For sea ice scientists, September is the time for polar highs and lows. Around mid-month, the Antarctic winter sea ice approaches its highest extent, while the Arctic summer thaw melts the region’s sea ice to its lowest extent. This year, Antarctic sea ice is shrinking to new winter lows for the second year in a row, with only 17.15 million km2 (6.62 million mi2) remaining on September 19, according to satellite records analyzed by the U.S. National Snow and Ice Data Center (NSIDC). This drop is almost one million km2 (roughly 400,000 mi2) less than the typical mid- September mean of about 18.5 million km2 (about 7.1 million mi2). But scientists say it may still be too soon to declare the winter sea ice annual maximum extent. In the Arctic this year, sea ice continues its multidecade downward slide, with just 4.28 million km2 (1.65 million mi2), making it the 7th lowest minimum in the satellite record, based on the NSIDC 5-day average extent. Polar researchers want to know: Is sea ice decline the new normal? “That’s the big question,” said Walt Meier, a sea ice expert with the NSIDC. “Is the Antarctic sea ice finally responding to global warming? Or is this just an extreme year or two?” Melting sea ice in the Arctic Ocean’s Canada Basin. Image courtesy of Jeremy Potter/NOAA. Southern sea ice setting record winter lows Historically, the sea ice that extends out from the edges of Antarctica has been far slower to respond to climate…This article was originally published on Mongabay
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