Arctic sea ice, the subject of intense scientific scrutiny in recent decades as the planet gets warmer, has just set a new record — and it's a disturbing, worrying record, researchers say.
The record, which no one is high-fiving over, is an unprecedented "lowest winter maximum" for sea ice extent, recorded on Feb. 25, the researchers say.
The maximum has "not only occurred early; it is also the lowest in the satellite record," says the National Snow and Ice Data Center in Boulder, Colo., which tracks sea ice.
The new low, the smallest maximum extent since satellite records started in 1979, is yet more evidence of long-term climate change, experts say.
Having reached 5.6 million square miles — an area slightly larger than Canada — in late February, the sea ice floating on the Arctic Ocean is expected to begin to shrink with the spring thaw, they say.
It is possible there may be a late season surge in ice coverage with variations in natural conditions, they say.
The previous lowest observed maximum occurred in 2011, with this year's being around 50,2000 square miles below that, although the final extent could change "because in the last week the ice extent has been bouncing a bit up and down, and we realize that weather may still cause some late-season ice growth," says NSIDC research scientist Julienne Stroeve.
"I think, though, that it's unlikely that any late-season ice growth would result in a new maximum, but we've been wrong before," she acknowledged.
Still, experts say, the overall trend of diminishing sea ice covering is a clear sign of significant changes in the Arctic and around the world.
"This new data on sea ice loss sends a clear message to the global community that the Arctic is unraveling, warming twice as fast as the rest of the planet," says Rafe Pomerance, who chairs a group called Arctic 21, a collection of groups focusing on the Arctic.
A United Nations panel of climate scientists has linked the long-term decrease in ice coverage to climate change and predicts Arctic summertime ice could vanish entirely by the second half of this century.
It could even accelerate warming, experts explain, by exposing more open waters which, since they are darker than the ice, absorb more solar radiation and heat up the oceans.
Disappearing sea ice also has consequences for humans, they point out, citing the effect on Alaskan native villages whose residents have depended on subsistence hunting techniques from atop the ice for generations.