Save the whale? That’s so 1970s. Now it’s the mighty polar bear that has become the poster child of the environmental movement. But are polar bears really facing extinction, or are they just a photogenic vehicle for promoting alarm about global warming?
‘Adopt a polar bear’, suggests the green NGO, WWF. WWF will even give you a cuddly toy polar bear for signing up. ‘Many scientists believe polar bears could be gone from most of their current range within 100 years’, says the WWF website, citing climate change as the major threat to the bears. Earlier this month, the US tried – and failed – to persuade the Convention on International Trade in Endangered Species (CITES), to ban cross-border trade in polar bears and their parts. The US lists the polar bear as a ‘threatened’ species, while the International Union for the Conservation of Nature lists it as a ‘vulnerable’ species.
The major claim is that climate change is causing the sea ice in the Arctic to melt earlier and refreeze later. As the press release for a new paper in the Journal of Animal Ecology, released today, suggests, this makes life harder for polar bears. The paper’s researchers tracked female polar bears in the western Hudson Bay area of Canada from 1991 to 1997, and again from 2004 to 2009. According to the lead researcher, Dr Seth Cherry: ‘The data suggest that in recent years, polar bears are arriving on shore earlier in the summer and leaving later in the autumn. These are precisely the kind of changes one would expect to see as a result of a warming climate and may help explain some other studies that are showing declines in body condition and cub production.’
But before we start getting into a lather about the future of nature’s greatest land-based killing machines (sorry, I mean big furry canaries in the climate-change coalmine), it is worth noting that there are more optimistic voices around. Susan Crockford, an adjunct professor at the University of Victoria in Canada, has just produced a short paper for the Global Warming Policy Foundation (GWPF) called Ten Good Reasons Not To Worry About Polar Bears.
Crockford’s first point is that polar bears represent a ‘conservation success story’. The biggest threat to the bears in the past was hunting. Since 1973, when restrictions on hunting were introduced, it is commonly agreed that polar-bear numbers have bounced back from a low of around 10,000 to between 20,000 and 25,000. In addition, four sub-populations of polar bears are currently listed as ‘zero’, says Crockford, because they haven’t been surveyed. Add in those animals, and she argues that the true population figure could easily be between 27,000 and 32,000.
The only population shown to have declined in recent years – a fall in numbers described by Crockford as ‘modest’ – is the one in the western Hudson Bay area. Even here, claims that polar-bear numbers continue to decline are based on data that is ‘unpublished, woefully out of date, or both’, says Crockford. Polar bears have actually shown a remarkable ability to survive and thrive after months without food.
There’s also an assumption that the decline of Arctic ice in recent years must be due to manmade global warming, and that this change in ice conditions must be bad for polar bears. But global temperatures have barely changed since 1997, while the minimum level of Arctic sea ice has halved. That suggests other, more localised factors rather than global warming are responsible. Moreover, as Matt Ridley notes in an introduction to Crockford’s paper, the ‘ideal habit for polar bears is first-year ice that lasts well into the summer, when they feed on fat young seals… The recent trend in most of the Arctic – no change in winter ice extent but a decline in late-summer ice extent – has been towards exactly this ideal combination.’