March 22 (UPI) -- Earth's combined polar sea ice extent -- the total sea ice coverage on both the planet's poles -- hit a record low in March.
On March 2, Antarctic sea ice hit a record-low summertime minimum. On March 7, Arctic sea reached a record-low wintertime maximum.
The total sea ice extent for the two poles measured 6.26 million square miles, the smallest coverage measured since satellites began tracking sea ice in 1979.
The record lows in the Arctic aren't exactly surprising. Minimum and maximum extents have consistently shrunk over the last two decades. Warm water and warm weather late last fall ensured the trend continued, significantly delaying sea ice accumulation during the winter season.
"We started from a low September minimum extent," Walt Meier, a sea ice scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, explained in a news release. "There was a lot of open ocean water and we saw periods of very slow ice growth in late October and into November, because the water had a lot of accumulated heat that had to be dissipated before ice could grow. The ice formation got a late start and everything lagged behind -- it was hard for the sea ice cover to catch up."
Record sea ice lows in Antarctica are more surprising. The South Pole's ice extents were setting record highs only two years ago.
"There's a lot of year-to-year variability in both Arctic and Antarctic sea ice, but overall, until last year, the trends in the Antarctic for every single month were toward more sea ice," explained Claire Parkinson, a sea ice researcher at Goddard. "Last year was stunningly different, with prominent sea ice decreases in the Antarctic. To think that now the Antarctic sea ice extent is actually reaching a record minimum, that's definitely of interest."