As a result of global warming, what evolutionary changes could we infer might eventually be seen in polar bears?

Loose of body hair, reduction of body fat percentage and changes in life habits.

Explanation:

One of the most notorious changes would be the loss of body hair, due to the temperature increase. The amount of hair that polar bears now posses, helps them with keeping their body warm in very cold temperatures, as well as the body fat, which would also be reduced because of the excess of heat. Finally, their life habits could also change, as for example, part of the body fat helps them with hibernation, so these periods could be reduced or even lost.