Unlike the Northern hemisphere, where sea ice extent gives us a magnified and exaggerated look at how the planet is warming up, the Southern Ocean and the great Antarctic Continental Ice Cap tend to exhibit much more attenuated changes and much more stability.

But at this time of year, the start of winter in the North, the Antarctic is beginning its summer with an extreme deficit in sea ice. It may be that the Southern Ocean is now beginning to experience summer ice looses as severe as the Arctic Basin's over the last 40 years.

According to the National Snow and Ice Datacenter...

On January 1, Antarctic sea ice extent stood at 5.47 million square kilometers (2.11 million square miles), the lowest extent on this date in the satellite record (since 1978). This value is 30,000 square kilometers (11,600 square miles) below the previous record low for January 1, set in 2017, and 1.88 million square kilometers (726,000 square miles) below the 1981 to 2010 average. Extent declined at a rate of 253,000 square kilometers (97,700 square miles) per day through December, considerably faster than the 1981 to 2010 mean for December of 214,000 square kilometers (82,600 square miles) per day. Indeed, the rate of Antarctic ice extent loss for December 2018 is the fastest in the satellite record, albeit close to 2010 and 2005.

On December 26, Antarctic sea ice extent fell below the low mark for this date, set in 2016, and has continued to track below all other years. Notably, the November to December 2016 period was considered an extreme excursion of Antarctic sea ice at the time. However, since then Antarctic sea ice extent has continually remained below the 1981 to 2010 median and mostly below the interquartile extent (below 75 percent of the 30-year range of values). This change in behavior, which began during the austral spring of 2016, contradicts prior characterizations of Antarctic sea ice cover as slowly expanding, yet highly variable. Instead, another strong decline through late December 2018 has taken the extent below the November and December 2016 levels to new record lows.

It appears I will have to start paying more attention to the Southern Ocean in future reports. I will begin posting them here for you more frequently. The global warming we have seen in the Northern Hemisphere now seems to be unequivocally establishing itself in the South as well.