The Great White Bear (30 page)

And just three days after that discovery, the researchers made another: an adult male feasting on a yearling, which had been stalked and killed while it lay in a small pit in the snow. A rash of paw prints in the vicinity may have belonged to the dead cub's mother and siblings; but of the bears themselves there was no sign.

Many of the living bears the researchers found that year were in relatively poor condition; while offering the usual caveats of scientific uncertainty, they did not hesitate to suggest a relationship between the existence of thin bears and cannibalized ones. In twenty-four years of fieldwork in the southern Beaufort Sea, they wrote, never before had they come across signs of polar bears actively stalking and killing other polar bears.

Previously unseen, also, was the tragic tableau witnessed on the tundra of Hudson Bay, just outside Churchill, on November 20, 2009. The fall season had been warm and long; the shores were densely packed with hungry bears awaiting the sea ice that had yet to form. The visitors that day did not see the attack itself, did not document the moment when the male had attacked and killed the cub, but observed the aftermath. A struggle of sorts was evident as they approached; by the time they arrived on the scene, the cub was dead, the distraught mother alternately charging and then circling its killer. Perhaps attracted by the scent of death, other bears arrived; the male, which had begun to consume his quarry among some willows, moved the carcass to the coast to finish his meal in relative peace. The mother, as if still not able to fathom what had taken place, wandered the area looking frantically for her offspring. Where the male had begun to feast, she found her cub's pelt; picking it up in her mouth, she carried it away, swinging her head from side to side in obvious distress. Charging the other bears to keep them away, she kept the pelt firmly in her mouth until, finally, she placed it gently in the snow among the bushes, protected from the wind.

In 2007, in response to demands from environmentalists that it protect polar bears under the federal Endangered Species Act, the Bush administration directed the USGS to provide its best assessment of the species' status and future. The response was not encouraging.

Based on the best available estimates of climate trends and the likely response of sea ice to those trends, USGS scientists concluded that, by the middle of the twenty-first century, two-thirds of the world's polar bear population may have disappeared. It is possible, they wrote, that polar bear populations can survive in the Canadian Archipelago through the end of the century; if they do so, they could be the species' last survivors, and they would be much reduced in number. Elsewhere, polar bears would likely cease to exist within seventy-five years, and in some parts of their range—such as Hudson Bay and the southern Beaufort Sea—they could be gone within forty-five.

"I'm sure we'll still have polar bears around by the middle of the century and probably by the end of the century," says Steven Amstrup, the study's lead author, "but they'll be limited to portions of the Canadian High Arctic and adjacent Greenland, where the sea ice remains for longer, so they'll still have enough time to forage on marine mammals...[and] can survive through those periods when the ice is absent."

In a few select places, such as perhaps Wrangel Island, they may be able to persist by feeding on walruses that have themselves been forced ashore; but for the vast majority, living on land will not be an option. The brown bears that live in the regions where any newly terrestrial polar bears would be forced to try and eke out a living are the smallest brown bears in the world, and they are sparsely distributed, because the environment can support only grizzlies that are relatively tiny and few in number.

"It seems highly unlikely, then, that you could take the largest bears in the world and plunk them down on land in a habitat that only supports a very spare population of some of the smallest bears in the world," observes Amstrup. "You wouldn't do that and expect the polar bears to be able to survive. One thing we know is, polar bears don't go running around trying to figure out how to catch different kinds of food. Nowhere that we're aware of have they been successful in garnering much energy from anything except marine mammals that they catch from the sea ice."

Polar bears, in other words, may have descended from grizzlies, but there is no turning back to be like them again. They took a fork in the evolutionary road, and the path they have followed leads in only one direction. Polar bears have evolved to exploit a particular environment, a specific niche. In so doing, they have become a supremely successful predator, but while they may be the dominant predators in their chosen realm, without it they are doomed.

Polar bears are creatures of the sea ice. If it disappears, so will they.

