When will polar bears become extinct if we carry on like we are?

Answer 1

Its unknown when polar bears will go extinct although some climate models are predicting an ice free arctic during thesummerwithin the next 20 years which will make it very difficult for polar bears to hunt their main prey of seals. Polar bears need sea ice to hunt and it is unlikely that pregnant females will be able to gain enough weight during the summer to allow them to stay in the den and nurse their young for the usual 5-6 months without food if their hunting habitat is gone. This means that more of the populations will be declining which is likely to lead to polar bears becoming extinct.

In 2009, the IUCN Polar Bear Specialist Group (PBSG) reported that of the 19 subpopulations of polar bears:

8 are declining, 3 are stable, 1 is increasing, 7 are without sufficient data

An estimate in this paper: Durner GM, Douglas DC, Nielson RM, Amstrup SC, McDonald TL, Stirling I, et al. Predicting 21st-century polar bear habitat distribution from global climate models. Ecol Monogr 2009;79:25–58: is predicting that two thirds of the current polar bear population will be gone by the middle of this century. I don’t know when they will likely go extinct but things are not looking very good right now.