Climate and Environment, Feature
Sea Ice Sinks to Record Lows At Both Poles This Year
While Arctic Sea ice reached this year a record low wintertime maximum extent, sea ice around Antarctica also hit its lowest extent ever recorded by satellites at the end of summer in the Southern Hemisphere, scientists have said.
In February this year, the combined Arctic and Antarctic sea ice extent was at its lowest point since satellites began to continuously measure sea ice in 1979, said scientists at NASA and the NASA-supported National Snow and Ice Data Center (NSIDC) in Boulder, Colorado.
Total polar sea ice covered 16.21 million square km, which is two million square km less than the average global minimum extent for 1981-2010 — the equivalent of having lost a chunk of sea ice larger than Mexico, the study said.
“It is tempting to say that the record low we are seeing this year is global warming finally catching up with Antarctica,” Walt Meier, a sea ice scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in a NASA release on Wednesday.
“However, this might just be an extreme case of pushing the envelope of year-to-year variability. We’ll need to have several more years of data to be able to say there has been a significant change in the trend,” Meier added.
The ice floating on top of the Arctic Ocean and surrounding seas shrinks in a seasonal cycle from mid-March until mid-September.
As the Arctic temperatures drop in the autumn and winter, the ice cover grows again until it reaches its yearly maximum extent, typically in March.
The ring of sea ice around the Antarctic continent behaves in a similar manner, with the calendar flipped –it usually reaches its maximum in September and its minimum in February.
This winter, a combination of warmer-than-average temperatures, winds unfavourable to ice expansion, and a series of storms halted sea ice growth in the Arctic, the scientists said.
This year’s maximum extent, reached on March 7 at 14.42 million square kilometres, is 97,00 square kilometres below the previous record low, which occurred in 2015, and 1.22 million square kilometres smaller than the average maximum extent for 1981-2010, according to the scientists.