Monday, May 12, 2008

Arctic Melt

This recent release gives us the current take on pending sea ice behavior. I am not anticipating a major continuation of last season’s abrupt ice removal. In fact, I think that a small accumulation is much more likely.
But I emphasize small approaching unnoticeable. As of a week ago ice coverage remained above normal in the Western Arctic but remember that it is thinner than usual so will soon disappear at least on schedule.

In the Siberian Arctic, ice removal is ahead of schedule, perhaps reflecting strong wind activity. It is early enough and strong enough to make one think that we have a chance this year for a cleared Eastern sea route this year. There is plenty to watch.

Since the Northern Hemisphere had the close equivalent of a normal cold winter this year, it appears unlikely that there is any available excess of heat to dump into the Arctic this year. So we need expect little beyond a clearing out of last winter’s sea ice.

In the mean while, since 1980, the sea ice in the Antarctic has expanded 140 plus percent over 28 years. This again suggests that at least on that the basis of that rough measure alone, that the net global heat equation variation between hemispheres approaches zero.
The challenging question is what switches the poles? I am asking that because of the evidence we have of the little ice age and similar past events of sustained cooling that is best explained by such a switch in the Atlantic.

I am reasonably convinced that left to itself, the Northern Polar region would be a couple degrees warmer matching the apparent temperature regime of the Bronze Age. Perhaps we will find out in a couple of hundred years.

WASHINGTON (Reuters) - Arctic sea ice, sometimes billed as Earth's air conditioner for its moderating effects on world climate, will probably shrink to a record low level this year, scientists predicted on Wednesday.
In releasing the forecast, climate researcher Sheldon Drobot of the University of Colorado at Boulder called the changes in Arctic sea ice "one of the more compelling and obvious signs of climate change."

If that prediction holds true, it would be the third time in the past five years that Arctic sea ice retreated to record lows, the scientists said in a statement. That retreat is caused by warming temperatures and the spread of younger, thinner, less hardy ice in the region.

Based on satellite data and temperature records, the researchers forecast a 59 percent chance the annual minimum sea ice record would be broken again in 2008.

In the past decade, Arctic sea ice declined by roughly 10 percent, with a record drop in 2007 that left a total minimum ice cover of 1.59 million square miles. That represented a decline of 460,000 square miles from the previous record low in 2005 -- an area the size

Three more chunks like that and there is no sea ice at all!

of Texas and California combined. Scientists measure ice cover at its low ebb at the end of summer.

"The current Arctic ice cover is thinner and younger than at any previous time in our recorded history, and this sets the stage for rapid melt and a new record low," Drobot said.

Overall, 63 percent of the Arctic ice cover is younger than average, and only 2 percent is older than average, he said.

If Arctic sea ice keeps melting, it could hurt local wildlife, including polar bears, walruses and seals, the scientists said.

For humans, however, larger areas and longer periods of open Arctic water could make for cheaper merchant shipping between Europe and North America.

Arctic sea ice helps cool the planet with its usually reliable stores of white, sun-reflecting sea ice.

Sea ice melts and refreezes seasonally, but recent years have shown a smaller area of maximum sea ice in the winter, which suggests it is more difficult to restock the supply of polar ice after a record summer melt like last year's.

(Editing by Peter Cooney)

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