The warmth of the freshly slain seal enveloped his face; its scent flooded his nostrils. At long last, the wait was over. The sea ice had returned, and with it a chance to satiate his hunger. He tore chunks of blubber from his victim, swallowing them ravenously as if he had no time to chew, so desperate was he to fill the void inside him.

The wait had been longer this year, the fast more demanding. It had eaten at him, increased his yearning for the hunt, a yearning that burned inside him still even as he devoured his first kill of the season. In others it had created desperation; one young male, anxious not to have to travel any farther after months without food, had even attempted to approach the breathing hole he had so studiously staked out. Such an act of impudence, and one he had punished, driving the intruder away until, defeated, the thin youngster had lain down in the snow and seemingly surrendered to the inevitable. As he swallowed, he looked over his shoulder to check that the stranger was not attempting to snatch his meal, but the interloper was not moving, showed no sign of stirring at all in fact, but remained where he lay, not offering any resistance as the drifting snow slowly covered him up.

The meal was finished. Only the remnants of a carcass remained. Still he was hungry. He closed his eyes and lifted his nose, sampling the scents that wafted through the air. He opened his eyes again and scanned the horizon. It was fiat, and still. He sniffed the air some more and then set off on his journey, across the ice.

The Nares Strait is
a narrow sliver of a passage, an undersized intermediary sliding between the closest points of Greenland and northeast Canada. The multichromatic mountaintops of Ellesmere Island glisten to the west, a giant's fingertips away from the slightly less imposing cliffs of Greenland to the east.

On a map it is barely noticeable, a cigarette paper's width lost in the morass of channels and islands of the Canadian High Arctic. For much of its recorded history, it has been a navigable passageway in name only; in winter, it is thick with sea ice that in summer melts and breaks apart one section at a time, granting only limited and temporary access.

The first section, toward the strait's southern end, normally breaks apart in late June, but its fracture provides no guarantee of a clear pathway. The ice takes weeks to fully break up and drift south, and it does so in the form of large floes and ice islands that are a navigational peril. By the time something approaching a negotiable route to the north opens up, a second restraining ice bridge—at the strait's very northern limit, on the boundary of the Robeson Channel and the Lincoln Sea—starts to fracture, flooding Nares Strait with old, multiyear sea ice from the Arctic Ocean.

In terms of oceanography and climate, that makes the Nares Strait, for all its apparent anonymity, of extreme importance, because it is one of only two outlets through which the Arctic Ocean can expel ice. But it also makes further passage precarious and ultimately—as temperatures drop with the onset of autumn and the ice fuses into an impenetrable barrier—once more impossible.

Prior to 1948, only five vessels had ever been recorded as traveling even as far north as Kane Basin, a slight bulge that marks the strait's approximate midway point. The ships that had pushed north of that point in the subsequent half-century were also relatively few in number, primarily powerful icebreakers that could grind through the gnarled floes. But now, at the end of June 2009, a small green ship—an icebreaker, yes, but on a far smaller scale than the behemoths that preceded it—sails defiantly and without interruption. On each flank of the ship's hull a rainbow rises from the waterline toward the bow, culminating in a white dove. Above the doves, in white lettering on either side, the ship's name.

It is the
Arctic Sunrise.

It had left Amsterdam two and a half weeks previously, and when its latest expedition had been conceived, there was no certainty it would be able to reach its destination, no guarantee that the
Sunrise
would be able to penetrate the southernmost ice barrier, or that, were it successful in that goal, it could successfully navigate the ice that would surely be scattered about the strait. But during the winter, ice had never fully consolidated, and by the time the
Sunrise
arrived, nary an ice floe was to be seen.

