National Public Radio: In 2008, reports of polar bears' inevitable march toward extinction gripped headlines. Stories of thinning Arctic ice and even polar bear cannibalism combined to make these predators into a powerful symbol in the debate about climate change.
The headlines caught Zac Unger's attention, and he decided to write a book about the bears.
Unger made a plan to move to Churchill, Manitoba, a flat, gray place on the Hudson Bay in northern Canada accessible only by train or plane. For a few months out...