Friday, September 16, 2005

Artic Ice melt may have passed the "point of no return."

Scientists have recorded a record loss of sea ice in the Arctic this summer. Many now fear that the Arctic has entered an irreversible phase of warming which will accelerate the loss of polar ice that has helped to keep the climate stable for thousands of years.

Satellites monitoring the Arctic have found that the extent of the sea ice this August has reached its lowest monthly point on record, dipping an unprecedented 18.2 per cent below the long-term average. Scientists believe that this level of ice loss has not happened in hundreds or perhaps thousands of years.

Mark Serreze, one of the scientists at the Snow and Ice Data Centre who monitor Arctic sea ice, says;

This will be four Septembers in a row that we've seen a downward trend. The feeling is we are reaching a tipping point or threshold beyond which sea ice will not recover.

Sea ice reflects up to 80 per cent of sunlight hitting it but this "albedo effect" is mostly lost when the sea is uncovered. "We've exposed all this dark ocean to the sun's heat so that the overall heat content increases," he explained.

Current computer models suggest that the Arctic will be entirely ice-free during summer by the year 2070 but some scientists now believe that even this dire prediction may be over-optimistic, said Professor Peter Wadhams, an Arctic ice specialist at Cambridge University.

When the ice becomes so thin it breaks up mechanically rather than thermodynamically. So these predictions may well be on the over-optimistic side.

Drastic changes in global weather patterns will have a dramatic impact on the limits of what is sustainable human development. We face a problem that extends far beyond renewable energy or reliable water sources. The variables involved are wild and unpredictable.


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