1/26/11, "Greenland ice sheet is safer than scientists previously thought," UK Guardian, Damian Carrington
"New study overturns fears that increased melting could lubricate the ice sheet, causing it to sink ever faster into the sea."
"The threat of the Greenland ice sheet slipping ever faster into the sea because of warmer summers has been ruled out by a scientific study.
Until now, it was thought that increased melting could lubricate the ice sheet, causing it to sink ever faster into the sea. The issue was a key unknown in the landmark 2007 report from the Intergovernmental Panel on Climate Change, which pinned the blame for climate change firmly on greenhouse gas emissions from human activities.
However, the impact of rising sea temperatures on melting ice sheets is still uncertain, meaning it remains difficult to put an upper limit on potential sea level rises. Understanding the risk is crucial because about 70% of the world's population live in coastal regions, which host many of the world's biggest cities, such as London, New York and Bangkok.
"The Greenland ice sheet is safer than we thought," said Professor Andrew Shepherd of the University of Leeds, who led the research published tomorrow in Nature.
Shepherd's team used satellite imagery to track the progress of the west Greenland ice sheet as it slipped towards the sea each summer, over five years.
Researchers had feared that more melting from the surface of the ice in hotter years would in turn provide more meltwater for a slippery film at the sheet's base. More melting would mean more slippage and a greater rise in the sea level.
But they discovered that, above a certain threshold, the slipping began to slow. On-the-ground studies and work done on alpine glaciers suggest that higher volumes of meltwater form distinct channels under the ice, draining the water more efficiently and reducing the formation of a lubricating film.
The Greenland ice sheet studied by Shepherd's team is up to 1,000m (3,280ft) thick. If the entire ice sheet melted, sea levels would rise by a catastrophic seven metres, but this is likely to take 3,000 years if warm air blowing over the ice is the only way in which the ice melts.
Shepherd said most of the Greenland ice cap was on land and not in contact with the sea, unlike the west Antarctic ice sheet. That ice sheet contains enough water to push up sea level by six metres if it all melted.
He said the next scientific question to answer was whether warmer oceans would erode the edges of ice caps, causing them to fall rapidly into the ocean. "The real threat now is from the oceans melting the west Antarctic ice sheet, which is 3km-4km thick, of which 1km-2km is below sea level."
Shepherd said his work was helping to reduce uncertainties about the consequences of climate change. Asked if he thought his work suggested the wider risks of global warming could be discounted, he said: "Not at all.""
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Professor Shepherd is "a contributing author of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change."
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"A simple model of basal lubrication alone misses key aspects of the ice sheet’s response to climate warming."
1/27/11, "Melt-induced speed-up of Greenland ice sheet offset by efficient subglacial drainage," Nature, Aud Venke Sundal, Andrew Shepherd, Peter Nienow, Edward Hanna, Steven Palmer & Philippe Huybrechts
"Fluctuations in surface melting are known to affect the speed of glaciers and ice sheets1, 2, 3, 4, 5, 6, 7, but their impact on the Greenland ice sheet in a warming climate remains uncertain8. Although some studies suggest that greater melting produces greater ice-sheet acceleration7, 9, others have identified a long-term decrease in Greenland’s flow despite increased melting3. Here we use satellite observations of ice motion recorded in a land-terminating sector of southwest Greenland to investigate the manner in which ice flow develops during years of markedly different melting. Although peak rates of ice speed-up are positively correlated with the degree of melting, mean summer flow rates are not, because glacier slowdown occurs, on average, when a critical run-off threshold of about 1.4 centimetres a day is exceeded. In contrast to the first half of summer, when flow is similar in all years, speed-up during the latter half is 62 ± 16 per cent less in warmer years. Consequently, in warmer years, the period of fast ice flow is three times shorter and, overall, summer ice flow is slower. This behaviour is at odds with that expected from basal lubrication alone7, 9. Instead, it mirrors that of mountain glaciers10, 11, 12, where melt-induced acceleration of flow ceases during years of high melting once subglacial drainage becomes efficient. A model of ice-sheet flow that captures switching between cavity and channel drainage modes13 is consistent with the run-off threshold, fast-flow periods, and later-summer speeds we have observed. Simulations of the Greenland ice-sheet flow under climate warming scenarios should account for the dynamic evolution of subglacial drainage; a simple model of basal lubrication alone misses key aspects of the ice sheet’s response to climate warming."
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On July 5, 2005 lead UN climate scientist Phil Jones said "the scientific community" would come down on him if he said there was no warming:
ClimateGate emails, July 5, 2005, from Nobel winner Phil Jones, head of CRU:
Phil Jones: "The scientific community would come down on me in no uncertain terms if I said the world had cooled from 1998.
- OK it has
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Jones says no warming in past 15 yrs.:
2/14/10, "ClimateGate U-Turn as scientist at centre of row admits: there has been no global warming since 1995," UK Daily Mail, J. Petre
- "He (Phil Jones) further admitted that in the last 15 years there had been no ‘statistically significant’ warming,
- although he argued this was a blip rather than the long-term trend."...
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Ed. note: At minimum, not a penny more US taxpayer money should be spent on man-caused climate research. At minimum, it is clearly not a life threatening issue. Such has been the excuse to transfer hundreds of billions of precious taxpayer dollars to the trillion dollar 'climate' industry. We have actual problems that have gotten worse because needed revenue was and continues to be transferred to climate profiteers such as Goldman Sachs:
7/02/09, "The Great American Bubble Machine: How Goldman Sachs has Engineered Every Major Market Manipulation Since the Great Depression," Rolling Stone, by Matt Taibbi
"A groundbreaking new commodities bubble,
- called cap-and-trade.
- except it has one delicious new wrinkle:
- will be government-mandated.
- Goldman won't even have to rig the game.
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