image: Antarctic sea ice concentrations in September 2018, at the annual maximum monthly ice extent (left), and December 2018, well into the decay season (right). view more
Credit: Image courtesy of Claire L. Parkinson and Nick DiGirolamo (NASA Goddard Space Flight Center, Greenbelt, MD).
A study examines changes in Antarctic sea ice over the past 40 years. The extent of Arctic sea ice has been declining since the late 1970s, consistent with global climate warming. In contrast, trends in Antarctic sea ice coverage have been positive over the same period, although with substantial decreases since 2014. Claire Parkinson analyzed satellite microwave measurements of Antarctic sea ice spanning the 40-year period 1979-2018. The yearly average sea ice extent for the Southern Ocean as a whole increased gradually from 1979 to 2014, reaching a record-high of 12.8 million km2 in 2014. Sea ice extent subsequently declined precipitously between 2014 and 2017, reaching a record-low yearly average of 10.75 million km2 in 2017, with a record-low monthly average of around 2.3 million km2 in February 2017. The trend in Antarctic sea ice extent over the entire 40-year record is positive, but with only half the magnitude of the 1979-2014 trend. The decline in yearly average sea ice in the Antarctic between 2014 and 2017 exceeds that observed in the Arctic over 3 decades. According to the author, the results provide further data for testing models of Antarctic sea ice and elucidating links between climatic modes and oscillations that drive sea ice changes.
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Article #19-06556: "A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic," by Claire L. Parkinson.
MEDIA CONTACT: Claire L. Parkinson, NASA Goddard Space Flight Center, Greenbelt, MD; tel: 301-614-5715; e-mail: <claire.l.parkinson@nasa.gov>
Journal
Proceedings of the National Academy of Sciences