10 Things That Don’t Disprove Global Warming

Polar Bears Seem to Be Thriving
An increasing polar bear population is not necessarily a sign that global warming is a hoax. pum_eva/iStock/Thinkstock

One of the most compelling moments in the 2006 documentary "An Inconvenient Truth" was the animated sequence in which a polar bear in the Arctic Ocean was forced to keep swimming because it couldn't find ice upon which it could rest [source: Hammond]. So that's why climate change disbelievers have been gleeful about recent research suggesting that despite shrinking ice, the polar bear population in the Davis Strait area of eastern Canada actually has increased in recent years, to the point where it may be at carrying capacity — that is, the maximum number of bears that the area can support [source: Crockford].

But the polar bears' story may be a bit more complicated than it seems. For one, counting these animals is a tricky business, and the fact that the ice is breaking up weeks earlier than it did in the past (due to climate change) may actually make it easier for scientists to spot them by helicopter. This could inflate their numbers.

Even if the bear population is indeed increasing, this could be due to a 1980s European ban on the importing of baby harp seal hides, which has led to an increase in the bears' food supply. But as climate change worsens, that momentary brake on the polar bears' decline may not be enough [source: Unger].