A bear lives, hunts, and watches the Arctic melt in ‘Ice Walker’

The polar bear’s den is a remarkable feat of evolution. After digging a depression in the snow, the bear settles in, her movement and temperature coordinating perfectly to create a chamber close to freezing, even as the winter Arctic air drops to some minus 40 degrees Fahrenheit.

Throughout her winter rest, the bear scratches and shapes a chimney, which allows fresh air in without undue heat loss. There is an exit tunnel, if she needs to escape quickly. The den eventually shapes into two chambers – the upper one is warmed by body heat and breath, offering a safe place for cubs starting life.

It is in one of these structures that Nanu, a polar bear sow at the center of Arctic explorer James Raffan’s book, “Ice Walker: A Polar Bear’s Journey Through the Fragile Arctic,” spends the first months with her cubs. And it is from here that the bears set out across the ice – part of an annual odyssey that polar bears have undertaken for millenniums. 

Nanu and her babies will walk across ice, and then the frozen mainland, for months. The Arctic, we learn, is full of hazards, even for an apex species such as the polar bear. There are solitary males who regularly kill cubs. There are wolves who would encircle and attack babies. And there are humans.

But the biggest challenge confronting Nanu and her family is the climate itself. Not the cold – Nanu’s body, as Raffan describes in exquisite detail, is as integrated into the Arctic as an ice flow. From the hollow, light-reflecting hairs that cover her body to a metabolism able to slow enough to preserve energy for months of fasting, Nanu has evolved in stunning harmony with her environment.

But this year, the climate – and the ice – have changed. The season during which the animals can hunt seal has shortened, and there are dangerous encounters with other species, from orcas to humans, whose ranges are newly overlapping. Even the landscape has altered, and oil-slicked water appears where once there would have been an ice bridge.

“Until very recently, the speed of change was gradual, so bears could mostly adapt as they went about their yearly cycles,” Raffan writes. “Today, climate change has accelerated in lockstep with technological progress, and that change now takes place much more rapidly. Nanu and her cubs are living in circumstances that ... will challenge their very survival.”

Raffan, who has spent years exploring, researching, and writing about the Arctic, is explicit about the fact that Nanu is a composite, a bear created from years of observation. But this is not fiction, he asserts. It is storytelling that transcends science – itself a limited language, and arguably one that has proved insufficient at conveying the magnitude of what we are about to lose.

It is, indeed, this storytelling that makes “Ice Walker” such a compelling, and poignantly painful, read. Raffan’s prose is lyrical. We see the beauty of the Arctic summer, when “meltwater pools transform the surface of the ice into a sun-warmed blotter of azure blue on white,” and we feel the dread when Nanu spots the “strange rainbow-coloured reflection of the night sky” around her cub, anticipating the damage that will come as he swims through it.

Critics may find fault with this invented bear family. Although Raffan avoids obvious anthropomorphism, there will be those skeptical about his attempt at a “bear’s-eye view.” Others might long for a “true” story – one real bear, unnamed, intimately studied and factually recorded.

Nonetheless, the emotional punch of Nanu’s tale, and the lessons it holds, are powerful. Although Raffan perhaps falls short in his goal of introducing the northern people he has long worked alongside, he clearly succeeds in his explicit goal to “explore a spectrum of ways in which humans know bears and how bears know humans.”

“Should we begin to appreciate fully the global changes wrought by human appetites,” he writes, “we might begin to understand that the threats to polar bears are also profound threats to us.”