http://www.guardian.co.uk/environment/2007/sep/04/climatechange
Loss of Arctic ice leaves experts stunned
David Adam, environment correspondent
Guardian Unlimited
Tuesday September 4 2007
The Arctic ice cap has collapsed at an unprecedented rate this summer
and levels of sea ice in the region now stand at record lows,
scientists have announced.
Experts say they are “stunned” by the loss of ice, with an area
almost twice as big as the UK disappearing in the last week alone.
So much ice has melted this summer that the Northwest passage across
the top of Canada is fully navigable, and observers say the Northeast
passage along Russia’s Arctic coast could open later this month.
If the increased rate of melting continues, the summertime Arctic
could be totally free of ice by 2030.
Mark Serreze, an Arctic specialist at the US National Snow and Ice
Data Centre at Colorado University in Denver, said: “It’s amazing.
It’s simply fallen off a cliff and we’re still losing ice.”
The Arctic has now lost about a third of its ice since satellite
measurements began thirty years ago, and the rate of loss has
accelerated sharply since 2002.
Dr Serreze said: “If you asked me a couple of years ago when the
Arctic could lose all of its ice then I would have said 2100, or 2070
maybe. But now I think that 2030 is a reasonable estimate. It seems
that the Arctic is going to be a very different place within our
lifetimes, and certainly within our childrens’ lifetimes.”
The new figures show that sea ice extent is currently down to 4.4m
square kilometres (1.7m square miles) and still falling.
The previous record low was 5.3m square kilometres in September 2005.
From 1979 to 2000 the average sea ice extent was 7.7m square
kilometres.
The sea ice usually melts in the Arctic summer and freezes again in
the winter. But Dr Serreze said that would be difficult this year.
“This summer we’ve got all this open water and added heat going into
the ocean. That is going to make it much harder for the ice to grow
back.”
Changes in wind and ocean circulation patterns can help reduce sea
ice extent, but Dr Serreze said the main culprit was man-made global
warming.
“The rules are starting to change and what’s changing the rules is
the input of greenhouse gases.”
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“If the rate is 0.3 °C per decade, 15 percent of
ecosystems will not be able to adapt. If the rate
should exceed 0.4 °C per decade, all ecosystems
will be quickly destroyed, opportunistic species
will dominate, and the breakdown of biological
material will lead to even greater emissions of
CO2. This will in turn increase the rate of
warming.
“According to the Intergovernmental Panel on
Climate Change (IPCC),the global average
temperature today is increasing by 0.2 °C per
decade.”
Leemans and Eickhout (2004) found that adaptive
capacity decreases rapidly with an increasing
rate of climate change. Their study finds that
five percent of all ecosystems cannot adapt more
quickly than 0.1 °C per decade over time.”
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