Polar Meltdown
Is the heat wave on the Antarctic Peninsula a harbinger of global climate change?

By Charles W. Petit

PALMER STATION, ANTARCTICA–One doesn't need a Ph.D. to see that things are changing fast around here. "That's Dead Seal Point up there," says Ross Hein, 27, director of boating operations at this remote American research base. On a sunny January day–midsummer in Antarctica–he points the Zodiac inflated motorboat toward a low, rocky islet a mile or so east of the base. The tough, flexible bow bumps slowly through a shoal of ice chunks–some the size of golf balls, others as big as a refrigerator–shoved near shore by the wind and current. The hard ice gives the boat a ride like an old truck on a bad road. It leads into a startlingly beautiful passage several hundred yards long and 50 yards wide. "Two years ago," Hein marvels, "this wasn't even here."

The point is that Dead Seal Point has no point, for we clearly are passing behind an island. To the right is a long wall of extravagantly fractured ice high as a 10-story building. It is the leading edge of Marr Ice Piedmont, a glacial cap that reaches a depth of 2,000 feet on 38-mile-long Anvers Island, Palmer's home 120 miles outside the Antarctic Circle. Hein, to minimize hazards from falling ice, keeps well to the left, along a miniature, melting ice cap atop Dead Seal Point.

The spot's name stems, first, from the now vanished elephant seal that died on its seaward side a few yea rs ago. But what is more significant, the rock was once believed to be a peninsular point peeking from under the glacier's foot. Since the 1960s, Anvers Island's glacial mantle has pulled its skirts in by about 30 feet annually. The point turned out to be an island, one of many emerging along the shore. Thirty years ago, the then new Palmer Station was about 50 yards from the same retreating glacial front. Now it is a quarter-mile walk. An eerily beautiful ice cave nearby, today about 40 yards long and formed by a drainage channel along the glacier's base, was twice as long a decade ago.

If you think a few degrees of global warming would not mean much in your neighborhood, the word from Palmer Station is: Think again. While hardly warm here, what with icebergs like ivory cathedrals turning majestically in adjacent Arthur Harbor, it may be the most warmed-up place on the planet. It provides lessons for us all if, as many scientists believe, Earth is unstoppably entering a heat wave that could last centuries.

The Antarctic Peninsula is an S-shaped projection of mountains, geologically related to the Andes, that reaches 800 miles north from the main continent toward South America. The computerized climate models used to forecast global warming reveal no reason for this place to be warming more rapidly than the rest of the planet. But since the mid-1940s, the average year-round temperature on the peninsula has gone up 3 to 4 degrees Fahrenheit, and in the early winter (June in the Southern Hemisphere) it is up a startling 7 to 9 degrees. While it still snows year-round, with summer temperatures averaging a few degrees above freezing and the middle of winter running in the teens, the rate of warming is 10 times the global average.

On ice. The bulk of the continent has only warmed a degree or so in the same time. Even this is enough to make some climate scientists worry that a significant part of its ice cap could someday melt, raising sea levels precariously. But there is no sign of that yet, and the South Pole itself, atop a 2-mile-thick layer of ice where temperatures stay well below zero, may actually have cooled a bit. Such inconsistency is among reasons skeptics assert that global warming is too uncertain to merit costly programs to contain it.

But here warming is no mere hypothesis. And one senses how high the stakes are if the skeptics are wrong. The local warm-up is already in the same ballpark as that which the Intergovernmental Panel on Climate Change–set up in 1988 by the United Nations and the World Meteorological Organization to advise politicians–expects for the rest of the world during the next century.

