NASA: Rapid Ice Sheet Melting

The pace at which the Greenland and Antarctic ice sheets are melting is “accelerating rapidly” and raising the global sea level, according to findings of a study financed by NASA, suggesting that the ice sheets – more so than ice loss from Earth’s mountain glaciers and ice caps – have become “the dominant contributor to global sea level rise, much sooner than model forecasts have predicted”.

In the Age March 9, 2011 – 3:19PM

AFP

The pace at which the Greenland and Antarctic ice sheets are melting is “accelerating rapidly” and raising the global sea level, according to findings of a study financed by NASA.

The findings suggest that the ice sheets – more so than ice loss from Earth’s mountain glaciers and ice caps – have become “the dominant contributor to global sea level rise, much sooner than model forecasts have predicted”.

This study, published on Tuesday, the longest to date examining changes to polar ice sheet mass, combined two decades of monthly satellite measurements with regional atmospheric climate model data to study changes in mass.

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“That ice sheets will dominate future sea level rise is not surprising – they hold a lot more ice mass than mountain glaciers,” said lead author Eric Rignot, jointly of NASA’s Jet Propulsion Laboratory and the University of California, Irvine.

“What is surprising is this increased contribution by the ice sheets is already happening,” he said.

Under the current trends, he said, sea level is likely to be “significantly higher” than levels projected by the United Nations climate change panel in 2007.

Isabella Velicogna, co-author of the study, told AFP that the ice sheets lose mass by melting or by breaking apart in blocks of ice, which float into the ocean.

“It’s related to the warming of the planet but that was not the point of the paper. We just observed the changes,” said Velicogna, a professor at UC Irvine. “It’s losing mass – much more than was expected many years ago.”

The study showed that in 2006, a year in which comparable results for loss from mountain glaciers and ice caps are available, the Greenland and Antarctic ice sheets lost enough mass to raise global sea level by an average of 1.3mm per year.

The year-on-year acceleration rate of loss on mountain glaciers and ice caps was three times smaller than that of the ice sheets, the study said.

“The authors conclude that, if current ice sheet melting rates continue for the next four decades, their cumulative loss could raise sea level by 15cm by 2050,” the report said.

“When this is added to the predicted sea level contribution of 8cm from glacial ice caps and 9cm from ocean thermal expansion, total sea level rise could reach 12.6 inches (32 centimetres),” it said.

The findings were published the March edition of Geophysical Research Letters.

Source: www.news.theage.com.au

By Wendy Koch, USA TODAY ( 8 March 2011)

American skepticism about whether the world’s weather is changing depends partly on wording. More believe in “climate change” than “global warming,” a new study by the University of Michigan shows.

Three of four people, or 74%, thought the problem was real when it was referred to as climate change, while 68% thought it was real when it was called global warming, according to questions posed by U-M psychologists on a RAND-conducted survey of 2,267 U.S. adults..

“Wording matters,” study co-author Jonathon Schuldt said in announcing the findings, which will be published in the upcoming issue of Public Opinion Quarterly. “While global warming focuses attention on temperature increases, climate change focuses attention on more general changes,” he said. “Thus, an unusually cold day may increase doubts about global warming more so than about climate change.”

The study found the differences were due almost entirely to participants who identified themselves as Republicans. While 60% of Republicans said they thought climate change was real, only 44% said they believed in the reality of global warming. In contrast, 86% of Democrats thought climate change was a serious problem, regardless of wording.

“It might be a ceiling effect, given their high level of belief,” co-author Sara Konrath, a U-M psychologist, speculated. “Or it could be that Democrats’ beliefs about global climate change might be more crystallized, and as a result, more protected from subtle manipulations.”

The good news, the study says, is that Americans may not be as polarized on the issue as previously thought. “When the issue is framed as global warming, the partisan divide is nearly 42 percentage points. But when the frame is climate change, the partisan divide drops to about 26 percentage points.” said the third author, Norbert Schwarz, who is also affiliated with the U-M Ross Business School and the Institute of Social Research.

As part of the study, the researchers also analyzed the use of the two terms by political think tank websites. They found that conservative groups tend to call the phenomenon global warming, while liberal ones call it climate change.

Source: www.content.usatoday.com