By
Theodora Filis
Until
this week, Europeans had been enjoying an unusually mild winter with
spring-like temperatures in many cities. Scientists say a string of
freezing European winters, scattered over the last decade, has been
driven in large part by global warming.
The
recent week-long cold wave, with temperatures plunging as low as
minus 32 degrees Celsius, has claimed hundreds of lives so far. Snow
has stranded travelers across the continent with roads blocked,
airplanes grounded, and trains unable to move. The snow is forecast
to intensify before easing on Saturday, February 4, 2012.
Big
Freeze tightens its grip on Europe
Meteorologists
blame the weather on a strong high-pressure system that has pushed
cold Siberian air across the continent. According to a new study
Arctic's receding surface ice, which at current rates of decline,
could disappear entirely during summer months by century's end –
tripling the chances that future winters in Europe and north Asia
will be just as bad as this year.
Bitterly
cold weather across Europe in the winter months of 2005-2006, dumped
snow in southern Spain and plunged eastern Europe and Russia into an
unusually, and deadly, deep freeze.
Another
long cold streak in 2009-2010, gave Britain its coldest winter in 14
years and caused transportation delays across the continent – much
like this week.
Climate
deniers who question the gravity of global warming say these bitter
winters are at odds with the standard climate change scenarios in
which Earth's temperature steadily rises, possibly by as much as five
or six degrees Celsius (9.0 to 10.8 degrees Fahrenheit) by 2100.
However,
scientists caution that these extreme winters mistakenly bring
together the long-term patterns of climate with the short-term
vagaries of weather, and ignore regional variation in climate change
impacts.
New
research shows that global warming has actually contributed to
Europe's winter frost.
Scientists
explain that the rising Arctic temperatures that have reduced
floating ice cover by 20 percent over the last three decades, and the
sun's rays that are now absorbed by dark-blue sea rather than being
bounced back into space by reflective ice and snow, together with
extreme heat, has created a strong high-pressure system that has
brought the cold polar air into Europe this week.
Stefan
Rahmstorf, a climate scientist at the Potsdam Institute for Climate
Impact Research in Germany said, "Say the ocean is at zero
degrees Celsius (32 degrees Fahrenheit), that is a lot warmer than
the overlying air in the polar area in winter, so you get a major
heat flow heating up the atmosphere from below which you don't have
when it is covered by ice. That's a massive change."
The
result, according to a modeling study published earlier this month in
the Journal of Geophysical Research, is a strong high-pressure system
over the newly exposed sea which brings cold polar air, swirling
counter-clockwise, into Europe.
"Recent
severe winters like last year or the one of 2005-2006 do not
conflict with the global warming picture, but rather supplement it,"
explained Vladimir Petoukhov, lead author of the study and a
physicist at the Potsdam Institute.
"These
anomalies could triple the probability of cold winter extremes in
Europe and north Asia," he said.
Colder
European winters do not indicate a slowing of global warming trends,
only an uneven distribution, researchers say.
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