Since the start of this century, polar bears have been an icon for all that’s worrisome about human-caused global warming. Polar bears are the most-used example to try and convince the public that burning fossil fuels already has had – and will continue to have – a harmful effect on the planet. As we are told the Arctic is warming twice as fast as the rest of the planet, the polar bear is often called the ‘canary in the coal mine’ for climate change (Linden 2000; Richardson 2020; Siegle 2018).
Polar bears have gone from being threatened with (or ‘vulnerable to’) extinction by overhunting in 1973, saved in 1996, and threatened by climate change in 2006. The scientists who make up the Polar Bear Specialist Group (PBSG) of the International Union for the Conservation of Nature (IUCN) were pivotal to these conservation decisions (Crockford 2017, 2019).
In 2006, the opinion of PBSG members was that polar bear numbers would decline by 30 % or more within the next 45 years because of predicted future declines in summer sea ice (ACIA 2005; Aars et al. 2006; Hassol 2004). This was the first time that future threats based on climate models had been used to declare a species vulnerable to extinction by the IUCN: it was a watershed moment for animal conservation.
By 2007, American biologists at the US Geological Survey (USGS) folded suit (Adler 2008). The USGS used computer models that depended on the opinion of just one biologist – Steven Amstrup – regarding how polar bears would respond to projected summer sea ice changes. The focus was on summer ice because spring, fall and winter ice model projections showed no significant change by mid-century while those for summer ice showed a dramatic decline (Amstrup et al. 2007; Durner et al. 2007; Holland et al. 2007).
Continue reading: The Polar Bear Catastrophe that Never Happened. By Susan J. Crockford.