Since satellite records of sea ice began in the 1970s, the world's poles have shown a contrasting picture.  While Arctic sea ice levels have fallen steadily over the past few decades, Antarctic sea ice levels have shown a less clear trend -- increasing for several decades before falling to new lows in the last few years.

A recent study, led by AOS Associate Research Scholar Liping Zhang, offers a new theory that could help explain Antarctic sea ice changes. It suggests that, for the last few decades, natural fluctuations could have trapped heat deep in the Southern Ocean -- leaving surface water relatively cool and helping to protect the ice.  The paper, co-authored by AOS Faculty Member Tom Delworth, William Cooke (UCAR/GFDL), and Xiaosong Yang (UCAR/GFDL), was published recently in Nature Climate Change.

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