The true cost of saving polar bears

In Nature Andrew E. Derocher comments on a paper by Amstrup et al. (also in Nature) that concludes that sufficient mitigation of greenhouse gas emissions would leave enough sea-ice habitat for polar bears. He writes:

This paper provides reason to hope that the previous predictions of declines in polar bear populations can be avoided if concerted efforts are made to reduce greenhouse-gas emissions. The threat posed by climate change to biological diversity has been clear for years, however, and calls for carbon sequestration and reduction of emissions to conserve species have largely gone unheeded.

There is cause for optimism, but that requires optimism about our ability to change.

Although Derocher does not mention that  "carbon sequestration and reduction of emissions" could have some costs for people, he is clearly sympathetic to human suffering:

Amstrup et al. also note that the best possible outcomes for polar bears include controlling hunting and other factors in an effort to make populations with the expected lower numbers sustainable. But a ban on hunting would be a serious cultural loss for the Arctic's aboriginal people.