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Old 07-07-2008, 01:50 AM
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Originally Posted by Kirk View Post
North Pole could be ice-free this summer, scientists say

By Alan Duke
CNN

(CNN) -- The North Pole may be briefly ice-free by September as global warming melts away Arctic sea ice, according to scientists from the National Snow and Ice Data Center in Boulder, Colorado.


Scientists say it's a 50-50 bet that the thin Arctic sea ice will completely melt away at the geographic North Pole.

"We kind of have an informal betting pool going around in our center and that betting pool is 'does the North Pole melt out this summer?' and it may well," said the center's senior research scientist Mark Serreze.

It's a 50-50 bet that the thin Arctic sea ice, which was frozen last autumn, will completely melt away at the geographic North Pole, Serreze said.

The ice retreated to a record level in September when the Northwest Passage -- the sea route through the Arctic Ocean -- opened up briefly for the first time in recorded history.

"What we've seen through the past few decades is the Arctic sea ice cover is becoming thinner and thinner as the system warms up," Serreze said.

Specific weather patterns will determine whether the North Pole's ice cover melts completely this summer, he said.

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"Last year, we had sort of a perfect weather pattern to get rid of ice to open up that Northwest Passage," Serreze said. "This year, a different pattern can set up so maybe we'll preserve some ice there. We're in a wait-and-see mode right now. We'll see what happens."

The brief lack of ice at the top of the globe will not bring any immediate consequences, he said.

"From the viewpoint of the science, the North Pole is just another point in the globe, but it does have this symbolic meaning," Serreze said. "There's supposed to be ice at the North Pole. The fact that we may not have any by the end of this summer could be quite a symbolic change."

Serreze said it's "just another indicator of the disappearing Arctic sea ice cover" but that it is happening so soon is "just astounding to me."

"Five years ago, to think that we'd even be talking about the possibility of the North Pole melting out in the summer, I would have never thought it," he said.

The melting, however, has been long seen as inevitable, he said.

"If you talked to me or other scientists just a few years ago, we were saying that we might lose all or most of the summer sea ice cover by anywhere from 2050 to 2100," Serreze said. "Then, recently, we kind of revised those estimates, maybe as early as 2030. Now, there's people out there saying it might be even before that. So, things are happening pretty quick up there."

Serreze said those who suggest the Arctic meltdown is just part of a historic cycle are wrong.

"It's not cyclical at this point. I think we understand the physics behind this pretty well," he said. "We've known for at least 30 years, from our earliest climate models, that it's the Arctic where we'd see the first signs of global warming.

"It's a situation where we hate to say we told you so, but we told you so," he said.

Serreze said the Arctic sea ice will not be the same for decades.

"If we had a few cold years in a row, we could put sort of a temporary damper on it, but I think at this point going to an ice-free Arctic Ocean is inevitable," he said. "I don't think we can stop that now."

Reduced greenhouse gas emissions could "cool things down a bit," he said.

"It would recover fairly quickly, but it's just not going to happen for a while," he said. "I think we're committed at this point."

There are some positive aspects to the ice melting, he said. Ships could use the Northwest Passage to save time and energy by no longer having to travel through the Panama Canal or around Cape Horn.

"There's also, or course, oil at the bottom of the Arctic Ocean," he said. "Now, the irony of that is kind of clear but the fact that we are opening up the Arctic Ocean does make it more accessible."
Just last Monday, NASA was quietly issuing a press release explaining why Arctic sea ice loss was so great this year. (h/t Douglas Hoyt).

From the release: A team led by Son Nghiem of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., studied trends in Arctic perennial ice cover by combining data from NASA’s Quick Scatterometer (QuikScat) satellite with a computing model based on observations of sea ice drift from the International Arctic Buoy Programme. QuikScat can identify and map different classes of sea ice, including older, thicker perennial ice and younger, thinner seasonal ice.

“Unusual atmospheric conditions set up wind patterns that compressed the sea ice, loaded it into the Transpolar Drift Stream and then sped its flow out of the Arctic,” said Son Nghiem of NASA’s Jet Propulsion Laboratory and leader of the study. When that sea ice reached lower latitudes, it rapidly melted in the warmer waters.

In simpler terms, polar wind patterns changed and blew sea ice further south to warmer waters than it normally would. Sea ice can easily be wind driven.

I wonder if that’s the same mechanism that caused loss of Arctic sea ice in the 1920-30’s?

The Arctic is almost as warm now as it was seventy years ago. Unsurprisingly, Arctic ice has diminished. But, as Polyakov et al.show, the long-term changes are “generally statistically insignificant”. But there’s more ice in Antarctica now. It seems that points more to a natural, cyclical variation on a global scale when one pole diminishes while another gains.

According to Cryosphere Today, normal North Pole ice area at this time is about 5 million km^2, with current amounts amounting to a negative anomaly of about 2 million km^2, for a current total of about 3 million km^2. On the other hand, the South Pole normal area is about 15 million km^2, with current amounts amounting to a positive anomaly of 1 million km^2, for a current total of about 16 million km^2.

Now, it is easy to get alarmed about the North Pole numbers, because they have gotten so close to zero. But the truth is about 2/3rd of total North Pole ice always melts by the end of the northern summer. This summer it got down to about 1/4 of the winter amount.

It is much less alarming if you consider the total between the 2 poles. Using the Cryosphere Today normals and current ice areas, there is normally about 20 million km^2, and currently there is only 19 million km^2. When you realize that the total taken together only represents about a 5% reduction from normal, then it does not seem nearly as alarming.

Arctic = 3 million square kilometers - shrinking, new record low
Antarctic = 16 million square kilometers - growing, new record high
It appears that there is precedence for what we are observing today, and a strong suggestion of a cyclical nature that points to a natural variability mechanism. Plus, the most important thing to note is that we only have satellite measured sea ice data from about 1979. A 30 year trend isn’t enough to conclude much upon, especially when there is clear evidence of a larger period cycle.

Arctic Sea ice loss - “it’s the wind” says NASA Watts Up With That?
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