Vladimir Petoukhov of the Potsdam Institute for Climate Impact Research in Germany and Vladimir Semenov of the University of Kiel used an elaborate model of air circulation to study the effect of a reduction of sea ice in the Barents-Kara Sea north of Norway and Russia. This region suffered a drastic reduction in ice cover during the cold European winter of 2005–06.

The researchers gradually reduced the values for sea ice cover in the eastern Arctic from 100 per cent to one per cent and analysed the results. ‘Our simulations reveal a rather pronounced non-linear response of air temperatures and winds to the changes in sea-ice cover,’ Petoukhov said. ‘It ranges from warming to cooling to warming again.’

Areas lacking sea ice transfer more heat from the ocean to the air. This can lead to anomalies in the atmospheric air stream, changing the direction in which winds blow and, in this case, bringing colder air down from the north.

‘Our results imply that several recent severe winters do not conflict with the global warming picture but rather supplement it,’ the researchers wrote in a paper that appeared the Journal of Geophysical Research.

January 2011