Though scientists have long known that man-made climate change is a driving force behind the melting of Arctic sea ice, new research suggests that a large part of that loss may be the result of natural mechanisms.
Researchers have kept tabs on dropping sea ice levels for over a decade. However, they have never been sure why the melting process is occurring at such a fast rate. While there is no doubt some of it is driven by global warming, the ice is disappearing much faster than models predict it should.
To shed light on this mystery, a team of researchers from the University of California, Santa Barbara, looked at the September sea ice extent — or how much of the Arctic sea had at least 15 percent sea ice — and compared it to the summer’s atmospheric circulation. This revealed an odd trend in the data.
“There is a mismatch between the model’s output and the observation,” said lead author Qinghua Ding, a professor in the Geography Department at the University of California Santa Barbara, according to Popular Science. “Observation shows very fast, very abrupt sea ice melting, whereas the climate model cannot capture the fast melting.”
The team found that when climate change is not a factor, the North Atlantic Oscillation — a weather phenomenon that affects atmospheric pressure — causes large weather shifts throughout the Arctic. When the air circulates from left to right, it keeps the jet stream high, trapping cooler air in the Arctic. However, when it moves in the opposite direction, that cool air escapes and leads to warmer temperatures.
So, even without global warming, there would still be a lot of melting sea ice. In fact, the data shows that nearly 30 to 50 percent of Arctic melting is the result of these natural mechanisms. Humans make up the other 50 to 70 percent.
While these new findings are surprising, the team cautions that they do not mean climate change is not real or any less of a problem. Rather, the study simply sheds lights on a newly discovered phenomenon that may aid future research by helping scientists better understand how different weather patterns are connected to the melting ice.
“If this natural mode would stop or reverse in the near future, we would see a slow-down of the recent fast melting trend, or even a recovery of sea ice,” said Ding, according to Reuters.
The study is set to be published in the journal Nature Climate Change.