Shockwaves
From Melting Icecaps
Are Triggering Earthquakes
By Daniel Howden,
in Ilulissat, Greenland
08 September, 2007
The
Independent
High
up inside the Arctic circle the melting of Greenland's ice sheet has
accelerated so dramatically that it is triggering earthquakes for the
first time.
Scientists monitoring the
glaciers have revealed that movements of gigantic pieces of ice are
creating shockwaves that register up to three on the Richter scale.
The speed of the arctic ice
melt has accelerated to such an extent that a UN report issued earlier
this year is now thought to be out of date by its own authors.
The American polar expert
Robert Correll, among the key contributors to the UN International Panel
on Climate Change (IPCC) report issued in February, described the acceleration
as "massive".
Estimates of the likely rise
in sea levels this century vary, and the IPCC published a conservative
range of between 20cm-60cm. But those estimates are now heavily disputed,
with many scientists insisting that new data collected since the IPCC
report suggested a rise closer to two metres. Professor Correll said
there was now a "consensus" that a significant acceleration
in the loss of ice mass has occurred since the last report.
The revelations came at a
conference in the north of Greenland, which has drawn world religious
leaders, scientists and environmentalists to the Ilulissat Icefjord.
Ilulissat is home to the most active glacier in Greenland and it was
one of the immense icebergs that calve from it on a daily basis that
is believed to have sunk the Titanic. The Arctic is acknowledged as
the fastest warming place on earth.
The local Inuit population,
whose lives have been drastically altered by the changing climate, were
yesterday led in a silent prayer for the future of the planet by the
Ecumenical Patriarch Bartholomew, the organiser of the arctic symposium
and spiritual leader of the world's 250 million Orthodox Christians.
Greenland's ice cap is immense,
the second largest in the world, and its break-up would be catastrophic.
The packed ice is up to two miles thick and its total collapse into
the ocean would raise worldside sea levels by seven metres.
At the Ilulissat Icefjord,
250km north of the Arctic Circle, the advance of the glacier into the
sea is now visible to the naked eye. "It's moving toward the sea
at a rate of two metres an hour," said Professor Correll. "It's
exuding like toothpaste, moving towards us at 15 kilometres per year."
One day's worth of the Ilulissat
ice would provide enough fresh water to supply the largest cities in
the world for a whole year – and yet it amounts to only 7 per
cent of Greenland's total melt.
As the glaciers thaw, pools
of water are forming, feeding fractures in the ice, down which the water
flows until it hits the bedrock.
"These so-called moulins
are phenomenal," said Professor Correll, who said they had been
remarkably scarce when he first visited the glacier in 1968. "Now
they are like rivers 10 or 15 metres in diameter and there are thousands
of them."
He compared the process to
putting oil underneath the ice to make it move forward faster.
As the reality of the unprecedented
thaw becomes apparent, the consequences are outstripping the capacity
of scientific models to predict it.
Earthquakes, or glacial ice
quakes, in the north-west of Greenland are among the latest ominous
signs that an unprecedented step change is under way. The Finnish scientist
Veli Albert Kallio is one of the region's leading ice experts and has
been tracking the earthquakes.
"Glacial earthquakes
in north-west Greenland did not exist until three years ago," he
said.
The accelerating thaw and
the earthquakes are intimately connected, according to Mr Kallio, as
immense slabs of ice are sheared from the bed rock by melt water. Those
blocks of ice, often more than 800m deep and 1500m long, contain immense
rocks as well and move against geological faults with seismic consequences.
The study of these ice quakes is still in its infancy, according to
Professor Correll, but their occurence is in itself disturbing. "It
is becoming a lot more volatile," said Mr Vallio. Predictions made
by the Arctic Council, a working group of regional scientists, have
been hopelessly overrun by the extent of the thaw. "Five years
ago we made models predicting how much ice would melt and when,"
said Mr Vallio. "Five years later we are already at the levels
predicted for 2040, in a year's time we'll be at 2050."
This dramatic warming is
being felt across the Arctic region. In Alaska, earthquakes are rocking
the seabed as tectonic plates – subdued for centuries by the weight
of the glaciers on top of them – are now moving against each other
again.
In the north of Sweden, mean
temperatures have risen above zero for the first time on record.
Professor Terry Callaghan
has been working in the remote north of the country at a research station
which has been taking continuous readings for the past 100 years. His
recent findings tally with the accelerating pace of change elsewhere.
"Mean temperatures have
remained below zero here since medieval times," said Professor
Callaghan. "Now, over the past 10 years we have exceeded zero,
the mark at which ice turns to water." Professor Correll said:
"We are looking at a very different planet than the one we are
used to."
© 2007 Independent News
and Media Limited
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