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Disappearing ice disturbs scientists

Science Matters

David Suzuki
Monday April 24, 2006

Tillsonburg News — Climate change just won't go away, will it? Like a bad penny, it just keeps turning up.

That shouldn't be surprising, since it's a problem of our own making. But what is surprising is that scientists continue to be perplexed at actual observed changes on the planet - changes that seem to be happening much more quickly than expected.

Take ice, for example. It's disappearing. No big surprise, given warming trends over the past several decades. But ice is proving to be more sensitive to temperature change than scientists predicted. Some of the world's largest ice sheets are now on the move and it could mean dramatic rises in sea level over the next 100 years.

While much of the Canadian news about disappearing ice has centred on the Arctic ice pack in the Far North, that ice is already in the water. Its melting will not affect sea levels. Only ice melting off land can do that,
and recent studies show two of the biggest land-based ice sheets, Antarctica and Greenland, are indeed melting.

In Greenland, one study looked at glacial earthquakes associated with glacial flow. It found that seismic activity increased somewhat in the late 1990s, but by 2002 "icequakes" were becoming increasingly common. Last year, Greenland had as many of these events as the combined total between 1993 and 1996.

And the ice isn't just shaking - it's moving. Studies have also found that Greenland's glaciers, which naturally creep along at a glacial pace, have in some cases more than doubled in speed. Just five years ago, the Kangerdlugssuaq Glacier marched into the ocean at a rate of six kilometres a year. In 2005, it moved more than 13 kilometres, sending vast amounts of fresh water and giant icebergs into the sea.

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