Global Warming
S.O.S.
The Arctic is sending a clear distress signal: Life there as we know it is imploding in what may well be a harbinger of things to come for the rest of the world.
By Daniel Glick
On December 27, 2006, Interior Secretary Dirk Kempthorne proposed listing the polar bear as threatened under the Endangered Species Act (ESA). The announcement stunned some observers because the Bush administration had repea-tedly denied federal protection for other potentially imperiled species. Even more surprising, however, was the rationale for the administration’s polar bear proposal. In a potentially historic interpretation of the nation’s landmark environmental law, Kempthorne stated that the government would consider listing the polar bear under the ESA because a warming planet posed a grave challenge to the great white bear’s future survival. “We are concerned the polar bears’ habitat may literally be melting,” Kempthorne said.
His concern was reinforced in September, when the U.S. Geological Survey (USGS) released a series of studies that led its scientists to conclude that “future reduction of sea ice in the Arctic could result in a loss of two-thirds of the world’s polar bear population within 50 years.” The U.S. Fish and Wildlife Service will announce its decision regarding the polar bear listing in early 2008.
Whatever the formal outcome, the debate over the polar bear’s plight underscores how global warming presents a new, overriding challenge to conservation in the 21st century. Climate change has already affected half of the world’s wild species, estimates Camille Parmesan, a biologist at the University of Texas at Austin (see “Madame Butterfly,” Audubon, September-October 2005). She coauthored a 2003 paper with economist Gary Yohe in the journal Nature that arrived at a startling conclusion: A “coherent climate finger-print” has already affected thousands of plants and animals’ breeding, distribution, abundance, and survival rates by pushing species to migrate poleward or to higher elevations, by altering animal mating patterns, and by driving plants to bloom earlier. “That percentage was much, much higher than we expected,” Parmesan told me last summer. Perhaps nowhere are these trends more obvious than in the Arctic, where the temperature increase is occurring three to five times faster than the average global temperature rise.
For the polar bear, the top predator of an immense eco-system, these changes pose extraordinary challenges. Unlike their cousins the brown bears (called grizzlies in some places), polar bears are almost completely carnivorous. They rely on floating sea ice to hunt ringed seals, their favorite prey. Seals congregate along the ice edge because that’s where their food source—fish—lives. The fish live there because that’s where their food source—tiny marine inver-tebrates—congregates.
As the ice melts at record rates in a warming world, the polar bears’ ability to use their exquisite polar adaptations— camouflaged fur, huge paws that serve as paddles to navi-gate open water between ice floes, and the metabolism to weather long, minus-30-degree winters holed up in floating ice dens—may become more liability than asset. A polar bear decline could trigger what biologists call a “trophic cascade,” which, in its simplest terms, means a complete uncoupling of the Arctic food chain, with wildly unpredictable consequences.
In effect, the polar bear may simply represent the biggest canary in the coldest coal mine. Faced with thinning ice, slumping permafrost, disappearing glaciers, earlier spring thaws, and later fall freezes, animals uniquely adapted to the harsh circumpolar world face an uncertain future in a region that is defrosting under their paws and flippers. Human in-habitants of the north whose lives are intertwined with animal habits are taking note as well. In four trips above the Arctic Circle during the past four years, I have learned that the signs of global warming already permeate daily life. In Barrow, Alaska, whalers told me harrowing stories of drifting out to sea because the ice platform they were using became unmoored; in Nuiqsut, Alaska, Inupiaq subsistence hunters discussed how later freeze-up and earlier melt-off had already altered their hunting and fishing practices; and in Gravdal, Norway, fishermen feared that warming waters were moving cod schools farther offshore.
Scientists studying this vast region report that the signs of shifting Arctic ecology are subtle and perplexing, from changes in the productivity of invertebrates on the shallow seabed floor in the Chukchi Sea to the predation patterns of carnivores on the Arctic coastal plain. “What we can assume is that there will be effects in every part of the ecosystem,” says Andrew Derocher, a polar bear expert and Arctic ecologist at the University of Alberta. “The pace of change is so dramatically different than what we’ve seen in the past. It’s like taking a deck of cards, throwing a couple away, and reshuffling the deck. We’re just going to end up with different ecosystems.”
