Antarctic ice growing despite global warming
gabers
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http://www.newscientist.com/article/dn1 ... rming.html
I've seen a lot of arguments from the "global warming is a lie" crowd that global warming must be a farce since the antarctic ice has been steady or growing. A recent study published in the magazine New Scientist indicates the reason for this.
It's the southern ozone hole whatdunit. That's why Antarctic sea ice is growing while at the other pole, Arctic ice is shrinking at record rates. It seems CFCs and other ozone-depleting chemicals have given the South Pole respite from global warming.
But only temporarily. According to John Turner of the British Antarctic Survey, the effect will last roughly another decade before Antarctic sea ice starts to decline as well.
Arctic sea ice is decreasing dramatically and reached a record low in 2007. But satellite images studied by Turner and his colleagues show that Antarctic sea ice is increasing in every month of the year expect January. "By the end of the century we expect one third of Antarctic sea ice to disappear," says Turner. "So we're trying to understand why it's increasing now, at a time of global warming."
In a new study, Turner and colleagues show how the ozone hole has changed weather patterns around Antarctica. These changes have drawn in warm air over the Antarctic Peninsula in West Antarctica and cooled the air above East Antarctica.
The Southern Ocean is home to some of the strongest ocean winds on the planet. The region between 40° and 60° South is well-known to sailors who call it the "roaring forties" and "furious fifties".
Wind vortex
If the South Pole were smack in the middle of Antarctica, the winds would circle neatly around it in a clockwise direction. But in fact the continent is set slightly off-centre relative to the South Pole. As a result, the winds whip off Victoria Land and create a vortex over the Southern Ocean north of the Ross Sea (see blue area in figure). Turner compares this to the way wind going down a line of buildings will whip into a vortex when it comes to a corner.
The vortex generates a large area of storm activity. It also draws in warm air from South America over the Antarctic Peninsula, making this the warmest region of the continent.
By running an atmospheric computer model with and without the ozone hole, Turner and his colleagues found that the depletion of the ozone has intensified the winds of the roaring forties and furious fifties. The net result has been to draw more warm air in from Chile – which has warmed the Antarctic peninsula and caused the collapse of several ice shelves – and generate stronger cool-air storms around the Ross Sea.
Satellite data shows that sea ice has shrunk west of the Antarctic Peninsula and grown in the Ross Sea. Because the increase in sea ice extent has been greater than the reduction around the Antarctic peninsula the net effect is that since the ozone hole appeared 30 years ago, Antarctic ice has grown. The researchers say their models suggest this is most likely a result of the ozone hole although they cannot rule out the possibility that natural variations in sea ice extent have also played a role.
Ozone healing
"Over the next 50 to 100 years, the ozone hole will heal," says Turner. "At the same time, greenhouse gases will rise. In next decade or so we should see sea ice plateauing and then decreasing massively if greenhouse gases continue to increase."
Earlier this year, research led by Eric Steig of the University of Washington, Seattle showed that although the Antarctic continent as a whole has warmed by 0.5°C in the last 50 years – on a par with the global average – the figure hides strong regional differences. West Antarctica has warmed while temperatures over East Antarctica have dropped.
Accordingly, the disintegration of large ice shelves have all been in West Antarctica, the most famous example being the Larsen ice shelf. More recently, scientists have been anxiously expecting the Wilkins ice shelf to collapse as well.
Journal reference: Geophysical Research Letters (DOI: 10.1029/2009GL037524, in press)
I've seen a lot of arguments from the "global warming is a lie" crowd that global warming must be a farce since the antarctic ice has been steady or growing. A recent study published in the magazine New Scientist indicates the reason for this.
It's the southern ozone hole whatdunit. That's why Antarctic sea ice is growing while at the other pole, Arctic ice is shrinking at record rates. It seems CFCs and other ozone-depleting chemicals have given the South Pole respite from global warming.
But only temporarily. According to John Turner of the British Antarctic Survey, the effect will last roughly another decade before Antarctic sea ice starts to decline as well.
Arctic sea ice is decreasing dramatically and reached a record low in 2007. But satellite images studied by Turner and his colleagues show that Antarctic sea ice is increasing in every month of the year expect January. "By the end of the century we expect one third of Antarctic sea ice to disappear," says Turner. "So we're trying to understand why it's increasing now, at a time of global warming."
In a new study, Turner and colleagues show how the ozone hole has changed weather patterns around Antarctica. These changes have drawn in warm air over the Antarctic Peninsula in West Antarctica and cooled the air above East Antarctica.
The Southern Ocean is home to some of the strongest ocean winds on the planet. The region between 40° and 60° South is well-known to sailors who call it the "roaring forties" and "furious fifties".
Wind vortex
If the South Pole were smack in the middle of Antarctica, the winds would circle neatly around it in a clockwise direction. But in fact the continent is set slightly off-centre relative to the South Pole. As a result, the winds whip off Victoria Land and create a vortex over the Southern Ocean north of the Ross Sea (see blue area in figure). Turner compares this to the way wind going down a line of buildings will whip into a vortex when it comes to a corner.
The vortex generates a large area of storm activity. It also draws in warm air from South America over the Antarctic Peninsula, making this the warmest region of the continent.
