Conservation news

Sea ice extent tumbles around both poles in November

  • November was the seventh month in 2016 with a record-low sea ice extent in the Arctic.
  • The extent of Arctic sea ice typically grows beginning in September, thanks to lower air and water temperatures, but this year it contracted by some 50,000 square kilometers (19,300 square miles).
  • Warmer air around Antarctica diminished sea ice extent to 1.81 million square kilometers (699,000 square miles) below November averages recorded between 1981 and 2010.

Water and air temperatures and shifts in wind patterns conspired to hold down sea ice extent, setting record lows for the month of November in both the Arctic and the Antarctic.

“It looks like a triple whammy – a warm ocean, a warm atmosphere, and a wind pattern all working against the ice in the Arctic,” said Mark Serreze, director of the National Snow and Ice Data Center in Boulder, Colorado, in a statement.

The NSIDC tabulates satellite data on the extent of sea ice around the poles, adding to a 38-year satellite monitoring project. Usually, around this time of the year, dropping temperatures in the run-up to winter help Arctic ice freeze, a process that typically starts in September and peaks in March. Instead, at one point in mid-November, the extent of the sea ice had actually contracted by about 50,000 square kilometers (19,300 square miles).

The Arctic sea ice extent for November 2016 (white) was considerably lower than the median extent between 1981 and 2010 for the month. Figure courtesy of the National Snow and Ice Data Center

In some places, air temperatures topped out at 10 degrees Celsius (18 degrees Fahrenheit) above the averages recorded in November from 1981 to 2010. Consequently, the extent of the sea ice dipped to 9.08 million square kilometers (3.51 million square miles), nearly 18 percent lower than the November average.

Warming of the sea around Svalbard, an Arctic archipelago, had apparently stopped the freezing of ice altogether, said NSIDC scientist Julienne Stroeve in the release. Sea-surface temperatures in the area were up to 4 degrees Celsius (7 degrees Fahrenheit) higher than normal.

“Typically sea ice begins to form in the fjords at the beginning of November, but this year there was no ice to be found,” said Stroeve, who was in Svalbard last month.

Though the Arctic data is jarring, it follows a trend for the year: November was the seventh month of 2016 with record-low levels of sea ice.

What’s striking is the parallel decline in sea ice extent at the opposite end of the globe, NSIDC scientists noted.

The graph above shows daily Arctic sea ice extent as of December 5, 2016, with 2016 in blue, 2015 in green, 2014 in orange, 2013 in brown, and 2012 in purple. The 1981 to 2010 average is in dark gray. Figure courtesy of the National Snow and Ice Data Center

“The Arctic has typically been where the most interest lies, but this month, the Antarctic has flipped the script and it is southern sea ice that is surprising us,” said Walt Meier, a NASA and NSIDC affiliate scientist, in the statement.

With 2- to 4-degree Celsius (4- to 7-degrees Fahrenheit) spikes in air temperatures for this time of year and shifting winds that have moved around parts of the Antarctic ice pack, sea ice around the continent dropped precipitously in early November, to an average of 14.54 million square kilometers (5.61 million square miles). That’s 1.81 million square kilometers (699,000 square miles) below average, an area larger than Libya.

“Antarctic sea ice really went down the rabbit hole this time,” NSIDC lead scientist Ted Scambos said.


Banner image of broken floes of sea ice floating in the Weddell Sea courtesy of J. Beitler/National Snow and Ice Data Center