The polar vortex, which brought frigid temperatures to North America during the winter of 2013-2014 may have been caused by global warming, a new study claims.
North America, along with Europe and Asia could experience longer, more severe cold snaps as temperatures around most of the rest of the world continue to climb, according to the research team.
Shrinking ice sheets in waters off Russia could be driving the process. As coastal ice melts, heat would rise from the ocean into the atmosphere. This process would weaken air patterns in the jet stream that normally keep frigid air trapped in the northernmost regions of the globe. When this chilly air is released, it can travel south, causing temperatures to plummet in populated areas.
Researchers from South Korea and the United States studied the polar vortex and how it can be affected by the jet stream. This is a river of air, high in the atmosphere that normally keeps Arctic wind streams trapped in place. They found release of the polar vortex occurred infrequently during the 1990's but has taken place nearly every year since the year 2000.
Melting ice in the Barents and Kara Seas off Russia is driving most of the climatic change, according to the study. The investigation looked at historical records, comparing them to modern computer simulations. Each suggested a link between melting ice sheets and migration of the polar vortex into temperate latitudes.
Baek-Min Kim, a research scientist at the Korea Polar Research Institute, said that melting of the sheets is driven by the burning of fossil fuels.
Ice cover in the Arctic usually peaks each September. Measurements of the minimum ice extent are currently 40 percent lower than they were in the 1970's. A record low was reached in 2012.
Some climatologists believe that rising temperatures in the Arctic may be driving extreme weather conditions in temperate regions. This cutting-edge research is hotly debated by scientists, and many do not believe this effect can be significant. Supporters believe the new study shows a mechanism driving the process, as well as a virtual demonstration.
Kevin Trenberth, chief of climate analysis at the National Center for Atmospheric Research, is one of the investigators critical of the notion. He believes conditions over the Pacific are the underlying cause of the polar vortex migration. Climatologists are meeting to debate the subject and share data between research groups.
Study of the polar vortex and the jet stream was profiled in the journal Nature Communications.
