The 'onset' of the jet stream's northward migration may have already begun. By pushing the jet stream outside its already large natural range, we could be exposing ourselves to increasingly severe climate risks in the future. — Matthew Osman, a researcher at the University of Arizona's Climate Systems Center
The 'onset' of the jet stream's northward migration may have already begun. By pushing the jet stream outside its already large natural range, we could be exposing ourselves to increasingly severe climate risks in the future. — Matthew Osman, a researcher at the University of Arizona's Climate Systems Center
The jet stream has started an unprecedented shift north, which could wreak havoc on weather in the US and Europe
  • The polar jet stream is a band of wind that separates cold Arctic air from warmer air to the south.
  • A new study suggests that as the Earth warms, this band is moving north and out of position.
  • That could cause more droughts and heat waves in southern Europe and the eastern US.
The polar jet stream circles the northern hemisphere, swirling up to nine miles above our heads like a curvy, ethereal crown on the planet.

This band of strong wind separates cold air from the Arctic from warmer air to the south, and it's responsible for transporting weather from west to east across the US, over the Atlantic, and into Europe. It controls how wet and warm these regions are.

But according to a recent study, the jet stream is shifting north as global temperatures rise. That's because the delicate balance of warm and cold air that keeps the stream in place is getting disturbed. If greenhouse-gas emissions continue unabated, the study found, the jet stream will break out of its normal range by 2060.

"The 'onset' of the jet stream's northward migration may have already begun," Matthew Osman, a researcher at the University of Arizona's Climate Systems Center who co-authored the study, told Insider.


That would wreak havoc on weather in the northern hemisphere, bringing more extreme events like droughts and heat waves to southern Europe and the eastern US. More rain and flooding are expected in northern parts of Europe and Scandinavia, Osman said.

The North Atlantic jet stream exists and is held in place thanks to the clash between warm air zooming north from the tropics and cold air in the Arctic. Once these air masses meet, they move east at 110 miles per hour, driven by the Earth's rotation.

But rising air temperatures mess with that hustle and flow. The Arctic is warming twice as fast, on average, as the rest of the planet. So that warm air travels farther north before it finds cold air, which leads the jet stream's position to migrate toward higher latitudes.

... "By pushing the jet stream outside its already large natural range, we could be exposing ourselves to increasingly severe climate risks in the future," Osman said.

Osman's study suggests that the jet stream's migration will likely cause the US East Coast to warm more quickly than it already is. And both North America and Europe will experience more droughts and heat waves.

"Europe, on the downstream end of the North Atlantic jet, will feel these effects most acutely," Osman said.

In particular, semi-arid regions of southern Europe could become more arid. Parts of northern Europe that already have a wetter, milder climates, like Scandinavia, could become even wetter. That additional rainfall would prompt more floods like the ones that plagued Europe this summer.

Some scientists think that warming will also make the jet stream wavier than it already is.


The jet stream's path is meandering and sinusoidal because not all warm air moves north at the same rate, nor does all polar air travel south uniformly. Hence the many waves in the wind band.
Read the full article: https://www.businessinsider.com/jet-stream-moving-north-climate-change-weather-2021-9