Arctic ice melt opens Northwest Passage

NF Reporter · 09-16-2007, 01:46 AM

AP - Arctic ice has shrunk to the lowest level on record, new satellite images show, raising the possibility that the Northwest Passage that eluded famous explorers will become an open shipping lane.

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waltky · 09-25-2007, 02:32 AM

When enough ice melts, there won't be a Florida to be worried about hurricanes...

Two more signals from Arctic sea ice
Sept 24, 2007 - Winter ice declining and ice becoming thinner, adding to summer decline

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The opening of the fabled Northwest Passage and the recent announcement that Arctic Sea ice has reached a new record summer low are just the tip of the iceberg when it comes to polar problems, so to speak. Two new studies by scientists who keep an eye on sea ice melt have provided further evidence that the Arctic is currently suffering the brunt of global warming's effects, with the ice becoming thinner and winter ice also beginning to decline.

Ice melt in the summer is a normal phenomenon: As summer temperatures heat up the Northern Hemisphere, Arctic sea ice begins to melt, and its edge retreats and covers less of the North polar region. When temperatures begin to drop again in the winter, the ice reforms. But in recent years, rising air and ocean temperatures, fueled by global warming, have caused more and more ice to melt each summer, with ice extent reaching a record low on Sept. 16 this year, according to the University of Colorado at Boulder's National Snow and Ice Data Center (NSIDC). Winter sea ice, on the other hand, had remained fairly steady—until now.

Winter decline

A new study examining satellite measurements of the winter sea ice covering the Barents Sea (located north of Scandinavia) over the past 26 years has shown that the ice edge has recently been retreating in the face of rising sea surface temperatures, said study leader Jennifer Francis of Rutgers University. Her research, detailed in a recent issue of the journal Geophysical Research Letters, showed that the warming waters in the Barents Sea — which have risen about 3 degrees Celsius since 1980 — are to blame for the reduction in winter ice cover. Two factors contribute to the warming of the Barents Sea: warming Atlantic waters funneled in by the Gulf Stream and solar heating of the open ocean as ice melts in the summer, both of which make it harder for new ice to form in the winter.

More Two new Arctic sea ice signals - LiveScience - MSNBC.com

waltky · 10-31-2007, 09:13 PM

More land to fight over now...

New land surfaces in Arctic tug-of-war
Wed., Oct. 31, 2007 : Warming, retreating sea ice expose new areas as nations vie for control

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A rocky outcrop found off the northern coast of Greenland could open up a new front in the looming battle for control of the Arctic and the North Pole. The best candidate to date for the world's northernmost point of land — a mythical place sought by explorers for centuries — was spotted in July during an expedition led by Arctic veteran Dennis Schmitt.

California-based Schmitt, best-known for his 2005 discovery of Warming Island off the eastern coast of Greenland, named it Stray Dog West because, he said, it "erred under the ice." It was exposed mainly by shifting pack ice. As Greenland is under Denmark's administration, this scrap of land just 125-feet long could extend Danish territory further north and strengthen Copenhagen's claim on the pole.

Its discovery comes as countries around the Arctic Ocean — the United States, Russia, Canada, Denmark, Norway and Iceland — are rushing to stake out the Polar Basin's seabed, fishing rights and maritime routes. "This little island could have a wide international significance," said Stefan Talmon, professor of international law at Oxford University in Britain. "With the ice melting, more and more of these islands could emerge and play a role in maritime delimitations."

More New land surfaces in Arctic tug-of-war - Climate Change - MSNBC.com

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North Pole trip may be impossible
1 Nov 2007, Trips over ice to the North Pole may be impossible in summer in just a decade or two because of global warming, according to one of the world's leading polar adventurers.

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Norwegian Boerge Ousland, who has skied alone across the Arctic Ocean and the Antarctic, said he would recommend one piece of equipment for anyone planning a trek to the North Pole in a few years' time: a kayak. "It's a bit strange to think that the trips I have been doing may not be possible in 10-20 years," he said after attending a climate seminar in the Norwegian parliament. "But it may well happen."

That would end just over a century of trips across the ice - American Robert Peary was the first to claim to reach the North Pole in 1909. "Over time I have seen the changes myself," said Ousland, aged 45, who has been to the north pole several times. On a first trip in 1990 the ice was about three meters thick around the North Pole. "Now it is 30% thinner," he said.

There were also far more and wider gaps in the ice with open water, requiring risky swims in a special survival suit while tugging provisions and other gear along in a floating sledge. The Arctic ice shrank in September 2007 to the smallest on record, eclipsing a 2005 low, according to US satellite data.

It is now expanding again as winter approaches but many climate scientists say that the ice could vanish in summer well before the end of the century because of a build-up of greenhouse gases, mainly from burning fossil fuels. And the summer ice now starts several hundred kilometers further north than a century ago. Few expeditions can now begin from Russia's Cape Arkticheskiy, as Ousland did in 1990, because a helicopter ride is needed to reach firm ice.

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waltky · 04-18-2008, 01:29 AM

Now ya see it, now ya don't...

Greenland lake disappears under the ice
April 17, 2008 - We tend to think of glacial as a synonym for slow, but summer on an ice sheet can be pretty dynamic.

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Lakes can form on ice sheets as melt water pools during warm summer days. These lakes decrease the albedo of the surface, leading to more melting. Once enough water collects, the pressure it creates can cause a fracture in the underlying (less dense) ice, allowing the lake to drain catastrophically. These events take on added significance due to what happens to that water. If the lake drains to the bottom of the ice sheet, it can lubricate the bed of the ice sheet, and thus increase rates of movement. That movement can lead to an increased flux of water into the ocean, thus raising sea levels.

A report in today's Science describes how researchers recorded the drainage of one such lake in Greenland. The lake was roughly 5.6 km2, but drained completely in less than an hour and a half. The lake's contents rapidly made their way down to the bottom of the ice sheet, 980 m below the surface. During this period, the average drainage rate was 8700 m3/s. For reference, the average flow rate for Niagara Falls is only 5700 m3/s. In the 16 hours prior to the catastrophic drainage, they noted a slow decrease in water level. They suggest that this corresponds to the slow initial fracturing of the ice. During this period, the lake was only filling the fracture it was creating. Once this fracture reached the base, the researchers believe that the water spread out in an existing subglacial network, which facilitated the rapid lake drainage.

Along with this drainage, the team recorded movement of the ice sheet (both vertically and horizontally), along with a corresponding increase in glacial seismic activity. As the lake drained, the ice sheet was temporarily lifted by a meter. As the water spread out at the base of the ice sheet, the surface elevation slowly decreased back to its initial level over the course of 24 hours. Along with this lifting came a very rapid shift north of almost one meter, followed by a slow drift back south and movement west of less than one meter. The fracture created by this lake remained on the surface as a conduit for future melt water. The team also noted that other post-drainage lake beds they came across exhibited the same type of fractures, suggesting that the process they recorded is quite common. Indeed, thousands of lakes are formed each summer season, and they must go somewhere.

A related study also published in Science today looked at the change in ice movement related to basal lubrication. The study found that, while the water lubricating the base of the ice sheet caused seasonal speedups of its motion on the order of 50 to 100 percent, the speedup of outlet glaciers, where the ice sheet drains into the ocean, was only about 15 percent. While other factors are causing outlet glaciers to speed up, lubrication of the base doesn't seem to be the main cause.

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