Derocher and other researchers have documented unusual behavior that brought the predicament faced by Ursus maritimus to the world’s attention: drowning polar bears, polar bear cannibalism, and Canadian polar bears growing steadily skinnier. But scientists have noted other strange animal happenings as well: walrus calves apparently aban-doned by their mothers in an oddly ice-free Arctic Ocean, red foxes preying on Arctic foxes near Prudhoe Bay, grizzly bears devouring more musk oxen on the Alaskan coastal plain, and Swedish reindeer herds dying because their foraging grounds turned into bulletproof ice patches during unseasonable freeze–thaw cycles. The numbers of some migrating water-fowl are plummeting, southerly gray whales have been over-wintering in the Arctic, and all five species of predomi-nantly subarctic salmon have been spotted near Barrow, the United States’ northernmost city. These and other puzzling observa-tions have prompted researchers to worry about how Arctic animals are faring—and will fare—in a rapidly warming world.
Early computer-generated climate models had predicted that as humans continue their profligate release of heat-trapping gases into the atmosphere, the Arctic would warm faster than the rest of the planet. The theory, reduced to its simplest terms, went like this: As the planet warmed, the white blan-ket of ice and snow that reflects sunlight would begin to fray, creating dark patches of gray-blue ocean and green tundra that absorbed more light. The warmer it became, the more the dark patches would expand, absorbing more light and further warming the region.
Those predictions of a “feedback loop” have been borne out by scientific observations around the circumpolar world. Vast regions formerly known as permafrost are now seasonal frost. Summer ice floes—frozen masses of seawater that float on the sea surface—now resemble dwindling ice cubes. The tundra is drying. Lakes and ponds are evaporating and becoming more brackish from saltwater intrusion because coastlines are eroding. Melting rates have increased even since the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report came out in early 2007 and concluded that the planet was “unequivocally” heating up and that humans were almost certainly responsible for much of the observed warming. Ever since the comprehensive IPCC report was issued, it seems as if there are almost weekly updates from scientists around the globe, most of which document faster and more extensive melting—of glaciers, sea ice, and the Greenland ice sheet—than had previously been measured. Most computer models of climate change forecast that these Arctic shifts are harbingers of what will happen in lower latitudes as greenhouse gases continue to force the climate to change at rapid rates.
The effects on Arctic ecosystems and the creatures that live and visit there are profound. Contrary to its perceived image as a wasteland of snow, ice, and permafrost, the Arctic is an extraordinarily fecund ecosystem that pops alive in the summer and provides a vital feeding ground and way station for hundreds of species, both terrestrial and marine— zooplankton to Arctic foxes, algae to walruses. Specially adapted marine mammals, including the ringed seal, and tiny terrestrial mammals like the collared lemming have figured out ways to make a living where other animals cannot.
The future picture for many Arctic species is far from clear, but ominous, suggestive outlines are taking shape for certain animals. Changing sea ice affects everything in the marine food chain, from benthic invertebrates to bearded seals. Warming tundra alters the terrestrial landscape, affecting everything from lichen concentrations to the foraging patterns of moose. Birds that commute to the Arctic from all over the world to mate, nest, and molt now find that spring arrives earlier than they do. Gray whales that migrate from Baja California, Arctic terns from Antarctica, and caribou that cross the formidable Brooks Range converge on this Arctic market, only to find that the food aisles have been moved around— maybe farther north, offshore, or even gone entirely. Insect products that used to be in the tundra section in, say, June are now gone by mid-May. Subarctic species, both plant and animal, are moving northward. Those that are already on the edge, like red phalaropes, dunlins, or Arctic foxes, have no place to go. “They are right on the fringe of the continent,” says Stan Senner, executive director of Audubon Alaska. “There is no other place to shift to.”
Plants and animals that have evolved over the past 800,000 years to live in or visit this icy world must now readjust to their shifting reality—or die. Many creatures may be able to adapt, and some plants and animals will surely thrive in a warmer Arctic. For others, a balmier world may spell difficulties if not doom. Birds like the king eider and the black guillemot are already being forced to modify their feeding, nesting, and reproductive behavior because of retreating ice conditions that move their food sources farther offshore. The Canadian government recently listed a herd of Peary caribou as a “species at risk,” partly because changing weather conditions have reduced food availability by coating forage in ice. Researchers worry that one Nunavut caribou herd, which annually crosses the frozen 25-mile-wide Dolphin and Union Strait between the mainland and Victoria Island, will no longer be able to migrate over the increasingly thin ice.
