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Title: Huge ice sheet breaks from Greenland glacier
Source:
BBC
URL Source: http://www.bbc.co.uk/news/science-environment-10900235
Published: Aug 7, 2010
Author: staff
Post Date: 2010-08-07 11:30:09 by buckeroo
Keywords: None
Views: 772
Comments: 37
A giant sheet of ice measuring 260 sq km (100 sq miles) has broken off a glacier in Greenland, according to researchers at a US university. The block of ice separated from the Petermann Glacier, on the north-west coast of Greenland. It is the largest Arctic iceberg to calve since 1962, said Prof Andreas Muenchow of the University of Delaware. The ice could become frozen in place over winter or escape into the waters between Greenland and Canada. Related stories If the iceberg moves south, it could interfere with shipping, Prof Muenchow said. Cracks in the Petermann Glacier had been observed last year and it was expected that an iceberg would calve from it soon. The glacier is 1,000 km (620 miles) south of the North Pole. Graphic A researcher at the Canadian Ice Service detected the calving from Nasa satellite images taken early on Thursday, the professor said. The images showed that Petermann Glacier lost about one-quarter of its 70km-long (43-mile) floating ice shelf. There was enough fresh water locked up in the ice island to "keep all US public tap water flowing for 120 days," said Prof Muenchow. He said it was not clear if the event was due to global warming. The first six months of 2010 have been the hottest on record globally, scientists have said. Thousands of icebergs calve off Greenland's glaciers annually, but they are seldom so large.
Poster Comment: Incredible.
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#4. To: buckeroo, *Agriculture-Environment* (#0)
Far from being proof of AGW, actually is more in keeping with glacier growth.
I don't agree. I think these various apparent and isolated snapshots across the world is proof about global warming phenomena. Now, the exact cause is uncertain. But, there is no question about man-made interference as one of the contributors.
glaciers calving is not from melting, that would be glacier retreating. Glaciers calve when they grow.
#8. To: farmfriend (#6)
I couldn't have said it better!
Well, but like I've said before, nothing trumps reality like political correctness. Let it go. Just resign yourself to the "fact" that the white debbils is causing global warming. And like Loddy said earlier today: Pay up sucker!
WHOOPS! Weird science, 'eh? "While there have been ice breakouts of this magnitude from Jakonbshavn and other glaciers in the past, this event is unusual because it occurs on the heels of a warm winter that saw no sea ice form in the surrounding bay. While the exact relationship between these events is being determined, it lends credence to the theory that warming of the oceans is responsible for the ice loss observed throughout Greenland and Antarctica." The observation was of the northern part of the westerly-located Jakobshavn Isbrae glacier. NASA said this glacier has been slowly melting over the past 160 years, losing 27 miles of ice. However, the melting has accelerated with six miles of ice lost in the past decade alone. The ice loss has effectively separated the glacier into two sections - north and south. NASA said the loss of ice in Greenland is "... believed to be the single largest contributor to sea level rise in the northern hemisphere." This calving of ice was the first time NASA scientists were able to see the event occur almost in real time, and because satellite image capture has improved, allowed the scientists to see details of the event not previously available. Images from three different satellites provided NASA with the observations of the calving event. Earlier this year, NASA said Greenland's glaciers were "... melting 100 times faster at their end points beneath the ocean than they are at their surfaces... The results suggest this undersea melting caused by warmer ocean waters is playing an important, if not dominant, role in the current evolution of Greenland's glaciers, a factor that had previously been overlooked." Greenland.com said some of the ice in Greenland's glaciers is thought to be up to 100,000 years old. "The ice contains 10 per cent of the world’s reserves of fresh water as well as atmospheric particles which scientists can use to gain an insight into the climate of both Greenland and the Earth going back some 250,000 years. Greenland’s ice sheet is melting today far more rapidly than at the turn of the millennium. Many researchers think that every year the ice is losing more mass than is being created. If the entire ice sheet melted, the world’s oceans would rise by approx. 6-7 metres (20-23 feet)." One of the latest studies, published this week, shows the level of water in the Indian Ocean is increasing. The researchers found there has been an increase of half an inch of water each decade, which they attribute to human-caused global warming. The researchers said in a press release "Our new results show that human-caused changes of atmospheric and oceanic circulation over the Indian Ocean region -- which have not been studied previously -- are the major cause for the regional variability of sea level change." There is an upside to the melting of Greenland's glaciers. Entrepreneurs are bottling up water collected from the melting glaciers, which it is exporting to water-thirsty Dubai, reported the Copenhagen Post. With interest from buyers in Japan, Singapore and the USA, Iluliaq Original Water takes capitalization on global warming to an entirely new level. The water is said to be some of the purest in the world, but the exclusive product will not be readily available to the masses.
Whoops!
