The Arctic is undergoing a major shift due to climate change, and as the climate warms, its sea ice is melting at an alarming rate. A new NASA-led study sheds light on one of the consequences of this, with satellite data showing that melting sea ice is inundating one of the region’s most important ocean currents with fresh water, which scientists believe could have a ripple effect on the entire Atlantic climate.
For decades, scientists have been keeping a close eye on Arctic sea ice cover as an indicator of planetary warming. A 2016 NASA study found that total Arctic sea ice cover during the melting ice season was 40 percent lower than in the late 1970s. Last year, another study by the University of Exeter in the UK predicted that the Arctic Ocean could experience an ice-free summer within the next 20 years. Today, NASA estimates that Arctic sea ice is declining at a rate of 12.85 percent every decade.
In a new study, NASA scientists used 12 years of satellite data to track the behavior of one of the region’s major currents. Known as the Beaufort Gyre, this circulation is key to maintaining environmental balance, collecting fresh water from melting glaciers, rainwater and river water. But the team’s analysis shows that the Beaufort vortex is now taking in fresh water than ever before. According to scientists, this is due to the massive loss of sea ice in summer and autumn, which makes the Beaufort vortex more susceptible to wind.
Typically, the vortex gradually releases fresh water into the Atlantic Ocean, but these increased winds rotate it faster and faster, traping fresh water in the current. Traditionally, these winds change direction every five to seven years, but in the last 20 years they have been blowing westward. If the wind suddenly changes direction now, all the fresh water that accumulates can be pumped into the Atlantic Ocean immediately.
“If the Beaufort vortex releases excess fresh water into the Atlantic Ocean, it could slow down its circulation,” said Tom Armitage, a polar scientist at NASA’s Jet Propulsion Laboratory and lead author of the study. This will have an impact on the climate of the entire hemisphere, particularly in Western Europe. “
This is due to the interaction of the Beaufort vortex with another circulation that is important to the Earth’s climate, known as the Atlantic Trans-Flip Circulation (AMOC). When fresh water is released from the North Pole into the North Atlantic, it cools, sinks to the bottom of the ocean and pushes water south into the tropics, before bringing heat back from the tropics to the northern parts of the earth, such as Europe and North America.
A significant slowdown in the Trans-Atlantic Trans-Reversal Circulation could undermine one of the key systems regulating the Earth’s climate. To this end, scientists continue to closely monitor the Beaufort vortex. Alex Petty, co-author of the study, said: “This study shows that the loss of sea ice has a very important impact on the climate system we have just discovered. “
The study was published in the journal Nature Communications.