Ice-dependent mammals in particular are suffering observable distress in response to sea-ice reductions of the past few decades. Scientists had theorized that if the trends continue, the Arctic would be ice-free during the summer before the end of the century. These days it seems as if every new scientific paper predicts an earlier date for an ice-free season, now calculated to be mere decades away. In short, the not-so-distant future looks bleak—and not just for the polar bear. Ringed seals, bearded seals, walruses, narwhals, bowheads, and belugas face a particularly uninviting future, according to Henry Huntington, a lead author of the 2005 Arctic Climate Impact Assessment (ACIA), an international project that evaluated research data from around the region. “Arctic marine mammals,” he says despairingly, “are screwed.”
Floating in an ice-free Arctic Ocean on the 420-foot Coast Guard icebreaker Healy in the summer of 2004, Woods Hole Oceanographic Institution researcher Carin Ashjian and her shipboard colleagues were busy amassing data to document ways the marine Arctic ecosystem was changing. They had noted that warmer Pacific Ocean waters infiltrated the waters north of Alaska’s Point Barrow, bringing an unusual mix of new benthic invertebrates, zooplankton, copepods, and other marine organisms to the Chukchi and Beaufort seas. Ashjian was part of a crew that included lead researcher Jacqueline Grebmeier from the University of Tennessee, whose long-term studies of Arctic marine life made it clear that the ecosystem was in the midst of profound transition. “A change from Arctic to subarctic conditions is under way in the northern Bering Sea,” Grebmeier wrote nearly two years ago in the journal Science.
The ice-free summer of 2004 was particularly disquieting, because sea ice near shore is critical to jump-starting the Arctic summer feeding frenzy. (Sea ice comes in many forms, including floating pack ice and shorefast ice, which is attached to the land. Each form harbors its own ecological niches.) That frenzy, Ashjian says, begins with the return of the sun in mid-March, heralding the spring. During the next few months, ice starts to break up, and the light that infiltrates its edges provokes unicellular algae to bloom in sheets hanging, she says, like “a big shower curtain” from floes. Phytoplankton, another crucial strand in the food web, also begins to grow, filling the water column with dozens of varieties of tiny, drifting, plantlike one-celled organisms.
An explosion of life follows. Benthic invertebrates like worms, bivalves like clams, and filter feeders like brittle stars multi-ply on the shallow offshore sea shelf, feeding on phyto-plankton and the ice algae after it blooms and sinks. In turn, a variety of zooplankton, including shrimplike crustaceans called copepods, begin to proliferate, attracting other animals to graze on the invertebrate smorgasbord. Bottom-feeding waterfowl like spectacled eiders, copepod-chomping fish like Arctic cod, and clam-munching mammals like walruses gather to take advantage of the fleeting bounty. The floating ice is literally a movable feast—until the ice melts or moves so far offshore that the waters underneath become too deep and bottom feeders can no longer dive for their preferred diet on the shallow near-shore shelf.
As Ashjian and the research crew collected microinvertebrate samples and measured ocean temperature and salinity, they saw the first of what would be a recurring, disturbing sight: solitary walrus calves, approaching the research boat, barking incessantly. The calves were young, less than two years old, and normally would need to be near their mothers in order to nurse. First one motherless walrus calf came up to the boat, then another, then a pair. In the end, nine different walrus toddlers approached the researchers during their weeks at sea, each one barking constantly. “None of us had ever seen anything like this before,” Ashjian says.
The scientists knew that walruses normally use near-shore floating ice platforms to “haul up” and base themselves as they dive for clams and crabs on the shallow shelf that separates the shoreline from the deeper open sea. Calves normally wait on or near the floating ice for their mothers to return. Adult walruses can dive more than 600 feet to forage, but even if there had been ice floes where the researchers saw the calves, the ocean floor there was nearly 10,000 feet deep.
