Perilous
Times and Climate Change
Rapidly Melting ice on Arctic islands boosts sea levels:
study
by Staff Writers
Paris (AFP) April 21, 2011
Melting glaciers and ice caps on Canadian Arctic islands play a
far greater role in sea level rise that previously suspected,
according to a study published Thursday.
Between 2004 and 2009, the 30,000 snow-and-ice covered islands in
the Canadian Archipelago shed 363 cubic kilometres (87 cubic
miles) of water, equivalent to three-quarters of contents of Lake
Erie, the study found.
During the first half of this six-year period, the average loss
was 29 cubic kilometres (seven cubic miles) per year. But during
the second three-year period, the average jumped to 92 cubic
kilometres (22 cubic miles) annually.
Over the full six years, this added a total of one millimeter to
the height of the worlds oceans, the researchers calculated.
"This is a region that we previously didn't think was contributing
to sea level rise," said Alex Gardner, a researcher at the
University of Michigan and lead author of the study.
"Now we realise that outside of Antarctica and Greenland, it was
the largest contributor for the years 2007 through 2009. This area
is highly sensitive and if temperatures continue to increase, we
will see much more melting," he said in a statement.
Ninety-nine percent of all the world's land ice is trapped in the
massive ice sheets of Antarctica and Greenland.
Despite their size, however, they currently only account for about
half of the land-ice bleeding each year into the oceans, mainly
because they are so thick and cold that ice melts only at their
edges.
The other half of the ice melt contributing to sea-level rise
comes from smaller mountain glaciers and ice caps such as those in
the Canadian Arctic, Alaska and Patagonia.
The study's results, published in Nature, show that the impact of
these regions on sea level rise has been largely overlooked.
Gardner cautioned that the relatively short time span of the study
-- six years -- is not long enough to constitute a climate trend,
but said the results should be taken as a warning.
"This is a big response to a small change in climate," he said.
"If the warming continues and we start to see similar responses in
other glaciated regions, I would say it's worrisome."
Most experts on climate change and sea levels project that the
ocean watermark will rise roughly a metre by century's end.
This could be devastating for tens of millions of people living in
low-lying deltas, many of which are also sinking at the same time.
Rising sea levels could poison aquifers and amplify the impacts of
storm surges and tsunamis, experts say.