Polar bears having fewer cubs due to global warming - Telegraph

The study, published in Nature Communications, found that If the ice breaks up two months earlier than in the 1990s, 55 to a full 100 per cent of all pregnant female polar bears will not have a cub.

Polar Scientists Discuss Polar Bear's Fate - NYTimes.com

The thing that is sure is that 2009 and again 2010 were years when lots of cubs were produced. When Linda, Daryll Hedman and I flew the coast in mid July 2009 – Daryll and I were especially struck by the numbers of cubs. 2010 was similar.