the South China Sea.  That includes the right to fish in those waters. Jason Strother reports on how the Philippines is catching Chinese nationals it says are illegal poachers. He has the story from Palawan province.
Video

Video China's Spratly Island Building Said to Light Up the Night 'Like A City'

Southeast Asian countries claim China has illegally seized territory in the Spratly islands. It is especially a concern for a Philippine mayor who says Beijing is occupying parts of his municipality. Jason Strother reports from the capital of Palawan province, Puerto Princesa.
Video

Video Ages-old Ice Reveals Secrets of Climate Change

Ice caps don't just exist at the world's poles. There are also tropical ice caps, and the largest sits atop the Peruvian Andes - but it is melting, quickly, and may be gone within the next 20 years. George Putic reports scientists are now rushing to take samples to get at the valuable information about climate change locked in the ice.

VOA Blogs