Weather
goes haywire over Europe: scientists baffled by erratic swings of jet
stream
White Christmas for Moscow while south Europe sweats
24
December, 2012
From
deadly cold in Russia, floods in Britain and balmy conditions that
have residents in southwest France rummaging for their bathing suits,
the weather has gone haywire across Europe in the days leading up to
Christmas.
The
mercury in Moscow has fallen to minus 25 degrees Celsius (minus 13
degrees Fahrenheit) -- unseasonably cold in a country where such
chills don't normally arrive until January or February.
The
cold has claimed 90 lives in Russia since mid-December and 83 in
Ukraine, with eastern Eurasia in the grips of an unusually icy month
that has seen temperatures drop to as low as minus 50 degrees C in
eastern Siberia.
Another
57 people have died from the cold in Poland this month, and officials
say the icy front is probably "the most severe of the last 70
years," according to Regis Crepet, a forecaster with
Meteo-Consult.
While
the former Eastern bloc shivers and Britain fights severe flooding
after heavy rains, holiday-makers and residents in the south of
France and in Italy have dug out their shorts and swimwear to welcome
an unexpected blast of beach weather.
Temperatures
on Sunday climbed to 24.3 degrees C in Biarritz on the Atlantic
coast, nearly 12 degrees hotter than the seasonal average, and
nudging the 1983 record of 24.4 degrees C.
"These
are remarkable temperatures that we do not see every year,"
French weather forecaster Patrick Galois said.
In
Catania on Italy's Sicily coast, beach temperatures on Christmas day
are forecast to climb as high as 22 degrees C in some places, while
in Austria, the small village of Brand at an altitude of more than
1,000 metres (3,200 feet), noted a December 24 record of 17.7 degrees
C.
Tim
Palmer, professor of climate physics at Oxford University, told AFP
the weather extremes are explained by the northern hemisphere "jet
stream", a ribbon of air that speeds around the planet high up
in the atmosphere.
The
stream is akin to a length of rope "that you wiggle a bit",
said Palmer -- its undulations differing from year to year.
This
winter the jet stream is particularly wavy, pulling cold air in over
Russia from the far north, and bringing hotter air up from the south
over France and its neighbours.
"The
question: Is the waviness and the unusual configuration of the jet
stream the result of climate change? We don't know. The models are
probably not quite good enough to tell us," said Palmer, though
there was "some evidence" this may be the case.
"It
is quite possible that carbon dioxide (being pumped into the
atmosphere by human activity) is having the effect of making this jet
stream waviness more intense," said the weather expert, but
cautioned against apportioning premature blame for what may simply be
localised weather glitches.
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