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Extreme weather

Warmer in the Arctic, shivering in Europe. This is what scientists actually call ‘wacky’ weather

Freak Arctic weather may become more frequent with global warming

PUBLISHED : Tuesday, 27 February, 2018, 9:05am
UPDATED : Tuesday, 27 February, 2018, 9:43pm

A freak warming around the North Pole is sending a blast of Arctic cold over Europe in a sign of “wacky” weather that may happen more often because of climate, scientists said.

On the northern tip of Greenland, the Cape Morris Jesup meteorological site has had a record-smashing 61 hours of temperatures above freezing so far in 2018, linked to a rare retreat of sea ice in the Arctic winter darkness.

“It’s never been this extreme,” said Ruth Mottram, a climate scientist at the Danish Meteorological Institute (DMI).

Warmth was coming into the Arctic both up from the Atlantic and through the Bering Strait, driving and cold air south.

Around the entire Arctic region, temperatures are now about 20 degrees Celsius (36 Fahrenheit) above normal, at -8 degrees, according to DMI calculations.

To the south, a rare snowstorm hit Rome on Monday and some Brussels mayors planned to detain homeless if they refused shelter with temperatures set to fall as low as -10 in the coming week.

Hit by easterly winds from Siberia, cities from Warsaw to Oslo were colder than -8.

As long ago as 1973, a study suggested that an ice-free Arctic Ocean could make regions further south colder.

That “warm Arctic, cold continent” (WAC#C) pattern is sometimes dubbed “wacc-y” or “wacky” among climate scientists.

“Wacky weather continues with scary strength and persistence,” tweeted Professor Lars Kaleschke, a professor at the University of Hamburg. “The question is whether this weather will happen more often. This is just one event so it’s hard to make a causal relationship,” he said.

Some scientists say a long-term shrinking of sea ice on the Arctic Ocean, linked to climate change, exposes warmer water below that releases more heat into the atmosphere. That in turn may be disrupting the high altitude jet stream.

“The jet stream becomes wavier, meaning that colder air can penetrate further south and warmer air further north,” said Nalan Koc, research director of the Norwegian Polar Institute.

Arctic Ocean sea ice is at a record low for late February at 14.1 million square kilometres, according to the US National Snow and Ice Data Centre. That is about a million less than normal, or roughly the size of Egypt.

Erik Solheim, head of the UN Environment, said the rare weather fits a wider pattern driven by a build-up of greenhouse gases, mainly from burning fossil fuels from cars, factories and power plants.

“What we once considered to be anomalies are becoming the new normal. Our climate is changing right in front of our eyes, and we’ve only got a short amount of time to stop this from getting significantly worse,” he said.

Under the 2015 Paris climate agreement, almost 200 nations agreed to try to limit a rise in temperatures to “well below” 2 degrees above pre-industrial times, while pursuing efforts to limit it to 1.5 degrees.

The World Meteorological Organisation said the chill in Europe was caused by a “Sudden Stratospheric Warming” above the North Pole that led to a split in the polar vortex, a cold area of air above the Arctic that spilled cold south.

A big problem in working out whether the Arctic warmth is driven by human activities or natural variations is a lack of measuring stations.

There are no thermometers at the North Pole and satellite measurements go back only to the late 1970s.

On the Norwegian archipelago of Svalbard, temperatures were just above freezing, with rain, and about 13.4 degrees above the long-term average on Sunday.

“There have also been recent winters with similar deviations,” said Rasmus Benestad, senior scientist at the Norwegian Meteorological Institute.