The polar jet stream circles northern hemisphere and swirls up to nine miles high above our heads, like a curvy, ethereal crown.
This strong wind band separates the Arctic cold from the warmer south air. It is responsible for moving weather westward across the US and over the Atlantic to Europe. It determines how warm or wet these areas are.
A recent study has shown that the jet stream is moving north with rising global temperatures, according to an observation.
This is because the delicate balance between warm and cold air, which keeps the stream steady, is being disturbed.
The study concluded that if greenhouse gas emissions are not reduced, the jet stream could break out of its normal range by 2060.
Insider was told by Matthew Osman, a Climate Systems Center researcher at the University of Arizona, that the jet stream's northward migration might have begun.
This would cause severe weather disruption in the northern hemisphere and bring more extreme events such as droughts and heatwaves to the east and south of the US. Osman stated that more rain and flooding are likely in Scandinavia and northern Europe.
A migrating jet stream
The North Atlantic jet stream is a result of the collision between warm air from the tropics and Arctic air. These air masses will meet and move east at 110 miles an hour (161 km per hour) driven by the Earth's orbit.
However, rising temperatures can disrupt that hustle and flow.
On average, the Arctic is warming twice as fast as the rest. Because warm air travels further north than it finds cold air before reaching the Arctic, this causes the jet stream to move toward higher latitudes.
Osman observed that the jet stream's behavior is unpredictable. The band's position is affected by temperature differentials that cause it to fluctuate. His study, however, looked at the stream's location over 1,250 years.
The researchers used ice cores from 50 locations on the Greenland Ice Sheet to reconstruct the past behavior. These samples date back to the 8th Century. Cores showed how much snow had fallen and when.
The team then used climate models to simulate where the jet stream would move in the next four decades, assuming that greenhouse-gas emissions remain at their current rate.
Results showed that the current wind band movement is likely to surpass any previous shift.
It is expected to be significantly different from the norm with potentially disastrous consequences.
Osman stated that pushing the jet stream beyond its natural range could expose us to increasing climate risks.
There could be more flooding and droughts.
Osman's study indicates that the jet stream's movement will likely cause the US East Coast's temperature to rise faster than it is now, according to Osman. Both North America and Europe will be subject to more heat waves and droughts.
Osman stated that Europe, at the downstream end the North Atlantic jet will feel the most severe effects.
Particularly, the semi-arid areas of southern Europe could become even more arid.
Some parts of northern Europe, which already have wetter climates than Scandinavia, may become even more so. Additional rainfall could lead to more floods, like those that hit Europe this summer.
The jet stream may change, which could also affect the polar vortices.
Scientists believe that the jet stream will become more fluid due to warming.
Because not all warm and polar air move north at the same speed, the jet stream's path can be sinuous and meandering. The wind band is made up of many waves.
A study published last month suggested that the melting Arctic sea ice could increase intensity and size of these deviating bulges.
As sea ice melts more heat and moisture moves from Earth's surface upwards toward space. This acts as a rock being thrown into the Arctic pond. It creates strong ripples that alter the jet stream. This causes wiggles to push extremely cold air towards the equator.
A weaker jet stream means more chances for intense winter storms or cold snaps in the US.
This extreme winter weather can be seen in the polar vortex that hit the US in 2019, and the winter storm that knocked out millions of Texans in February 2019.
Osman stated that if the jet stream's waviness rises in the future, it could imply extreme events like the polar vortex might also become more common.
Business Insider originally published this article.
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