Global warming may shift the Arctic jet stream north, with dire consequences for Europe

Jet. We like to call it in French Jet. It is actually a streamsky Very strong. Works great. About 10 to 15 kilometers above the surface ar. It is several thousand kilometers long and several hundred kilometers wide. With notable consequences for weather forecast On the ground.

by Researchers from the University of Arizona (US) was particularly interested in: Jet from the North Atlantic. polar jet stream. Because yes, there are many jet streams around the Earth. The one who worries scientists today, this tape slots Common in the West, it mainly affects the weather in eastern North America and Western Europe. It is known to be responsible for 10 to 50% of changes in precipitation And temperatures are higher than these two major regions. But until now, researchers didn’t know much about how this jet stream evolved over time. And indeed, the way it might be affected in the future Global Warming humane.

To find out more, the team collected ice core samples from about 50 sites in Greenland. Enough to deal with changes in wind regimes since the eighth. to rebuild^NS century. Because the latter mainly causes differences in ice quantity that reach the ground.

If the jet stream is heading north…

Their results indicate that over annual or longer time scales, natural variability still masks the effect of global warming on atmospheric dynamics in averages. latitudes. But such large deviations can be recorded quickly. in the script business as usual – scenario in it emissions by greenhouse gases Continue as if nothing happened – and so models predict the northward migration of the polar jet stream from 2060. Migration is out of natural variance.

This is not good news. In fact, the researchers were also able to match certain changes in the North Atlantic jet stream with disasters that occurred in the past. For example, during the famine that struck the Iberian Peninsula in 1374, the polar jet stream was exceptionally northward. In 1740, half a million people died of starvation in the British Isles when the winds blew at half their usual strength.

We know that differences in the polar jet stream can have devastating effects on our societies. For example, by moving north, the jet stream takes moisture with it and exacerbates drought. The big difference from what could have happened in the past is that with anthropogenic global warming, this phenomenon could become permanent. But if our work sounds like another warning, we want to stress that we still have the power to control things.”Matthew Osman, lead author of the study, concludes: University of Arizona press release.