Background:

Both Polar Regions – the Arctic in the north and Antarctic in the south – are covered by ice sheets throughout the year.  At both poles, part of each ice sheet rests on land, and part of each ice sheet floats on seawater.   The floating part is called “sea-ice”.  The area covered by sea-ice shrinks as the sea-ice melts in summer and grows when the sea-ice re-freezes in winter.   Scientists measure how the extent of sea-ice changes through the year using satellites.  The four box plots show the area covered by sea-ice by the Arctic and Antarctic ice sheets in late summer and in late winter.  Remember that in the Arctic, late summer is in September, and in the Antarctic late summer is in March!

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