Sept. 13 (UPI) -- For just the second time since scientists started tracking Arctic sea ice coverage in 1979, the sea ice extent has dropped below 1.5 million square miles, or 4 million square kilometers.
Every autumn, the Arctic sea ice coverage reaches its minimum extent, before expanding as temperatures rise. Though the sea ice is still shrinking, the minimum extent still days away, coverage is already approaching record lows.
"Our satellite data show that between March and April 2019, there was an unusually large decrease in the ice extent, from which the Arctic sea ice was unable to recover," Christian Haas, a geophysicist at the Alfred Wegener Institute, said in a news release.
The Arctic's rapid springtime melting suggested sea ice coverage was destined for an all-time low, but fluctuating temperatures during the summer helped slow the retreat. Still, melting continued through the end of the summer.
Though temperatures have now dipped below freezing, heat retained by Arctic waters continues to melt sea ice. Though ice could continue to melt into late September, it's unlikely this year's minimum will surpass 2012's record low of 1.3 million square miles.
"Record or not, this year confirms the continued long-term reduction of Arctic sea ice as a result of climate change, making it ever more likely that in a few decades the Arctic will be ice free in summer," Haas said. "This will mean drastic changes in the Arctic, with consequences for the climate and ecosystems, as well as for people, including us in Europe."
Scientists at the Alfred Wegener Institute and the University of Bremen's Institute for Environmental Physics use satellite data to calculate the Arctic's sea ice coverage, as well as the thickness of the region's ice. Scientists also track atmospheric conditions, as well as air and sea surface temperatures, in order to better understand the factors that influence ice loss in the region.
Researchers are also preparing for a more intimate study of climate-ice dynamics in the Arctic. Later this month, the research icebreaker Polarstern will set sail in the Laptev Sea for the MOSAiC expedition. After locating a large pack of flowing ice to anchor to, the ship and its team of researchers will drift through the Central Arctic for 12 months.
According to Haas, who will join the second leg of the expedition, the low sea ice extent will make traveling easier, but the lack of ice will make it difficult to find a suitable large and stable ice float to connect the research vessel to.