CCTV.com - CNTV English - CCTV News

Warming ocean layers will undermine polar ice sheets: study

07-04-2011 10:20 BJT

LOS ANGELES, July 3 (Xinhua) -- Warming of the ocean's subsurface layers will melt underwater portions of the Greenland and Antarctic ice sheets faster than previously thought, increasing the sea level more than already projected, a new study suggests.

The subsurface ocean layers surrounding the polar ice sheets will warm substantially as global warming progresses, according to the study led by researchers from the University of Arizona (UA).

In addition to being exposed to warming air, underwater portions of the polar ice sheets and glaciers will be bathed in warming seawater, said the study appearing on the website of the American Association for the Advancement of Science (AAAS) on Sunday.

The research, based on 19 state-of-the-art climate models, proposes a new mechanism by which global warming will accelerate the melting of the great ice sheets during this century and the next.

"To my knowledge, this study is the first to quantify and compare future ocean warming around the Greenland and the Antarctic ice sheets using an ensemble of models," said lead author Jianjun Yin, a UA assistant professor of geosciences.

According to the study, the subsurface ocean along the Greenland coast could increase as much as 3.6 F (2 C) by 2100.

Most previous research has focused on how increases in atmospheric temperatures would affect the ice sheets, he said.

"Ocean warming is very important compared to atmospheric warming because water has a much larger heat capacity than air," Yin said. "If you put an ice cube in a warm room, it will melt in several hours. But if you put an ice cube in a cup of warm water, it will disappear in just minutes."

Given a mid-level increase in greenhouse gases, the researchers found the ocean layer about 650 to 1,650 feet (200 to 500 meters) below the surface would warm, on average, about 1.8 F (1 C) by 2100. Along the Greenland coast, that layer would warm twice as much, but along Antarctica would warm less, only 0.9 F (0.5 C).

"No one has noticed this discrepancy before -- that the subsurface oceans surrounding Greenland and Antarctica warm very differently," Yin said.

Part of the warming in the North comes from the Gulf Stream carrying warm subtropical waters north. By contrast, the Antarctic Circumpolar Current blocks some of the subtropical warmth from entering the Antarctic's coastal waters.

Even so, the Antarctic ice sheet will be bathed in warming waters, according to the study.

This paper adds to the evidence that sea level would rise by the end of this century by around one meter and a good deal more in succeeding centuries, the study noted.

The study, "Different Magnitudes of Projected Subsurface Ocean Warming Around Greenland and Antarctica," is scheduled for the upcoming edition of Nature Geoscience later this month.

Editor:Li Wanran |Source: Xinhua

Hot Videos view more

The celebrations are still continuing as the victorious coach, Joachim Loew, has been honored for his achievement in his hometown of Freiburg.
Germany coach Loew honored in hometown of Freiburg

Chinese men´s national team continued its preparations for next year´s Asian Cup, as they managed a one-all draw against visitors Jordan during a football friendly in Harbin, the capital city of Northeast China´s Heilongjiang Province.
China held to 1-1 draw by Jordan

The defending world champs came into the contest with a perfect 6-and-oh record, but they would be in for a tough first half before opening things up in the second.
USA beat Slovenia 119-76 in quarter-finals

Hot Stories more

UK authorities believe killer of James Foley is a British national

Across the UK the hunt is on for James Foley’s killer, who authorities believe is a British national. As Richard Bestic reports from London, Prime Minister David Cameron cut short his summer break to lead his government’s response.

Israeli war jets renews Gaza strike as truce talks stalled

Three Palestinians were killed and 40 others wounded in the intensive Israeli war jets´ airstrikes on the Gaza city on Tuesday night, shortly before an end of a 24-hour ceasefire in the Gaza Strip,

Missouri police arrest dozens after violent night

As the protests in the town of Ferguson, Missouri turned violent with police facing ´heavy gunfire´ from some ´criminal elements´, cops fired tear gas, stun grenades and arrested 31 demonstrators on Monday night.

Picture in news more

More Video News

Choose TV Program