The pack ice arrives in Hudson Bay around the beginning of November and is only hard enough for a polar bear to walk on in late November/early December. With global warming, the ice is melting faster at the end of winter and therefore there is less time for the polar bears to hunt and feed before they have to retreat to the shores of Hudson Bay for the warmer summer months. In the 17th century the ice-free period in Hudson Bay only existed for around 4 months out of 12, the ice-free period has lengthened considerably in the last 30 years.
Global warming has a direct effect on the polar bears because of the importance of the pack ice. Because they fast during the summer, they have to rely on the fat reserves they have stored up over the winter hunt - the shorter the hunt season the less chance they have of survival. They are a symbol of global warming because with the ice melting faster, their species will die out. ... continue below the picture...
Polar Bear, Ursus maritimus, sitting in the brown/dry tundra in the Churchill Wildlife Management Area, Hudson Bay, Churchill, Manitoba, Canada.
Technical Information:
I photographed this photo with the digital SLR camera model Canon EOS-1Ds Mark II, aperture of f/5.6, exposure time of 1/400 sec. on ISO 200, as always I used a original Canon Lens, the focus lenght for this picture was 340mm.