October 26, 2014

expert reaction to new study on Arctic sea ice and colder winters in Europe and Asia

A paper published in the journal Nature Geosciences has explored the link between declining sea-ice in the Arctic, and colder Eurasian winters. Loss of sea-ice can disrupt patterns of air flow of different temperatures at high altitudes leading to changes in weather, but the researchers’ models predicted that these colder winters were unlikely to continue with further increases in global temperatures.

Prof Peter Wadhams, Professor of Ocean Physics at the University of Cambridge, said:

“This is modelling evidence which supports the empirical analysis presented by Dr Jennifer Francis (Rutgers) which posits a link between summer sea ice retreat in the Arctic and a change in the position and shape of the jet stream, leading to blocking events and more severe winter weather over parts of the mid-latitude northern hemisphere.  In this case the modellers succeed in linking ice retreat to severe winter weather over Eurasia.

“Annual average global temperatures continue to rise, but the distribution of temperature through the year is giving us more extremes, which is highly damaging to food production.  As ice continues to retreat, we can expect these weather extremes to continue to occur and maybe worsen.”

Dr Colin Summerhayes, Emeritus Associate of the Scott Polar Research Institute, said:

“Using independent methods, this new study agrees with previous work by Kim et al that the increasing decline in sea ice cover in the Barents-Kara Sea area in early winter has led in recent years to unusually cold winters throughout Eurasia, including the UK.

“The warming of the atmosphere associated with the absence of sea ice weakens the high level winds of the polar vortex. That in turn leads to meandering of the jet stream, with the meanders becoming stuck. Meteorologists call this ‘blocking’. The stuck meanders pull cold air south out of the Arctic, and because they are stuck in position, the cold air supply can last quite a while.

“This new study found that the decline in sea ice has doubled the probability that there will be severe winters in central Eurasia. The authors agree that this state of affairs is unlikely to continue with further global warming. But other factors also influence the polar vortex that controls the jet stream. So, more research is needed to see how the interaction of all the controlling factors may affect the pattern of blocking in a warming world.

“This counterintuitive effect of the global warming that led to the sea ice decline in the first place makes some people think that global warming has stopped. It has not. Although average surface warming has been slower since 2000, the Arctic has gone on warming rapidly throughout this time.”

‘Robust Arctic sea-ice influence on the frequent Eurasian cold winters in past decades’ by Masato Mori et al. published in Nature Geoscience on Sunday 26 October 2014. 

Declared interests

None declared