The freeze is on: from an annual low of ~5.1 m sq km at 15 September 2014, the sea ice that provides a hunting platform for polar bears is rapidly reforming.
Note that polar bear habitat world-wide is pretty well defined by the extent of sea ice in spring, with three notable exceptions. There are no polar bears (or fossil evidence of polar bears), in the Sea of Okhotsk, the Gulf of St. Lawrence, or the Baltic Sea.
Bears in some areas spend time on land in late summer/early fall but the amount of time varies widely.
Have a look at the maps below: the difference in regional coverage between the sea ice at 4 August and 16 October (73 days apart, both covering 7.3 mkm2) might surprise you.
Very good news for Barents Sea bears this year – they’ve had ice to the north all summer1 and even bears ashore on islands of southern Svalbard had a very short ice-free season (see previous posts here, here, here, and here). Ice also seems to be forming along the northeast coast of Alaska.
[All maps here courtesy National Snow and Ice Data Center (NSIDC, MASIE), my labels. Click to enlarge]
Breakup date average for W. Hudson Bay is July 1 – this year, it’s late again July 10, 2014
Natural selection helps polar bears adapt to sea ice variability – which means some bears die September 30, 2014
Footnote 1. Ice extent at the 2014 minimum shown below:
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