“There was no ice to be seen,” recalls Ashjian, and the baby walruses were obviously in dire straits. Each time one came near the boat, it would cry pitifully; sometimes this would go on for the entire 24 hours the researchers would stay in one place. Although the scientists were wary about anthropomor-phizing the animals’ behavior, the walruses were clearly in distress. “When a dog barks in the backyard all afternoon, you know they want something,” Ashjian says. The research-ers became increasingly upset with each orphaned walrus sighting, but the Marine Mammal Protection Act prohibited them from interfering. Documenting this grim Darwinian test in a paper published in the journal Aquatic Mammals, lead author Lee Cooper of the University of Tennessee concluded in chillingly dry language that “our observations raise the possibility that rapid seasonal sea-ice retreat could create a crisis for the Pacific walrus population in the Bering, Chukchi, and Beaufort Sea region.”
Warming waters clearly sealed the fate of the nine walrus calves Ashjian and her colleagues witnessed floating in an ice-free sea. “They had nowhere else to go,” she says. “We knew these animals were goners.”
Walruses are by no means alone in being pagophilic, or ice-loving, species—or in the problems they face as the ice re-cedes and thins. The startling observations of drowned polar bears, also in 2004 (the same low-ice year when Ashjian and her colleagues witnessed the walrus orphans), led research-ers to hypothesize that even these ursine marathon swim-mers could not negotiate the growing distances between ice floes and shore. Ringed seals, which provide the polar bear’s main sustenance, also make their increasingly precarious living along the edges of moving pack ice: diving for fish, pupping on the ice floes, and creating breathing holes where they secretively come up for air. Polar bears, in turn, stalk seals by day, camouflaging themselves near the breathing holes, ready to pounce. If predictions of further sea ice reduction come true, narwhals, bowhead whales, beluga whales, and other more seasonally ice-dependent animals will likely see their food sources float farther out to sea—or disappear entirely. As ice thins and moves away from shore, the consequences will ripple up and down the Arctic marine food chain. In July 2007 USGS scientists reported on a 20-year study of polar bear denning habits in Alaska that detailed a distinct increase in bears moving their den sites from offshore floating ice to land-based sites because of decreasing sea ice. One possible problem among many: Brown bears, which are omnivorous and better adapted to land-based foraging, will outcompete their carnivorous polar bear cousins if the polar bears are forced to spend more time on land.
Even without dramatic scenes of drowned polar bears and orphaned walrus calves, the prospect of a future world with less sea ice sends shivers down the spines of researchers like Henry Huntington of the ACIA project. Survival in the Arctic requires the careful and constant conservation of energy, he points out. If animals have to work harder to get to and from the ice where their food congregates, the consequences could be far-reaching. “There is really nothing promising for any of these species,” he says.
And as the impact from disappearing sea ice reverberates through the marine ecosystem, the plants and animals that reside in the terrestrial part of the Arctic face their own set of dynamic challenges.
Alaskan oil field security guard Bill Petersen saw what looked like a dogfight of sorts one night as he made his patrol. He probably didn’t realize he was documenting a likely symptom of global warming when he pulled out a video recorder during his night shift and filmed an unusual occurrence near Prudhoe Bay on Alaska’s North Slope: the predation of an Arctic fox by a larger red fox.
Petersen’s video captured a fight to the death, in which the red fox chased the white Arctic fox through a parking lot, then clamped its jaw on the Arctic fox’s neck and shook it until the smaller animal became still. The next scene showed a triumphant red fox carrying the limp carcass to a patch of snow, where it proceeded to eat its distant relative. (Arctic foxes and red foxes are from different branches of the canid evolutionary tree.)
After University of Alaska Fairbanks zoologist Erich Follmann got wind of the video’s Wild Kingdom content, he and his colleague Nathan Pamperin obtained a copy from Petersen. Follmann, who has studied Arctic foxes extensively, had been tracking various aspects of the species’ behavior for years. It was not unusual to see red foxes and Arctic foxes com-mingling in the area around Prudhoe Bay, but to the best of his knowledge, nobody had ever documented a similar killing.
Just as climate scientists warn that it is impossible to determine global climate trends by any single event—like Hurricane Katrina or a heat wave in Europe—biologists like Follmann caution against basing sweeping generalizations on drowning polar bears, barking walrus orphans, or even a red fox eating an Arctic fox.
