Though there are still some skeptics insisting that polar bears won’t be endangered, but the fact is polar bears’ populations are going into decline . The World Wide Fund for Nature (WWF) issues warnings that the polar bears’ subpopulations are accelerating downwards, from one to five during 2001 to 2006, with only 19 polar bear subpopulations left in the world. What is more serious is in early July that eight of the Arctic’s 19 polar bear subpopulations are in decline (Struzik). The International Union for Conservation of Nature (IUCN) reports that in Western Hudson Bay, their populations have fallen from roughly 1200 to 900 in the past two decades (Derocher). Some skeptics state that “polar bear have survived periods of warming that occurred during the last interglacial period, about 120,000 years ago, and the maximum temperatures of the last interglacial were roughly 2 degrees F of warning than now” (Struzik). But Derocher says that 120,000 years ago, there was no oil and gas development, no contamination or pollution of the environment, and moreover, people weren’t pumping greenhouse gases into the atmosphere like today. Since the situation is changed, there is no use in compare today to the 120,000 years ago, and suggest that this species will do just fine (Struzik). The simulation result shows that if the sea ice is melting one month earlier in Hudson Bay, there will be 40% to 73% rate of pregnant female polar bear can not successful fertility; and the rate will be get high as 55% to100% if the sea ice is melting in two month’s time. At that time, not only will the Hudson Bay’s polar bear population decrease, but also the whole Arctic polar bears as well (“Global Warming and Polar Bears”).http://www.polarbearsinternational.org/polar-bears/bear-essentials-polar-style/conservation/current-status
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