Scientists say thinning of the sea ice has reached even the coldest parts of the Arctic. Photograph: Nick Cobbing/Greenpeace
The oldest and thickest sea ice in the Arctic has started to break up, opening waters north of Greenland that are normally frozen, even in summer.
This phenomenon – which has never been recorded before – has occurred twice this year due to warm winds and a climate-change driven heatwave in the northern hemisphere.
One meteorologist described the loss of ice as “scary”. Others said it could force scientists to revise their theories about which part of the Arctic will withstand warming the longest.
The sea off the north coast of Greenland is normally so frozen that it was referred to, until recently, as “the last ice area” because it was assumed that this would be the final northern holdout against the melting effects of a hotter planet.
But abnormal temperature spikes in February and earlier this month have left it vulnerable to winds, which have pushed the ice further away from the coast than at any time since satellite records began in the 1970s.
“Almost all of the ice to the north of Greenland is quite shattered and broken up and therefore more mobile,” said Ruth Mottram of the Danish Meteorological Institute. “Open water off the north coast of Greenland is unusual. This area has often been called ‘the last ice area’ as it has been suggested that the last perennial sea ice in the Arctic will occur here. The events of the last week suggest that, actually, the last ice area may be further west.”
Ice to the north of Greenland is usually particularly compacted due to the Transpolar Drift Stream, one of two major weather patterns that push ice from Siberia across the Arctic to the coastline, where it packs.
Walt Meier, a senior research scientist at the US National Snow and Ice Data Center, said: “The ice there has nowhere else to go so it piles up. On average, it’s over four metres thick and can be piled up into ridges 20 metres thick or more. This thick, compacted ice is generally not easily moved around.
“However, that was not the case this past winter (in February and March) and now. The ice is being pushed away from the coast by the winds.”