A major ocean current in the Arctic could reverse amid warming temperatures, a change which would bring significantly colder weather to western Europe, scientists at Nasa have warned.

The circular current, called the Beaufort Gyre, moves in a clockwise direction around the western Arctic Ocean, north of Canada and Alaska, where it naturally collects freshwater from glacial melt, river run-off and precipitation.

This freshwater protects sea ice from salty water which would melt it faster, and helps keep the north of the planet cool.

But increasingly rapid ice-melt due to climate change means the current has picked up unusually large amounts of freshwater and exposed it to the air, causing it to move faster and become more turbulent.

Using 12 years of satellite data, scientists have measured how this circular current has precariously balanced an influx of unprecedented amounts of cold, freshwater, and how this equilibrium could soon break down.

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REUTERS/Pinar Istek STRINGER Reuters Polar vortex brings temperatures colder than Antarctica to the US Chicago A shirt that was hung is seen frozen Terry Greenbeans/Reuters Polar vortex brings temperatures colder than Antarctica to the US Chicago People walk along the lakefront Getty Images Polar vortex brings temperatures colder than Antarctica to the US New York A young man waits on a subway platform in freezing temperatures AFP/Getty Images Polar vortex brings temperatures colder than Antarctica to the US Chicago Mist rises from the city and Lake Michigan EPA Polar vortex brings temperatures colder than Antarctica to the US New York People walk through the snow in lower Manhattan Getty Images Polar vortex brings temperatures colder than Antarctica to the US Chicago The James Versluis breaks ice on the frozen Chicago River near Navy Pier EPA Polar vortex brings temperatures colder than Antarctica to the US Michigan Aftermath of an accident in Grand Rapids, Michigan, U.S., January 29, 2019 in this picture obtained from social media. Picture taken January 29, 2019. JASON COFFELT/via REUTERS THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. MANDATORY CREDIT. NO RESALES. NO ARCHIVES SOCIAL MEDIA Reuters Polar vortex brings temperatures colder than Antarctica to the US Minneapolis Jen Brackman and Aaron Brackman don large jackets and goggles while on a walk on the Stone Arch Bridge on January 29, 2019 in Minneapolis, Minnesota. - The polar vortex is here -- tens of millions of people in the US braced on January 29, 2019, for a deep arctic chill, which authorities say could be life-threatening. Sub-zero temperatures already blanketing parts of Canada were already sweeping across the US Midwest and towards the East Coast. (Photo by STEPHEN MATUREN / AFP)STEPHEN MATUREN/AFP/Getty Images STEPHEN MATUREN AFP/Getty Polar vortex brings temperatures colder than Antarctica to the US Chicago epa07331480 Steam rises from the city as the sun rises in Chicago, Illinois USA, 30 January 2019. The US Midwest is bracing for a cold spell as a polar vortex sent temperatures plummeting below zero degrees Celsius. EPA/KAMIL KRZACZYNSKI KAMIL KRZACZYNSKI EPA Polar vortex brings temperatures colder than Antarctica to the US New York Man moves luggage in snow during a winter storm in Buffalo, New York, U.S., January 30, 2019. REUTERS/Lindsay Dedario LINDSAY DEDARIO Reuters Polar vortex brings temperatures colder than Antarctica to the US Chicago epa07330187 Ice and snow builds up along Lake Michigan in Chicago, Illinois, USA, 29 January 2019. The US Midwest is braced with a coldspell as a polar vortex sent temperatures far below zero degrees Celsius. According to meteorologists temperatures in Chicago area can drop to minus 31 degress Celsius (-25F). EPA/KAMIL KRZACZYNSKI KAMIL KRZACZYNSKI EPA Polar vortex brings temperatures colder than Antarctica to the US Chicago Ice forms along the shore of Lake Michigan before sunrise, Wednesday, Jan. 30, 2019, in Chicago. A deadly arctic deep freeze enveloped the Midwest with record-breaking temperatures on Wednesday, triggering widespread closures of schools and businesses, and prompting the U.S. Postal Service to take the rare step of suspending mail delivery to a wide swath of the region. (AP Photo/Kiichiro Sato) Kiichiro Sato AP Polar vortex brings temperatures colder than Antarctica to the US Michigan The city skyline is seen from the North Avenue Beach at Lake Michigan, as bitter cold phenomenon called the polar vortex has descended on much of the central and eastern United States, in Chicago, Illinois, U.S., January 29, 2019. REUTERS/Pinar Istek STRINGER Reuters Polar vortex brings temperatures colder than Antarctica to the US New York The sun rises behind icicles formed on the harbor in Port Washington, Wis., on Wednesday, Jan. 30, 2019. A deadly arctic deep freeze enveloped the Midwest with record-breaking temperatures. (AP Photo/Jeffrey Phelps) Jeffrey Phelps AP Polar vortex brings temperatures colder than Antarctica to the US Chicago CHICAGO, ILLINOIS - JANUARY 30: A commuter walks through downtown in sub-zero temperatures during an extremely light morning rush hour on January 30, 2019 in Chicago, Illinois. Businesses and schools have closed, Amtrak has suspended service into the city, more than a thousand flights have been cancelled and mail delivery has been suspended as the city copes with record-setting low temperatures. (Photo by Scott Olson/Getty Images) Scott Olson Getty Polar vortex brings temperatures colder than Antarctica to the US New York Geese huddle in the water as the sun rises at the harbor in Port Washington, Wis., on Wednesday, Jan. 30, 2019. A deadly arctic deep freeze enveloped the Midwest with record-breaking temperatures. (AP Photo/Jeffrey Phelps) Jeffrey Phelps AP Polar vortex brings temperatures colder than Antarctica to the US Chicago epa07330193 Ice and snow builds up along Lake Michigan in Chicago, Illinois, USA, 29 January 2019. The US Midwest is braced with a coldspell as a polar vortex sent temperatures far below zero degrees Celsius. According to meteorologists temperatures in Chicago area can drop to minus 31 degress Celsius (-25F). EPA/KAMIL KRZACZYNSKI KAMIL KRZACZYNSKI EPA Polar vortex brings temperatures colder than Antarctica to the US Minneapolis Icicles form outside a bridal shop on January 29, 2019 in Minneapolis, Minnesota. - The polar vortex is here -- tens of millions of people in the US braced on January 29, 2019, for a deep arctic chill, which authorities say could be life-threatening. Sub-zero temperatures already blanketing parts of Canada were already sweeping across the US Midwest and towards the East Coast. (Photo by STEPHEN MATUREN / AFP)STEPHEN MATUREN/AFP/Getty Images STEPHEN MATUREN AFP/Getty Polar vortex brings temperatures colder than Antarctica to the US Chicago A person walks along the lakeshore, Wednesday, Jan. 30, 2019, in Chicago. A deadly arctic deep freeze enveloped the Midwest with record-breaking temperatures on Wednesday, triggering widespread closures of schools and businesses, and prompting the U.S. Postal Service to take the rare step of suspending mail delivery to a wide swath of the region. (AP Photo/Kiichiro Sato) Kiichiro Sato AP Polar vortex brings temperatures colder than Antarctica to the US Chicago Icicles form on the walkway at North Avenue Beach of Lake Michigan in Chicago, Illinois, U.S., January 29, 2019. REUTERS/Pinar Istek STRINGER Reuters Polar vortex brings temperatures colder than Antarctica to the US Chicago epa07330640 Men walk by a sign warning of falling ice in Chicago, Illinois, USA, 29 January 2019. The US Midwest is braced for a coldspell as a polar vortex send temperatures far below zero degrees Celsius. According to meteorologists temperatures in Chicago area could drop to minus 31 degress Celsius (-25F). EPA/KAMIL KRZACZYNSKI KAMIL KRZACZYNSKI EPA Polar vortex brings temperatures colder than Antarctica to the US Chicago epa07331476 The sun rises over Lake Michigan in Chicago, Illinois, USA, 30 January 2019. The US Midwest is bracing for a cold spell as a polar vortex sent temperatures plummeting below zero degrees Celsius. EPA/KAMIL KRZACZYNSKI KAMIL KRZACZYNSKI EPA Polar vortex brings temperatures colder than Antarctica to the US Chicago CHICAGO, ILLINOIS - JANUARY 30: Commuters walk through downtown in sub-zero temperatures during an extremely light morning rush hour on January 30, 2019 in Chicago, Illinois. Businesses and schools have closed, Amtrak has suspended service into the city, more than a thousand flights have been cancelled and mail delivery has been suspended as the city copes with record-setting low temperatures. (Photo by Scott Olson/Getty Images) Scott Olson Getty

