Tuesday, July 5, 2011

Warming Ocean Layers Will Undermine Polar Ice Sheets, Climate Models Show

Warming of the ocean's subsurface layers will melt underwater portions of the Greenland and Antarctic ice sheets faster than previously thought, according to new University of Arizona-led research. Such melting would increase the sea level more than already projected.


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.

The subsurface ocean layers surrounding the polar ice sheets will warm substantially as global warming progresses, the scientists found. In addition to being exposed to warming air, underwater portions of the polar ice sheets and glaciers will be bathed in warming seawater.

The subsurface ocean along the Greenland coast could increase as much as 3.6 °F (2 °C) by 2100.

"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.

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."
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Location:Cayman Islands