As average temperatures rise throughout the planet, the frozen Arctic heats up faster than anywhere else.
With that heat comes a surprising turn: the unusually warm temperatures of the Arctic winter are related to bitter cold and snow in other parts of the northern hemisphere, such as the northeastern United States. UU., Parties from northern Europe and northern Asia, according to an analysis of 66 years worth of climate data.
And the relationship between Arctic heat and severe winter weather was strongest in the Northeast of the US. UU In fact, a temperature increase in the Arctic meant that the northeastern United States was two to four times more likely to experience extreme winter weather, the scientists reported in a new study. [The 10 Worst Blizzards in US History]
Previous climate projections predicted that, in a warming world, winters would be the stations to heat faster, and yet recent winters in the northern hemisphere were more severe than scientists anticipated, said Judah Cohen, lead author and director of seasonal study forecasts. at Atmospheric and Environmental Research, an organization that assesses the risks of climate events and climate change.
To understand what might be driving these unusual episodes, Cohen and his colleagues observed heat pulses in the Arctic during the winter months, to see how they aligned with climate anomalies in other parts of the world.
"When the pulse of the Arctic is warm, the occurrence of extreme winter weather in the mid-latitudes tends to increase, including the eastern United States, northern Europe and northern Asia," Cohen told Live Science .
The relationship between Arctic warming and cold bags to the south was "really, really strong", and was stronger in the US. UU., Said Cohen.
Since 1990, the US UU From the east they have been visited by winter storms so severe that they earned them highly dramatic nicknames, such as "Snowzilla", "Snowmaggeddon" and "Snowpocalypse". The increase in the incidence of extreme storms with heavy snowfall corresponded to periods of excessive Arctic temperature, the study authors wrote.
The disruption comes in waves
How does this relationship work? Because the scientists' observations reflected only the comparison of weather patterns over time – and not what drove them – the researchers could not conclude that a warmer Arctic was directly responsible for the harsh winter storms in the US. UU., They reported in the study.
But the answers may lie in another atmospheric disturbance linked to an Arctic warming, Cohen said.
According to the study, data from past decades showed that the snowpack in Siberia fell as the Arctic warmed, cooling the northeast of Eurasia. Meanwhile, melting sea ice fueled warmer temperatures in northwest Eurasia.
These changes in air temperature near the surface led to similar changes higher in the atmosphere. This, in turn, affected the jet stream (a wind conveyor belt that carries warm air and moisture around the globe) by increasing its "ripple", causing the air currents to dive further south and extend more towards the North. In turn, this additional amplification can alter the movement of masses of cold air near the pole, also known as polar vortex, Cohen explained.
And this alteration of the polar vortex could end up giving shape to the conditions that worsen the winter weather in the United States.
"The cold air that is normally confined to the Arctic is as if repressed by the polar vortex itself, because the winds normally blow from west to east inside the polar vortex, so it acts as a barrier, keeps the cold air north and the gentle air to the south, "said Cohen. "When it decomposes, the cold air that is enclosed in the Arctic spills in the lower latitudes, and that's when those episodes of severe winter weather occur."
Arctic scientists like to say that "what happens in the Arctic does not stay in the Arctic," but the interconnectivity between Earth's dynamic atmospheric systems is no laughing matter, Cohen said. The complexity of these systems is reflected in emerging disruptions that are likely to be the product of climate change, although there is still much to learn about how climate change could shape weather patterns around the world, the study authors reported.
"I would argue that our expectations about climate change were overly simplistic," Cohen said. "It was expected that if you heated the Arctic, the only thing that led to it was a milder temperature everywhere, and that is not a complete picture."
The findings were published online today (March 13) in the journal Nature Communications.
Original article on Live Science.