Britain can expect twice as many severe winters as usual over the coming decades, according to a study supporting the counterintuitive idea that global warming could lead to colder weather in some parts of the world.
Climate scientists believe they have found evidence to suggest that the loss of floating Arctic sea ice in the Barents and Kara seas north of Scandinavia can affect the global circulation of air currents and lead to bitterly cold winds blowing for extended periods in winter over Central Asia and Europe, including the UK.
The research, published in the journal Nature Geoscience, supports several previous studies published over the past few years that also indicate a change in the winter climate over Eurasia as a result of the loss of Arctic sea ice. Arctic sea ice has declined significantly over the past three or four decades.
However, the Japanese scientists who carried out the latest study said that the cooling effect is unlikely to last beyond this century. Rising global temperatures will eventually cancel out any localised cooling caused by loss of Arctic sea ice, although they said it is not possible to predict when this will happen.
Masato Mori, of Tokyo University, and colleagues from Japan’s National Institute for Environmental Studies and the National Institute of Polar Research, performed 200 slightly different computer simulations of the global atmospheric circulation based on actual sea ice measurements made since 2004, when there were years of high and low sea-ice cover in the Barents and Kara seas.
They found that a decline in sea ice was linked with a “blocking” pattern in the high-altitude atmospheric air currents. This blocking became twice as likely in low sea-ice years and it favoured the transport of cold, Arctic air south and west over Europe and Asia.
Colin Summerhayes, emeritus associate of the Scott Polar Research Institute in Cambridge, said: “This counterintuitive effect... 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.”
Professor Jennifer Francis, of New Jersey’s Rutgers University, one of the first researchers to make a link between loss of sea ice and changes to the jet stream, said: “Based on this new solid and convincing work, together with the other recent studies that support the existence of this particular mechanism, I think we can say this response is real.”
Big freezes: Britain at its coldest
2013: January and March brought two waves of heavy snow, causing chaos for travellers and closing schools.
2010: From late November to early December, heavy snow caused disruption across the country. Temperatures plunged too, with a low of -21.1C recorded at Altnaharra in the Scottish Highlands.
1963: The coldest winter since 1740. The sea froze in places, with blizzards and snow drifts across the country. Winter didn’t fully relax its grip until early March.
