Experts drill Arctic ice to fathom speed of melt

Wed Sep 7, 2011 9:57am EDT
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By Gerard Wynn and Stuart McDill

500 MILES OFF THE NORTH POLE (Reuters) - As polar bears stalked their ship, scientists drilled into the Arctic sea ice this week to try and figure out why it's disappearing so fast.

The disintegrating ice floes -- each half the size of a football field -- floated among narrow lanes of open water next to the Arctic Sunrise, the Greenpeace ice breaker likely to be the most northerly ship in the world, according to ice pilot Arne Sorensen.

Nearby, in a monochrome landscape between the Norwegian island of Svalbard and the North Pole, a large cub patted and licked a lollipop-shaped part of laser scanner as it passed. Cracks several meters wide appeared in seconds beneath the scientists' feet, prompting a hasty retreat.

Changes in the Arctic are being driven both by manmade greenhouse gases and natural weather patterns. With less ice, less sunlight is reflected back into space, warming the air and melting more ice.

Experts say thinning of ice over recent decades may hasten an ice-free summer as soon as 2020. And, while thickness is more difficult to measure by satellite than area, if anything it is more important.

That has put the onus on better data, through new satellite, plane and submarine observations and a low-tech approach on the ice itself -- drilling holes and poking a tape measure down.

"What the radar of the satellite sees is just the part of the ice that is really above the water and since about nine tenths of the ice is underneath the water there is a huge uncertainty in what the satellite can actually see," said Cambridge University PhD student Till Wagner told Reuters.

"That's what we are here for to get a better handle on how thick the ice actually is," he said, standing on a floe next to the Arctic Sunrise.   Continued...

<p>Nick Toberg, part of a team of scientists from Cambridge trying to find out why Arctic sea ice is melting so fast, conducts survey work on ice floe 500 miles (800 km) from the North Pole September 3, 2011. Arctic sea ice extent is expected to reach one of the lowest levels recorded by satellite since 1979, the head of the main monitoring station told Reuters. This means the five biggest summer melts will have all occurred in the past five years. Picture taken September 3, 2011. REUTERS/Stuart McDill</p>