After July's torrential flooding, the German village Insul in Rhineland was nearly destroyed. Boris Roessler/Picture Alliance/Getty Images
The polar jet stream, a wind band that separates the cold Arctic air from the warmer air to south, is known as the polar jet stream.
New research suggests that this band moves northward as the Earth heats.
This could lead to more heat waves and droughts in the eastern US and southern Europe.
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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 transporting the 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. The stream's delicate balance between warm and cold air 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 "onset" of the jet stream’s northward migration may already 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
NASA graphic showing the northern-hemisphere jet stream. NASA/Goddard Space Flight Center
The North Atlantic jet stream is a result of the collision between warm air from the tropics and Arctic air. These air masses will move east at 110 mph, driven by Earth's rotation, once they meet.
However, rising temperatures are disrupting this 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.
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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 looked at the stream's position over the past 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 continue at the current rate. The results revealed that the current wind band movement is likely to surpass any shift before it.
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.
On July 17, 2019, people cool down near Washington Square Park in New York City. Drew Angerer/Getty
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, semi-arid areas of southern Europe could become even more dry. Some parts of northern Europe, such as Scandinavia, that have already experienced a milder, wetter climate, may become even more so. Additional rainfall could lead to more floods, like those that plagued Europe in the summer.
The jet stream may change, which could also affect the polar vortices.
This is the location of the jet stream during the North American cold snap. It was February 15, 2021. The jet stream is shown in black lines. The white color indicates freezing temperatures. Mathew Barlow/University of Massachusetts Lowell
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 Arctic sea ice melting could increase the size and intensity of these deviating bulges. As sea ice melts more heat and moisture moves from Earth's surface upwards to space. It acts as a rock that is thrown into the pond. This creates ripples in the Arctic, which deforms the jet stream. This causes wiggles to push extremely cold air towards the equator.
On February 15, 2021, ice and snow covered roads in Odessa (Texas) Jacob Ford/Odessa American via AP
A weaker jet stream means more chances for intense winter storms or cold snaps in the US. This extreme winter weather is illustrated by the polar vortex that hit the US in 2019, and the winter storm in February that knocked out power to millions in Texas.
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 has the original article.
