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Antarctica's ice loss helps offset global warming: study

Antarctic glacial ice loss unprecedented
Houston (UPI) Nov 10, 2009 - U.S. and British scientists say the current warming and widespread loss of glacial ice on the Antarctic Peninsula is unprecedented. "At no time during the last 14,000 years was there a period of climate warming and loss of ice as large and regionally synchronous as that we are now witnessing in the Antarctic Peninsula," said Steve Bohaty of Britain's National Oceanography Center. Bohaty said the findings are based on a detailed analysis of the thickest Holocene sediment core yet drilled in the Antarctic Peninsula. As part of a 2005 research cruise aboard a U.S. icebreaker, he and his colleagues drilled through sediments to bedrock at Maxwell Bay, a fjord at the Antarctic Peninsula's northwest tip.

The scientists determined there was a period of rapid glacial retreat about 10,000 years ago, followed by reduced sea-ice cover and warm water conditions between 8,200 and 5,900 years ago. But the researchers said an important finding of the study is that the mid-Holocene warming interval does not appear to have occurred synchronously throughout the region, and its timing and duration was most likely influenced at different sites by local oceanographic controls, as well as physical geography. Following the warming interval, the climate gradually cooled during approximately the next 3,000 years or so, resulting in more extensive sea-ice cover in the bay The core also showed the Antarctic Peninsula area has been warming during the last 50 years, with increased rainfall and a widespread retreat of glaciers. The study that included scientists from Rice University, the University of Houston and Vermont's Middleburg College appears in the Geological Society of America Bulletin.
Flights cancelled as Beijing blanketed in snow
Beijing (AFP) Nov 10, 2009 - Nearly 70 flights were cancelled and more than 30 delayed at Beijing's airport Tuesday after the second major snow storm of the season blanketed the Chinese capital, airport officials said. Travel was severely disrupted in the morning as crews removed snow from runways and de-iced planes following an overnight storm that included a few claps of thunder, the airport authority said in a statement. Airport operations returned to normal later in the day, it added. The airport appeared better prepared than on November 1, when the earliest snowfall to hit Beijing in 22 years delayed 200 flights.

Officials readily admitted the first storm was artificially induced, sparking anger among residents whose heat had yet to be switched on. On Tuesday, an official at the Beijing Meteorological Bureau who asked not to be named said: "As far as I know, the snow was not modified - it's natural. Thunder rarely happens in the winter, but it has happened a few times." Beijing was not the only area affected - a large swathe of northern China was covered by snow, shutting down major highways and closing the airport in Shanxi province's Taiyuan city, just west of Beijing, Xinhua news agency said. Meteorologists predict further snowfall in northern China over the next two days, the report said.

by Staff Writers
Paris (AFP) Nov 10, 2009
Global warming has been blamed for the alarming loss of ice shelves in Antarctica, but a new study says newly-exposed areas of sea are now soaking up some of the carbon gas that causes the problem.

Scientists led by Lloyd Peck of the British Antarctic Survey (BAS) said that atmospheric and ocean carbon is being gobbled up by microscopic marine plants called phytoplankton, which float near the surface.

After absorbing the carbon through the natural process of photosynthesis, the phytoplankton are eaten, or otherwise die and sink to the ocean floor.

The phenomenon, known as a carbon sink, has been spotted in areas of open water exposed by the recent, rapid melting of several ice shelves -- vast floating plaques of ice attached to the shore of the Antarctic peninsula.

Over the last 50 years, around 24,000 square kilometres (9,200 square miles) of new open water have been created this way, and swathes of it are now colonised by phytoplankton, Peck's team reports in a specialist journal, Global Change Biology.

Their estimate, based on images of green algal blooms, is that the phytoplankton absorbs 3.5 million tonnes of carbon, equivalent to 12.8 million tonnes of carbon dioxide (CO2), the principal greenhouse gas.

To put it in perspective, this is equivalent to the CO2-storing capacity of between 6,000 and 17,000 hectares (15,000 and 42,500 acres) of tropical rainforest, according to the paper.

The tally is minute compared to the quantities of greenhouse gases from fossil fuels and deforestation, which amounted to 8.7 billion tonnes of carbon in 2007.

But, said Peck, "it is nevertheless an important discovery. It shows nature's ability to thrive in the face of adversity.

"We need to factor this natural carbon absorption into our calculations and models to predict future climate change," he said in a BAS press release.

"So far, we don't know if we will see more events like this around the rest of Antarctica's coast, but it's something we'll be keeping an eye on."

The Antarctic peninsula -- the tongue of land that juts up towards South America -- has been hit by greater warming than almost any other region on Earth.

In the past 50 years, temperatures there have risen by 2.5 degrees Celsius (4.5 degrees Fahrenheit), around six times the global average.

Ice shelves are ledges of thick ice that float on the sea and are attached to the land. They are formed when ice is exuded from glaciers on the land.

In the past 20 years, Antarctica has lost seven ice shelves.

The process is marked by shrinkage and the breakaway of increasingly bigger chunks before the remainder of the shelf snaps away from the coast.

It then disintegrates into debris or into icebergs that eventually melt as they drift northwards.

The Antarctic ice shelves do not add to sea levels when they melt. Like the Arctic ice cap, they float on the sea and thus displace their own volume.

Ice that runs from land into the sea does add, though, to the ocean's volume, which is why some scientists are concerned for the future of the massive icesheets covering Antarctica and Greenland.

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Antarctica Glacier Retreat Creates New Carbon Dioxide Store
London UK (SPX) Nov 10, 2009
Large blooms of tiny marine plants called phytoplankton are flourishing in areas of open water left exposed by the recent and rapid melting of ice shelves and glaciers around the Antarctic Peninsula. This remarkable colonisation is having a beneficial impact on climate change. As the blooms die back phytoplankton sinks to the sea-bed where it can store carbon for thousands or millions of ... read more







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