So the little ship sailed north, at no stage impeded by or even in sight of ice, until, 300 miles later, it had finally traveled as far north as it could. It had traversed the Nares Strait from south to north, the first ship ever to do so in June, but the pride in priority was countered on board by awareness of the possible ramifications. One swallow does not a summer make, but it was the second time in three years that winter ice in the Nares Strait had failed to consolidate fully. On the previous occasion, in 2007, a constant torrent of floes from the Lincoln Sea had flushed through from north to south all summer, but on this occasion, the ice bridge in Robeson Channel had held fast, and it was here, finally, that the
Arctic Sunrise
found its northward progress halted.

Ahead stretched nothing but the sea ice of the Arctic Ocean, 450 miles separating the
Sunrise
from the North Pole. There was need for caution: once the ice began to fracture and flood the strait, the
Sunrise
would have to flee or, at least, take shelter. A helicopter survey showed that, for now at least, the bridge was holding steady; from the air, too, there were abundant signs of the productivity of the ice edge, pathways in the snow where seals had slid into the water and, crisscrossing the ice like the feverish scribbling of a demented mapmaker, pathway after pathway of polar bear tracks, emerging from the distance, converging on the edge of the fast ice and patrolling its length, heading to breathing holes, crossing over pressure ridges, circling back and around, and eventually disappearing again.

And then, the crew of the
Sunrise
scarcely having had time to acknowledge their surroundings and finish breakfast, one of the bears appeared, carefully walking in the same prints that either it or another had left earlier and heading curiously toward the strange interloper into its world. For those who had been on board the ship in similar surroundings before, it was an omen: the first polar bear of the expedition, appearing on the first morning at the destination. Being the first, its every move was met with a cacophony of beeps and clicks as two dozen camera shutters fired off in rapid and ongoing succession.

The bear seemed fat and healthy, confirmation that the ship had entered productive hunting grounds, but for a good half-hour it appeared interested less in hunting than in examining the strange green iceberg that had appeared as if by magic. It sniffed the new smells the iceberg had brought with it; it examined the objects that strolled around on top and emitted peculiar noises. Occasionally, it wandered off to examine the edge of the ice, peering over the edge as if at its own reflection in the water and then looking back over its shoulder and baring its teeth as if the presence of the green iceberg, no longer a novelty, was now a source of confusion or displeasure.

For sixteen days the ship remained near the northern end of the strait, stationed alongside a glacier that the team of onboard scientists studied daily and intently, measuring movement and melt and the temperature of the water that lapped at its head until, eventually, the ice bridge broke. The Arctic Ocean displaced the
Arctic Sunrise,
its floes assuming their rightful place in the Nares Strait, their looming presence enough to prompt the ship's departure.

It would be a staged retreat; the ship would stay ahead of the ice and then, as if pressing itself in a doorway to avoid the passage of slow-moving Pamplona bulls, tuck itself into Kane Basin a while until it could stay no longer. And it was there, on a bright, sunlit Arctic night, that scientists and crew set off on a short boat ride to investigate an iceberg of exceptional beauty, nicknamed by those on board the "doughnut berg" for the almost perfect arch that it formed. Unlike many other icebergs, this was likely not a function of years of weathering but a feature with which it was created, the result of a channel in the glacier from which it calved.

The boat returned to the ship to pick up a photographer to examine the berg more closely, but as it neared its destination, the cry went out from above that a polar bear was approaching, at full speed. Vulnerable in their small craft, the boat crew fought their way through chunks of ice to reach the sanctuary of the pilot door and clamber onto the
Sunrise
; their safety assured, the mood of all on board shifted from anxiety to the relaxed confidence afforded by the protection of an icebreaker.

The bear approached, wading knee-deep through a melt pool in the ice, striding confidently toward the bow. It sniffed the air, looked up at those looking down, and for an instant appeared to crouch, as if measuring the distance and preparing to spring upward. Even from the safety of the bridge wing, thirty feet above its head, the bear's seemingly predatory focus unnerved. The bear completed its calculus and, having satisfied itself that any leap would fall short of its goal and be energy unnecessarily expended, snapped back to reality until, startled by the knock of a tripod leg against the steel hull, it whipped round and splashed into the water.