A recent study performed by a team of American/Chinese scientists shows that there’s a direct link between the progressive shrinking ice in the Arctic and in the increasingly harsher snowy winters in the US, Europe and China.
In the year 2007, the level of Arctic sea ice hit a record low, which hasn’t recovered to this day. Since then, there’s been much more winter snow cover in large parts of the northern US, northwestern and central Europe and northern and central China, sparking researchers’ interest in the matter.
Of course, there have been a number of study previously released which discuss the impact increasing temperatures in the Arctic area, sparked by global warming, has on the weather. However, the present study goes a bit further, where others haven’t, and assess the strength of the cause-effect link.
“Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation,” says Judith Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech.
“The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents.”
The team of researches, headed by Jiping Liu from Georgia Institute of Technology in Atlanta, US, and the Insitute of Atmospheric Physics in Beijing, crunched numbers from data collected between 1979 and 2010, and observed a decrease in autumn Arctic sea ice of one million square kilometers corresponded to the greater increase in winter snow cover. A computer model was then put in place, which helped scientists discover two major factors that directly influenced the snowy winters of the past few years – a reduction of the northern jet stream strength, spurred by reduced air temperature difference between the Arctic and latitudes further south, over the Atlantic Ocean, and extra-atmospheric water vapor content, which makes the air more humid.
We think the recent snowy winters could be caused by the retreating Arctic ice altering atmospheric circulation patterns by weakening westerly winds, increasing the amplitude of the jet stream and increasing the amount of moisture in the atmosphere,” says senior research scientist Jiping Liu.
“These pattern changes enhance blocking patterns that favor more frequent movement of cold air masses to middle and lower latitudes, leading to increased heavy snowfall in Europe and the Northeast and Midwest regions of the United States.”
Computer simulations predict that within a certain time frame the Arctic might become completely ice-free in the summer and autumn – any time between 2016 and 2060. The researchers aren’t prepared, however, to claim whether the upcoming winters will get colder and snowier.
“It’s possible that future winters will be colder and snowier, but there are some uncertainties,” cautioned Dr Liu.
The researchers involved in the study, recently published in the journal Proceedings of the National Academy of Sciences (PNAS), stated that the next step in their work is to build various computer models of climate, and see whether they do forecast a growing winter chill.