One thing that puzzles some people about global warming is why, despite evidence of warming patterns on Earth, winters tend to be harsher and colder now than they were in the recent past. New research by scientists tied these colder winters to changes caused by the melting Arctic ice caps. The research shows that the melting Arctic ice caps at least double the risk of cold, harsh winters in Europe and Asia in the next couple of decades.

This process works because the more ice melts in the Arctic, the more cold winds circulate around the globe, causing a pattern which results in cold winters in Eurasia.

"The origin of frequent Eurasian severe winters is global warming," said Professor Masato Mori, one of the lead researchers on this study. Mori works at the University of Tokyo.

The new research was published on October 26 in Nature Geoscience.

Scientists believe that because the ocean is darker than ice and absorbs more heat, it warms the surrounding air, which creates a wind pattern called the polar vortex wherein winds are trapped in place. When winds from the Arctic region get trapped in this vortex, it creates severely cold weather.

The researchers wrote in the paper that the effects of these colder winters that are caused by melting Arctic ice will likely diminish in the future, since the Arctic is expected to be free of ice entirely during the late summers by the 2030s. If there is no more Arctic ice to melt in the late summer, it would stop the circulation patterns that are causing colder than usual winters elsewhere in the world. However, the researchers said that they are not sure yet about the time frame of these cold, harsh winters.

"The agreement between observations in the real world and these computer models is very important in giving us more confidence that this [doubled risk of severe winters] is a real effect. The balance of evidence suggests this is real," said Professor Adam Scaife, a climate change expert. Scaife was not part of the research team.

This research adds to the body of evidence that global warming is contributing not just to warmer weather but to extreme cold weather events. Climate change experts said that as more ice melts in the Arctic, these weather patterns might worsen. Global warming has already been linked to an increase in flooding, extreme heat waves, and other extreme weather events.