Arctic warming causes cold waves in the United States

This extreme weather episode also caused record damage, estimated at nearly $ 200 million.

Although it has now been confirmed that global warming causes powerful heat waves, the question of its effect on such cold waves is still under intense scientific debate.

For the first time, a large study was published in the journal Thursday Science In the Northern Hemisphere, not only in the United States, but also in Asia, it has been successful in showing the relationship between global warming and the changes in the winter solstice in the Arctic.

This pronounced warming in the Arctic feels very negative and unpredictable and it causes cold in other areas., One of the co-authors of the study, Matthew Barlow, agreed to AFP.

Furthermore, despite this paradox, researchers are categorical.

I was a little surprised that the results were so clear, we were able to get such a direct connection, Said a professor of meteorology at Lowell University in Massachusetts.

Two phenomena at work

The fastest warming region on the Arctic planet.

But two phenomena are actually at work: on the one hand, the rapid melting of sea ice and, on the other hand, an increase in ice cover, especially in Siberia.

Melting ice causes strong heat because the sea absorbs more heat, while extra snow in Siberia reflects more sunlight, causing it to cool slightly.

In an indirect and complex chain reaction, these two developments together lead to a revolt in atmospheric circulation.

The researchers focused on their effect on the polar vortex. These are strong winds that blow near the pole in winter, and are high in the stratosphere (the atmosphere is formed by the troposphere where we live, then above the stratosphere).

Typically, a polar vortex forms a circle containing cold air.

But with the impact of climate change in the Arctic, it weakens and becomes oval, Explain Matthew Barlow.

Rising atmospheric disturbances from the earth, more importantly, Bounce back Then when they reach the polar vortex, they are redirected towards the surface.

This change in the movement of depressions Pushes jet flow (Jet-stream In English) to the south, The researcher explains. A jet stream is a stream of air that blows from west to east.

And when you push the jet stream south, cool air comes with it.

The strength of this study is that it combines two approaches. First, an analysis of direct observations made over the past forty years.

The researchers selected periods in which the polar vortex expanded into an oval shape: so before each of these episodes, they observed a significant change in temperature in the Arctic, for example due to avalanches. . And in the weeks that followed, it was cold in North America.

Then, they used the weather pattern to verify the cause and effect relationship by changing the different parameters.

Good to anticipate winters

This innovation has many implications.

First, the detection of this mechanism makes it possible to better predict extreme cold waves, Maybe even several weeks ago, Matthew Barlow hopes.

This work also shows that although the earth is generally warming, it is essential to be better prepared for the potential for extreme cold waves.

Second, researchers hope that this warning will help inform the public about the global impact of the climate crisis, so there is a need to combat it by reducing greenhouse gas emissions.

Climate change in the Arctic is not just a cry for polar bears, At Martell Matthew Barrow. It can really affect you.