Arctic losing long-term ice cover

The Arctic is losing its old, thick ice faster than in previous years, according to satellite data.

The loss has continued since the end of the Arctic summer, despite cold weather across the northern hemisphere.

Older floes are thicker and less saline than newly-formed ice, meaning they can survive warm spells better.

Ice more than two years old now makes up about 30% of all the ice in the Arctic, down from 60% two decades ago.

March is the month when the Arctic ice usually reaches its largest extent, as the dark winter nears its end.

Nasa’s data shows the area covered by ice is roughly the same as it was last year; but this masks a significant change.

“Although this March the area is slightly larger than last March, the area of [thick] perennial ice has reached an all time low,” said Seelye Martin, manager of the Cryospheric Sciences Program at Nasa headquarters in Washington DC.

“So the volume of Arctic ice continues to decrease.”

BBC