Greenland ice sheet is safer than scientists previously thought
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."
Interesting little factoid:
ReplyDeleteSea levels, today, are below (by just a couple of millimeters) where they were in 2006.
Al Gore, call your office!
ReplyDeleteOh, wait, his office is under 48 inches of snow.
In the 70s Time and Newsweek sold magazines scaring people about the coming Ice Age. In the Aughties they sold magazines scaring people about melting ice caps. In the Twenties they'll sell magazines scaring people about the Ice Age again. Only one thing will not change: it will be the fault of free markets.
The Benny Hill theme is the ultimate crazy car chase music.
ReplyDeleteThat's a Hell of a lot of H2o, ain't it?!
ReplyDeleteLarge areas of Antarctica are growing, mostly on land, I tink.
...Who are the sowers of discord in our time? They are the people who divide what was meant to be united, the people who turn marriage, the fundamental institution of human society, into a battleground over homosexual "marriage"; the people who bring millions of unassimilable immigrants into a once harmonious country and thus divide that country forever; the people who accuse all Republicans and conservatives of being accessories to murder simply for being Republicans and conservatives; the people who call white Americans guilty racists just for existing; the people who have turned our country against itself.
ReplyDeleteAnd who is the greatest sower of discord in Dante's Hell? It is none other than Muhammad (spelled Mahomet in Ciardi's traditional spelling), who, as I have often observed, was the greatest hater and generator of hatred in history, the "successful Hitler," teaching Moslems for the last 1,400 years that all non-Moslems are perverse enemies of Allah who deserve to be killed for the crime of not believing in Allah and his Prophet; the man who launched a war of Moslems against all of non-Moslem humanity that cannot end so long as Islam exists. Dante makes Mahomet the representative denizen of the ninth ditch of the Eighth Circle, where the sowers of discord reside, and has him deliver a speech describing the punishments there. In the medieval view, Islam was not a different religion, but a Christian heresy...
Muhammad in Hell
Via Gerard at American Digest
ReplyDeleteCairo, Egypt (CNN) -- Egyptian Nobel prize laureate and opposition leader Mohamed ElBaradei is Thursday returning to the country, which has been convulsed by unprecedented protests for the past two days, his brother told CNN.
ReplyDeleteElBaradei will participate in protests himself on Friday, his brother Ali said.
...
ElBaradei, the former head of the United Nations nuclear watchdog agency, has been posting messages of support for the demonstrators on Twitter.
The Muslim Brotherhood has called for its followers to demonstrate after Friday prayers -- the first time in the current round of unrest that the largest opposition bloc has told supporters to go out onto the streets.
ReplyDelete...
Security forces cracked down hard on protests Tuesday and Wednesday.
Police turned water cannons and tear gas on protesters in the early hours of Wednesday morning to try to break up anti-government demonstrations as the Interior Ministry warned it "will not allow any provocative movement or a protest or rallies or demonstrations."
In the heart of Cairo, people were being beaten with sticks and fists and demonstrators were being dragged away amid tear gas. Witnesses saw security forces harassing journalists and photographers. Demonstrations continued into the nighttime hours.
Egypt's official MENA news agency reported that at least 90 people were detained Wednesday while trying to demonstrate in downtown Cairo's Tahrir Square.
Some 95% of protesters detained over the last few days will be released on Thursday, the Interior Ministry said. It did not say why the remaining 5% would remain in custody.
Most of the demonstrators were not arrested or charged, the ministry said.
Alexandria, Egypt (CNN) -- Tunisia has brought a blast of reality to Mideast politics. Aging autocrats have been put on notice they can no longer count on docile citizens.
ReplyDeleteBut is an era of unrest approaching? Will the winds of change sweep east along the Maghreb and bring down regimes from North Africa to the Levant and even the Arabian Peninsula?
Beyond doubt, those winds are blowing. Across the region they are being driven by the same social and economic factors, including high unemployment, a booming birth rate, and exploding food prices.
According to the International Monetary Fund, if chronic unemployment and the social tensions that accompany it are to be avoided the Middle East needs to create another 18 million jobs in the next 10 years. From where they stand today that's a very tall order indeed.
Amre Moussa, the Arab League secretary-general and former Egyptian foreign minister, warned regional leaders last week:
"It is on everybody's mind that the Arab spirit is broken. The Arab spirit is down by poverty, unemployment and the general decline in the real indicators of development."