WHOOPS! February 16, 2010 Researchers Eric Rignot and Isabella Velicogna, both of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the University of California, Irvine; along with colleague Michele Koppes of the University of British Columbia, Vancouver, Canada, measured the undersea melting rates of four glaciers in central west Greenland in the summer of 2008. They deployed oceanographic equipment in the glacier fjords, sampling the water at various depths to measure ocean currents, temperature and salinity, along with the depth of the fjords. The researchers found the melt rates of the glaciers studied was 100 times larger under the ocean at their terminus points than that observed at the glacial surfaces. Rignot said the new study complements other recent research on the effects of ocean conditions in Greenland fjords. A study in the same online issue of Nature Geoscience by researcher Fiammetta Straneo of the Woods Hole Oceanographic Institution, Woods Hole, Mass., and colleagues looked at changes in oceanographic conditions in fjords that may be conducive to changes in undersea melting. Another 2008 Nature Geoscience study by researcher David Holland of New York University, New York, found that Greenland glaciers sped up as warm waters intruded into their fjords. "Our study fills the gap by actually looking at these submarine melt rates, something that had never been done before in Greenland," Rignot said. "The results indicate rather large values that have vast implications for the evolution of the glaciers if ocean waters within these fjords continue to warm." In recent years, scientists have observed a widespread acceleration of Greenland's glaciers, associated with thinning of their lower reaches as they reach the sea. In the past decade, surface melting of glaciers around Greenland due to warm air temperatures has increased in both magnitude and area, while snowfall has increased just slightly. The result is a tripling in the amount of ice mass lost in Greenland between 1996 and 2007. Of this loss, between 50 and 60 percent is attributable to a speedup in the flow of outlet glaciers, with the remainder due to increased surface melting. But the glaciers also melt along their submerged faces, where they come into contact with warm ocean waters. A warmer ocean erodes a glacier's submerged, grounded ice and causes its grounding line -- the point at which a tidewater glacier floats free of its bed -- to retreat. Little is known about these rates of undersea melting and how they may influence the glaciers. The only previous measurements of undersea glacier melting were in Alaska. The melting of glaciers beneath the ocean surface causes deep, warm, salty water to be drawn up toward the glacier's face, where it mixes turbulently with the glacier's cold, fresh water. The water then rises along the glacier face, melting its ice along the way, then reaches the ocean surface and flows away from the glacier in a plume. An ocean temperature of 3 degrees Celsius (37.4 degrees Fahrenheit) can melt glacial ice at a rate of several meters per day, or hundreds of meters over the course of a summer. Rignot said the study points to the need to include the ocean factor if scientists are to increase the reliability of models used to predict how Greenland will be affected by climate change. "All major Greenland glaciers end up in the ocean, and tidewater glaciers control 90 percent of the ice discharged by Greenland into the sea," Rignot said. "Submarine melting may therefore have a large indirect impact on the ice mass budget of the entire Greenland Ice Sheet. If we are to determine the future of the Greenland Ice Sheet more reliably in a changing climate, more complete and detailed studies of the interactions between ice and ocean at the ice sheet's margins are essential." Alan Buis
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#5. To: farmfriend (#4)
Far from being proof of AGW ...
#6. To: buckeroo (#5)
Replies to Comment # 6. glaciers calving is not from melting, that would be glacier retreating. Glaciers calve when they grow.
#9. To: farmfriend, Lod (#6)
#10. To: farmfriend (#6)
glaciers calving is not from melting, that would be glacier retreating. Glaciers calve when they grow.
NASA: Greenland glacier retreated 1 mile in 24 hours By Stephanie Dearing.
NASA reported last week that a massive chunk of Greenland glacial ice was lost as it broke up and fell into the ocean. The loss of the ice meant the glacier retreated one mile overnight. Satellite imagery showed a chunk of ice about 2.7 square miles calving from a Greenland glacier. The ice lost is approximately 1/8 the size of Manhattan Island. The calving caused the "calving front" of the glacier to retreat one mile overnight. The amount of ice lost was not as important as were the conditions noted NASA scientist, Thomas Wagner.
#11. To: farmfriend (#6)
glaciers calving is not from melting, that would be glacier retreating. Glaciers calve when they grow.
Jakobshavn Glacier Calving Front Recession from 1851 to 2009
Jakobshavn Isbrae is located on the west coast of Greenland at Latitude 69 N. The ice front, where the glacier calves into the sea, Between 1850 and 1964 the ice front retreated at a steady rate of about 0.3 km/yr, after which it occupied approximately the same location until 2001, when the ice front began to recede again, but far more rapidly at about 3 km/yr. As more ice moves from glaciers on land into the ocean, it causes a rise in sea level. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining 6.5 percent of Greenland's ice sheet area. The ice stream's speed-up and near-doubling of the ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase.
#13. To: farmfriend (#6)
glaciers calving is not from melting, that would be glacier retreating. Glaciers calve when they grow.
NASA Finds Warmer Ocean Speeding Greenland Glacier Melt
Glaciers in west Greenland are melting 100 times faster at their end points beneath the ocean than they are at their surfaces, according to a new NASA/university study published online Feb. 14 in Nature Geoscience. The results suggest this undersea melting caused by warmer ocean waters is playing an important, if not dominant, role in the current evolution of Greenland's glaciers, a factor that had previously been overlooked.
818-354-0880
alan.buis@jpl.nasa.gov
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