Since the 1990s, the gyre has accumulated a large volume of freshwater – 1,920 cubic miles (8,000 cubic km) – or almost twice the volume of Lake Michigan in the US.

The new study, published in Nature Communications, found the cause of this gain in freshwater concentration is the loss of sea ice in summer and autumn.

This long-term decline of the Arctic’s summertime ice cover has left the unfrozen sea much more exposed to the wind, which is therefore able to spin the gyre faster, trapping the freshwater in its current.

Persistent westerly winds have also dragged the current in one direction for over 20 years, increasing the speed and size of the clockwise current and preventing the freshwater from leaving the Arctic Ocean.

This decades-long western wind is unusual for the region, where previously the winds would change direction every five to seven years.

Scientists have been closely following the Beaufort Gyre in case the wind changes direction again.

If the direction were to change, the wind would then reverse the current, pulling it anticlockwise and releasing the water it has accumulated all at once.

“If the Beaufort Gyre were to release the excess freshwater into the Atlantic Ocean, it could potentially slow down its circulation. And that would have hemisphere-wide implications for the climate, especially in western Europe,” said Tom Armitage, lead author of the study and polar scientist at Nasa’s Jet Propulsion Laboratory in Pasadena, California.

This is because the release of the huge volume of freshwater from the Arctic Ocean into the north Atlantic could have a major effect on another vital ocean current system.

Freshwater is less dense than saltwater, so scientists fear the sudden release of thousands of cubic miles of freshwater could interfere with the current system known as Atlantic meridional overturning circulation.

This system keeps western Europe mild, due to the northward flow of warm, salty water in the upper layers of the Atlantic, and a southward flow of colder, deep waters.

Changes to this cycle could also affect the movement of organisms in the ocean, upon which many ecosystems depend.

“We don’t expect a shutting down of the Gulf Stream, but we do expect impacts. That’s why we’re monitoring the Beaufort Gyre so closely,” said Alek Petty, a co-author on the paper and polar scientist at Nasa’s Goddard Space Flight Centre.

The scientists said the results “reveal a delicate balance between wind and ocean as the sea ice pack recedes under climate change”.