“But at the other end of the spectrum, they continued, are four 'ice-obligate' species that depend on sea ice as a platform for hunting, breeding, and resting, and for which future prospects are dim indeed. They listed the walrus as one of those species; bearded and ringed seals were two of the other three ... the fourth member of the afore-mentioned 'ice-obligate' club, is, of course, the polar bear.”