By running an atmospheric computer model with and without the ozone hole, Turner and his colleagues found that the depletion of the ozone has intensified the winds of the roaring forties and furious fifties. The net result has been to draw more warm air in from Chile – which has warmed the Antarctic peninsula and caused the collapse of several ice shelves – and generate stronger cool-air storms around the Ross Sea.
Satellite data shows that sea ice has shrunk west of the Antarctic Peninsula and grown in the Ross Sea. Because the increase in sea ice extent has been greater than the reduction around the Antarctic peninsula the net effect is that since the ozone hole appeared 30 years ago, Antarctic ice has grown. The researchers say their models suggest this is most likely a result of the ozone hole although they cannot rule out the possibility that natural variations in sea ice extent have also played a role.
Ozone healing
"Over the next 50 to 100 years, the ozone hole will heal," says Turner. "At the same time, greenhouse gases will rise. In next decade or so we should see sea ice plateauing and then decreasing massively if greenhouse gases continue to increase."
Earlier this year, research led by Eric Steig of the University of Washington, Seattle showed that although the Antarctic continent as a whole has warmed by 0.5°C in the last 50 years – on a par with the global average – the figure hides strong regional differences. West Antarctica has warmed while temperatures over East Antarctica have dropped.
Accordingly, the disintegration of large ice shelves have all been in West Antarctica, the most famous example being the Larsen ice shelf. More recently, scientists have been anxiously expecting the Wilkins ice shelf to collapse as well.
Journal reference: Geophysical Research Letters (DOI: 10.1029/2009GL037524, in press)
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New York City-sized ice collapses off Antarctica
Tue Apr 28, 2009 7:00pm EDT Print This Article | Single Page[-] Text [+]
1 of 1Full SizeBy Alister Doyle, Environment Correspondent
TROMSOE, Norway (Reuters) - An area of an Antarctic ice shelf almost the size of New York City has broken into icebergs this month after the collapse of an ice bridge widely blamed on global warming, a scientist said Tuesday.
"The northern ice front of the Wilkins Ice Shelf has become unstable and the first icebergs have been released," Angelika Humbert, glaciologist at the University of Muenster in Germany, said of European Space Agency satellite images of the shelf.
Humbert told Reuters about 700 sq km (270.3 sq mile) of ice -- bigger than Singapore or Bahrain and almost the size of New York City -- has broken off the Wilkins this month and shattered into a mass of icebergs.
She said 370 sq kms of ice had cracked up in recent days from the Shelf, the latest of about 10 shelves on the Antarctic Peninsula to retreat in a trend linked by the U.N. Climate Panel to global warming.
The new icebergs added to 330 sq kms of ice that broke up earlier this month with the shattering of an ice bridge apparently pinning the Wilkins in place between Charcot island and the Antarctic Peninsula.
Nine other shelves -- ice floating on the sea and linked to the coast -- have receded or collapsed around the Antarctic peninsula in the past 50 years, often abruptly like the Larsen A in 1995 or the Larsen B in 2002.
The trend is widely blamed on climate change caused by heat-trapping gases from burning fossil fuels, according to David Vaughan, a British Antarctic Survey scientist who landed by plane on the Wilkins ice bridge with two Reuters reporters in January.
Humbert said by telephone her estimates were that the Wilkins could lose a total of 800 to 3,000 sq kms of area after the ice bridge shatteredThe Wilkins shelf has already shrunk by about a third from its original 16,000 sq kms when first spotted decades ago, its ice so thick would take at least hundreds of years to form.
Temperatures on the Antarctic Peninsula have warmed by up to 3 Celsius (5.4 Fahrenheit) this century, Vaughan said, a trend climate scientists blame on global warming from burning fossil fuels in cars, factories and power plants.
The loss of ice shelves does not raise sea levels significantly because the ice is floating and already mostly submerged by the ocean.
But the big worry is that their loss will allow ice sheets on land to move faster, adding extra water to the seas.
Wilkins has almost no pent-up glaciers behind it, but ice shelves further south hold back vast volumes of ice.
The Arctic Council, grouping nations with territory in the Arctic, is due to meet in Tromsoe, north Norway, Wednesday to debate the impact of melting ice in the north.
I thought the world...Turns out the world thought me
Did you actually read the article?
environmentalists making money, that almost makes a little bit of sense.
playing politics with the survival of the human race, wonderful.
I understand the fear of big government. But don't you think the "green economy" that Obama is helping stimulate is much better than continuing the abusive relationship with the big oil and big coal folks? Shit, another four years with Bush and Co. and we probably would have been burning all the trees to make charcoal to liquify into fuel. Sometimes you folks need to see the big picture here.
Not all fat people. Just the ones driving 6,000-lb. SUVs that get 12 mpg and eat 20-oz. steaks for dinner every other night. Like say, your typical fat Texan.
Really, if you're going to make a stand in any fashion on global warming it's good to study up a bit. Try to find unbiased sources when possible and develop some sort of basic understanding of science. I'm talking people in general, not specifically you gecko.
does not matter.......the law of conservation will prevail and destroy the earth.
let's see ... on one end of the global warming debate we have oil executives and on the other hand we have second-hand clothes wearing hippies ...
thinking environmentalists are making money on global warming is absurd
And I don't really understand what motivation anyone would have to lie about it..
OK, you realize that NONE of that makes sense, right?
really?
education is a relative thing