As most of you probably remember, much of the United States and Canada was hit with a sudden, extreme drop in temperature earlier this year. This deep freeze was caused by an atmospheric phenomenon known as the Polar Vortex, which keeps super-chilled air trapped in the Arctic, but occasionally allows some of the freezing Arctic air to escape and wander south.
The Arctic air can escape the Polar Vortex for a variety of reasons, but a group of scientists from South Korea and the United States revealed in a new study that this most recent incident was most likely caused by shrinking ice in the ocean’s northern seas, which causes more water to become uncovered.
Sea ice normally keeps heat energy from escaping the ocean and entering the atmosphere. However, when there’s less ice, more heat energy gets into the atmosphere and weakens the jet stream, which is what prevents most of the Arctic air from making its way south, according to the study’s co-author Jin-Ho Yoon of the Pacific Northwest National Laboratory in Richland, Washington.
The same thing happened back in the 1990’s, albeit rather infrequently, but it has turned into an almost annual occurrence since 2000. The scientists who made the study found that several such temperature drops happened just a few months after the ice levels in Barents and Kara seas, off of the northern coast of Russia, suffered from unusually low ice levels.
Using a collection of historical data and computer simulations, the group of scientists discovered a strong link between shrinking sea ice and the recent temperature drops, according to lead author Baek-Min Kim, a research scientist at the Korea Polar Research Institute. The vast majority of the melting sea ice is being driven by man-made climate change, according to Kim.
Read more about the story at Discovery.