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Tropical sea temperatures influence melting in Antarctica

Higher-than-normal sea-level pressure Accelerated melting of two fast-moving outlet glaciers that drain Antarctic ice into the Amundsen Sea Embayment is likely the result, in part, of an increase in sea-surface temperatures in the tropical Pacific Ocean, according to new University of Washington research.Higher-than-normal sea-level pressure north of the Amundsen Sea sets up westerly winds that push surface water away from the glaciers and allow warmer deep water to rise to the surface under the edges of the glaciers, said Eric Steig, a UW professor of Earth and space sciences."This part of Antarctica is affected by what's happening on the rest of the planet, in particular the tropical Pacific," he said.The research involves the Pine Island and Thwaites glaciers on the West Antarctic Ice Sheet, two of the five largest glaciers in Antarctica. Those two glaciers are important because they drain a large portion of the ice sheet.As they melt from below, they also gain speed, draining the ice sheet faster and contributing to sea level rise. Eventually that could lead to global sea level rise of as much as 6 feet, though that would take hundreds to thousands of years, Steig said.NASA scientists recently documented that a section of the ...

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Simultaneous ice melt in Antarctic and Arctic

They attained their max ice sheet size at nearly the same time and started melting 19,000 years ago The end of the last ice age and the processes that led to the melting of the northern and southern ice sheets supply basic information on changes in our climate.Although the maximum size of the ice sheet in the northern hemisphere during the last ice age is relatively well known, there is little reliable data on the dimensions of the Antarctic ice sheet.A publication appearing in the journal "Science" on 1 December now furnishes indications that the two hemispheres attained their maximum ice sheet size at nearly the same time and started melting 19,000 years ago."The decline in the Antarctic ice sheets thus commenced almost 5,000 years earlier than assumed to date, though our investigations show great regional differences and demonstrate how important deepwater archives are," says the lead author of the study, Dr. Michael Weber from the Geological Institute of the University of Cologne."Our results suggest that Antarctica was not as climatically isolated as previously assumed," adds Dr. Gerhard Kuhn from the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association. "Now we have to presume that the ...

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Arctic Report Card 2011

Tracking recent environmental changes Arctic Report Card: Update for 2011 - Tracking recent environmental changes, with 23 essays on different aspects of the environment, by a team of 112 international authors, and independently peer-reviewed by the Arctic Monitoring and Assessment Programme of the Arctic Council.

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Arctic Sea Ice Decline Greatest, Longest In 1,450 Years

more in the last half-century than it has any time over the last 1,450 years.! Research published in a top scientific journal says Arctic sea ice has declined more in the last half-century than it has any time over the last 1,450 years.The study, which gives the most detailed picture ever of the northern oceans over the previous millennium-and-a-half, also concludes the current decline has already lasted longer than any previous one in that period."When we look at our reconstruction, we can see that the decline that has occurred in the last 50 years or so seems to be unprecedented for the last 1,450 years," Christian Zdanowicz of the Geological Survey of Canada said Wednesday."It's difficult not to come up with the conclusion that greenhouse gases must have something to do with this," added Zdanowicz, one of the co-authors of the report in Nature."We cannot account for this decline by processes that are 'natural.'"Climate change is thought to be occurring faster in the Arctic than anywhere else on Earth and sea ice is considered one of the main indicators. The ice is crucial in northern ecosystems because it provides habitat for everything from plankton to polar bears.Its gradual disappearance is ...

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International Team to Drill Beneath Massive Antarctic Ice Shelf

This science expedition will be the most extensive ever deployed to Pine Island Glacier. An international team of researchers funded by NASA and the National Science Foundation (NSF) will travel next month to one of Antarctica's most active, remote and harsh spots to determine how changes in the waters circulating under an active ice sheet are causing a glacier to accelerate and drain into the sea.The science expedition will be the most extensive ever deployed to Pine Island Glacier. It is the area of the ice-covered continent that concerns scientists most because of its potential to cause a rapid rise in sea level. Satellite measurements have shown this area is losing ice and surrounding glaciers are thinning, raising the possibility the ice could flow rapidly out to sea.The multidisciplinary group of 13 scientists, led by Robert Bindschadler, emeritus glaciologist of NASA's Goddard Space Flight Center in Greenbelt, Md., will depart from the McMurdo Station in Antarctica in mid-December and spend six weeks on the ice shelf. During their stay, they will use a combination of traditional tools and sophisticated new oceanographic instruments to measure the shape of the cavity underneath the ice shelf and determine how streams of warm ocean ...

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Arctic sea ice to melt by 2015

Destroying the natural habitat of animals like polar bears, Prof Peter Wadhams, of Cambridge University, said the ice that forms over the Arctic sea is shrinking so rapidly that it could vanish altogether in as little as four years' time.Although it would reappear again every winter, its absence during the peak of summer would rob polar bears of their summer hunting ground and threaten them with extinction.The mass of ice between northern Russia, Canada and Greenland waxes and wanes with the seasons, currently reaching a minimum size of about four million square kilometres.Most models, including the latest estimates by the Intergovernmental Panelon Climate Change (IPCC), track the decline in the area covered by ice in recent years to predict the rate at which it will deteriorate.But citing research compiled by Dr Wieslaw Maslowski, a researcher from the American Naval Postgraduate School, last year Prof Wadhams said such predictions failed to spot how quickly climate change is causing the ice to thin.While the IPCC suggests the ice will remain in place until the 2030s, Dr Maslowski's study also takes into account the rate at which it is thinning and calculates that it will vanish much more quickly.Dr Maslowski's model, along with ...

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