Still, he says, the fox-on-fox killing was “noteworthy,” one of many signs of increasingly unusual animal behavior that appear to be popping up all around the terrestrial Arctic. At a time when warning signs are becoming clearer, warmer temperatures have rendered more northern climes hospitable for certain subarctic species. During the past 15 to 20 years, Follmann says, he has witnessed a northward movement in the range of red foxes, which will evict Arctic foxes from their dens. Follmann says that since the red fox is about twice as big as the seven-pound Arctic fox, with lankier legs and a bigger jaw, “the red fox is going to outcompete the Arctic fox—there’s no doubt about that.”
What’s more, his research included radio-collaring Arctic foxes and documenting how they, like marine mammals and polar bears, spend part of the year floating on ice floes, somehow scavenging a living far from marauding red foxes. That observation leads him to speculate that Arctic foxes will face increasing competition if they are forced to spend more time on land. Foxes are normally territorial and solitary, but in late summer and early fall that territoriality “breaks down,” says Follmann, especially if there is a whale carcass or human garbage to feed on.
If more Arctic foxes are forced to stay on land and more red foxes move north, that higher concentration of foxes will, in turn, facilitate the spread of diseases like rabies and canine distemper. “That’s something that’s definitely going to happen,” Follmann says. A northward spread of other diseases is also possible, according to other researchers, including chronic wasting disease and parasites that may affect other animals, such as caribou, musk oxen, and moose.
Arctic foxes play a pivotal role in the terrestrial Arctic ecosystem, and have a symbiotic relationship—conservation biologists would call it a “trophic interaction”—with snowy owls, jaegers, and federally threatened Steller’s eiders. This connection extends ultimately to the sedges, lichens, forbs, grasses, and mosses that feed small herbivores like voles and lemmings as well as grazers like caribou, moose, musk oxen, and reindeer. As with many trophic interactions, any perturbation in the system can set off a cascade of changes.
That’s what a group of Norwegian researchers, including Rolf Ims from the University of Tromso, have noticed in their studies of Arctic foxes, lemmings, and the Scandinavian Arctic ecosystem. They noted that the Arctic fox population was declining in Norway, and observed an “invasion” of the red fox. They wanted to find out if climate change could be the cause.
Foxes, snowy owls, short-eared owls, rough-legged buzzards, and lemmings are all part of the intertwined cycle of life in the Norwegian Arctic, and their populations rise and fall in historically predictable boom and bust years. Norwegian lemmings in particular are known for their impressive bursts of reproduction (females can breed at 16 days old, produce litters of more than a dozen little lemmings, and mate again a few hours after delivering). They also tend to experience population crashes every four years, for reasons that have produced dozens of theories but no prevailing explanation among experts.
Arctic foxes flourish in abundant lemming years and, in turn, have more than a dozen kits per litter when the rodent feast is in full swing. Snowy owls, too, dine on lemmings and enjoy banner reproductive years when lemming populations boom. The owls also fiercely protect their nests, and are big and vicious enough to keep foxes away. Such ground-breeding birds as geese and sandpipers have learned the value of the snowy owl’s protection, and so they often make their nests near the owls—which increases their survival rates.
Here’s where it appears climate change is disrupting this multi-species dance: Lemmings are herbivores, and the tun-dra ecosystem that includes their diet of sedges and mosses is undergoing profound shifts. For starters, vegetation changes in the Arctic include shrubs moving northward. Warmer temperatures have also evaporated many Arctic lakes; this, in turn, dries out the tundra and affects the growth of plants the lemmings love to eat. Lemmings do not hibernate, and they rely on an insulating cocoon of snow burrows and tunnels to survive. Since climate change in the Arctic is expected to bring warmer and more variable winters, with frequent thawing and icing events, small rodents like lemmings and voles will likely have lower survival rates and may not be able to rebound as easily from their regular population crashes.
As the five-inch-long lemmings go, Ims and a colleague suggest, so goes the food chain. When lemming numbers drop, so do the numbers of snowy owls. Foxes are embold-ened to raid geese nests for their eggs when the owl guard-ians aren’t present, and so on up and down the trophic cas-cade. If these trends continue, the researchers note, “the dynamics and structure of the tundra ecosystem will change quite dramatically.”
