Arctic sea ice thins in 2 big jumps, area weakens

Climate change attacked crucial Arctic sea ice thickness in two sudden big gobbles instead of steady nibbling, a new study says.

A little more than 15 years ago, sea ice quickly lost more than half its thickness, becoming weaker, more prone to melting and less likely to recover, according to the study that emphasizes the importance of two big “regime shifts” that changed the complexion of the Arctic.

Those big bites came in 2005 and 2007. Before then, Arctic sea ice was older and misshapen in a way that made it difficult to move out of the region. That helped the polar area act as the globe’s air conditioner even in warmer summers. But now the ice is thinner, younger and easier to push out of the Arctic, putting that crucial cooling system at more risk, the study’s lead author said.

Before 2007, 19% of the sea ice in the Arctic was at least 13 feet thick – taller than most elephants – but now only about 9.3% of ice is at least that thick. And the age of the ice has dropped by more than a third, from an average of 4.3 years to 2.7 years, according to the study in Wednesday’s journal Nature.

It cited “the long-lasting impact of climate change on the Arctic sea ice.”

“Ice is much more vulnerable than before because it’s thinner, it can easily melt,” said study lead author Hiroshi Sumata, a sea ice scientist at the Norwegian Polar Institute. Thicker sea ice is crucial to all sorts of life in the Arctic, he said.

The study shows “how the Arctic sea ice environment has undergone a fundamental shift,” said Walt Meier, a scientist at the National Snow and Ice Data Center, who wasn’t part of the research. “This paper helps explain why the sea ice has not recovered from those big drops.”