A record slow freeze of many regions of the Arctic this winter is making it harder for pregnant polar bears to find birthing dens. The delayed formation of sea ice during autumn has worried biologists, who fear a first “extirpation event” – the local extinction of a species – may be approaching faster than forecast for the most affected populations.

The waters around Svalbard, an archipelago between Norway and the North Pole, have a little over half the average area of ice for this time of year. According to the Norwegian Ice Service, the 172,291 sq km (66,522 sq m) of ice on 14 November was the lowest for this time of year since records began in 1967. October also saw a huge departure from previous trends, particularly in the Barents Sea, which had freakishly warm weather in February and August. Scientists say these shifts, which are caused by the manmade heating of the globe, are disrupting the behaviour of species that depend on thick winter ice, such as narwhals, seals, belugas and polar bears.(theguardian)…[+]