Nasa Earth Observatory: Polar Sea Ice at Record Lows : Image of the Day
In March 2017, Arctic sea ice reached a record-low maximum extent, according to scientists at NASA and the National Snow and Ice Data Center (NSIDC). In the same month, sea ice on the opposite side of the planet, around Antarctica, hit its lowest extent ever recorded at the end of the austral summer—a surprising turn of events after years of moderate sea ice expansion.
On February 13, 2017, the combined Arctic and Antarctic sea ice numbers were at their lowest point since satellites began to continuously measure sea ice in 1979. Total polar sea ice covered 16.21 million square kilometers (6.26 million square miles), which is 2 million square kilometers (790,000 square miles) less than the average global minimum extent for 1981–2010. That’s the equivalent to losing a chunk of sea ice larger than Mexico.
The line graphs above plot the monthly deviations and overall trends in polar sea ice from 1979 to 2017 as measured by satellites. The top line shows the Arctic; the middle shows Antarctica; and the third shows the global, combined total. The graphs depict how much the sea ice concentration moved above or below the long-term average. (They do not plot total sea ice concentration.)
Arctic and global sea ice totals have moved consistently downward over 38 years. Antarctic trends are more muddled, but they do not offset the great losses in the Arctic. The maps below give a closer look at the record lows that occurred at each pole this year.
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