CREDIT: AP Photo / MTI, Janos Vajda
Global warming has doubled the chances that any given winter in Europe or northern Asia will be unusually severe, according to new research.
Specifically, temperatures have risen at the poles much faster than around the rest of the planet, leading to the collapse of Arctic sea ice coverage and altering weather patterns in the northern hemisphere. The research was recently published in Nature Geoscience, and relied on a the combined output of 100 different simulations — “the most comprehensive computer modeling study to date,” as The Guardian put it.
Several recent severe winters in Europe have already been associated with the recent years where the melting of the Arctic ice cap was most severe. And by the 2030s, the Arctic is expected to be completely free of ice in the late summer.
The finding pounds home the point that, rather than simply delivering an evenly-spread increase in heat around the planet, global warming leads to more instances of extreme weather in all forms, as well as wider swings to more extreme temperatures for different regions. “The origin of frequent Eurasian severe winters is global warming,” Professor Masato Mori at the University of Tokyo — the paper’s lead author — told The Guardian.
Multiple rounds of studies and modeling over the last few years have suggested that global warming could lead to temporary bouts of extreme cold over North America and Europe. Unlike Antarctica, there is no land beneath the Arctic ice cap. So as higher global temperatures melt the Arctic ice, more of the warmer ocean below is exposed to the air. That leads to heat and moisture increases in the Arctic atmosphere, which alters pressure patterns and air circulation in the northern hemisphere. Finally, those altered circulation patterns — particular a new “wobbliness” in the jet stream — yank the much colder Arctic air southward every so often, causing temporary bouts of extreme weather and colder temperatures in North America, Europe, and northern Asia. The “polar vortex” that swept across the northern United States this past winter, bringing storms and freezing temperatures with it, was an example of the phenomena.
“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,” Professor Adam Scaife, a climate change expert at the United Kingdom’s Met Office who was not part of the research team, also told The Guardian.
“The balance of evidence suggests this is real.”
The latest report from the Intergovernmental Panel on Climate Change (IPCC), due out November 2, will warn that climate change may have “serious, pervasive and irreversible” impacts on human society, according to Reuters. The IPCC has found a 95 percent certainty that global emissions of greenhouse gases from human use of fossil fuels have been the primary driver of global temperature increases since the 1950s. And because the effect of carbon dioxide concentrations in the atmosphere is cumulative, further global temperature increases and melting Arctic ice are a veritable certainty. But the report also added that “a combination of adaptation and substantial, sustained reductions in greenhouse gas emissions can limit climate change risks.”
Last week, the European Union actually struck an initial deal to cut the Continent’s emissions 40 percent below their 1990 level by 2030. It’s the first bid for reductions in the run-up to major international climate talks that will be held in 2015, and which observers hope will commit other major emitters like China and the United States to real and binding reductions. However, Europe and the rest of the world still have a very long way to go to get carbon emissions down to a level scientists and policymakers think is safe.
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