Scenes like the Alaskan fox fight caught on video and lemming-deprived red foxes pillaging goose nests may herald further changes in a warmer animal kingdom. In a seminal 2003 study about the potential national security threats posed to humans by global warming, researchers commissioned by the Pentagon reported that those who face hardships from its effects would likely treat their neighbors poorly. “Every time there is a choice between starving and raiding,” the authors wrote, “humans raid.”
Apparently, animals will as well.
There is another key Arctic mammal experiencing dramatic changes: Homo sapiens. Ever since the time some 12,000 years ago when Inuit people are thought to have crossed the Bering land bridge into present-day Alaska, humans have inhabited North America’s polar region. Today the lives and cultures of at least 40 different Arctic indigenous groups, including the Inupiaq from Alaska; the Inuit from Canada and Greenland; the Chukchi from Siberian Russia; and the Saami from Norway, Sweden, and Finland, are also at serious risk.
In Alaska, Inupiaq hunters are one more link in a food chain under stress. The changing migration patterns of the bowhead whales that have been the cornerstone of Inupiaq culture for millennia are wreaking havoc on a people already reeling from the clash between modernity and tradition. Even in the age of GPS, two-stroke snow machines, and telescopic rifle scopes, subsistence hunting provides a substantial share of many Inupiaq households’ groceries. Changing caribou migration patterns, later freeze-up, and earlier spring melt are all disrupting ancient human rhythms as well. In the Inupiaq village of Nuiqsut, for example, locals told me they customarily catch whitefish in the fall, traveling by snow machine down the Colville River to cut holes in the ice to fish. When freeze-up occurs later, it also means that the sun has set beyond the horizon for the winter, and their fishing expeditions must take place in the dark.
It is said that Eskimos have dozens of different words for snow, but Inupiaq whaling captain Eugene Brower told me it’s probable that there are even more Inupiaq words for ice. Piqaluyak is salt-free multiyear sea ice. Ivuniq is a pressure ridge. Sarri is the word for thick ice from the north; tuvaqruaq is old ice, and shorefast ice is tuvaq. For a whaler or bearded-seal hunter, these are not esoteric linguistic variations but the currency of survival for people who must know and follow ice patterns to track animals inextricably linked to their food supply and cultural rhythms.
There are no words, though, to describe how much, and how fast, the ice is changing. The tuvaq that once served as a staging area for crews during the spring whaling season used to be thicker, and stories abound from whaling captains and crews who cannot trust their years of experience to tell them which ice will be a safe platform to hunt from. “My greatest concern is with the loss of cultural identity of people in the north,” says Terry Chapin, an ecosystems ecologist at the Institute of Arctic Biology at the University of Alaska Fairbanks. As the animals that native peoples depend on become increasingly at risk, a way of life will disappear as well.
On top of that, humans are engaged in an ongoing fight about whether to allow increased oil development in Alaska, notably in the offshore areas of the Beaufort Sea and in the rich waterfowl molting area near Teshekpuk Lake in the National Petroleum Reserve-Alaska, west of the Arctic National Wildlife Refuge. Russia recently sent mini-submarines deep below the North Pole to make a disputed claim to the Arctic seabed in hopes of tapping oil and gas reserves, setting off an international rush to establish territorial control of the planet’s northern reaches.
Increased oil exploration may be just the tip of the iceberg. As Arctic conditions become milder, other commercial opportunities emerge from the melting ice. Already, fishermen and shipping companies are salivating over the possibilities of an ice-free summer to expand their territories. “It’s a double whammy,” says Steve Zack, a conservation scientist for the Wildlife Conservation Society, referring to the combination of global warming and the increasing development pressures brought on by the 6.6 billion people now inhabiting the planet. “The implications of all these changes are coming in at remarkable rates in the Arctic. It’s like an opening salvo in what will increasingly be true in the rest of the world.”
Daniel Glick is the author of Monkey Dancing: A Father, Two Kids, and a Journey to the Ends of the Earth (PublicAffairs) and is a contributing writer to the upcoming photo book The Last Polar Bear (Braided River).
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