The changes aren't subtle. One hundred miles to the east, on the other side of the Antarctic Peninsula, the immense and supposedly permanent Larsen Ice Shelf began to disintegrate in 1995. Nearly 1,000 square miles of shelf have collapsed just in the past two years, with thousands of square miles more appearing ready to go. "Climate change showed up on the radar screen 30 years ago or so, but most people back then never thought we'd really have to worry about it," says Bill Fraser, a tall, rangy ecologist and penguin specialist from Montana State University. He is the station's chief scientist and has been coming down here for two decades. "Now, right here, we're basically confirming what the models back then said would happen if climate changed. The species most vulnerable, those at the edges of their natural ranges, would be affected first. And that is what is happening."

In recent years, hints of wildlife migrations and local extinctions have been picked up around the world–butterflies moving to new ranges, for instance, or plants moving to higher altitudes on mountains. But the picture here is simpler and starker. Not only is warming greater but, except for the occasional scientist or carefully monitored tourist, direct human impact is scant. So one cannot blame wildlife changes on factors like toxic pollution, agriculture, or urbanization.

And wildlife shifts are unmistakable. Around Palmer and elsewhere on the western side of the peninsula there is not only less ice but a new set of residents. Southern elephant seals–the males are massive, sluglike beasts that can reach 8,800 pounds–usually raise their young farther north in more temperate climes like the Falkland Islands. But one day this summer 254 elephant seals, including many pups, were seen on just two islands near Palmer, with uncounted others presumably living up and down the coast. More hospitable weather is the only explanation scientists have for this sudden migration southward.

New colonies. Fur seals, too, were not reported here before midcentury. But five years ago, a research vessel counted 2,000 of them on just one island farther south. Similarly, gentoo penguins and chinstrap penguins, species common closer to South America but virtually absent in fossil deposits around Palmer, are establishing new colonies on the peninsula. And while nobody expects forests to appear on these icy plains, low grass, tiny shrubs, and mosses are thickening rapidly in many areas of the peninsula.

To see what such rapid heating does to a landscape and its wildlife, a U.S. News team visited Palmer in January, the height of austral summer. The peninsula has no airstrip, so it takes four days from Punta Arenas, Chile, across the Drake Passage aboard the Laurence M. Gould, an oceanographic research and resupply vessel under charter to the National Science Foundation. NSF manages the $200 million-per-year U.S. Antarctic program, and Palmer is one of the agency's premier sites for studying long-term ecological change.

At a glance the region looks much as it did to American seal hunter Nathaniel Palmer and other explorers who saw this part of the world in the 1820s. Palmer Station's small cluster of blue, corrugated steel buildings perch upon a rocky shore. Behind them the glacier extends as far as the eye can see. Inside the friendly base are laboratories, warm bunks, a good kitchen, and the "Penguin Pub" bar. Over the pool table is an old whale's rib, and above the fridge is an orange life preserver from the Argentine ship Bahía Paraíso, which sank after hitting nearby rocks in 1989. Its hulk is still visible from the station at low tide, and it still smells of the oil that wiped out a cormorant colony in the weeks after the wreck. Outside, gale-force winds can pour down the glacier without warning, sucking the warmth from anybody caught outside and not bundled up.

No passports. Palmer, with a maximum population of around 40 and an annual cost of $12 million, is one of three U.S. Antarctic stations and the only one on the peninsula. The main U.S. headquarters is McMurdo Station, nearly 2,500 miles away on the Ross Sea, where the population can exceed 1,000 people, and the other station is at the South Pole. Like all of Antarctica, the peninsula is a utopia of international cooperation. No one needs a passport to be here. The 1959 Antarctic Treaty suspended all territorial claims and reserved the great white continent for scientific research.

Fraser, 49, came here as a grad student and soon after did a 14-month sojourn. He makes no secret of the fact that he loves Adélie penguins. Changes here are not limited to new species moving in. Indeed, the Adélies are dying off, and fast.

Imagine a flock of turkeys trying to bleat like sheep, amplify it a few times, and that is the sound of a colony of Adélies. They are packed into nests of small pebbles stained pink with guano, and one often smells their raucous colonies before hearing them. Analysis of debris under nesting sites indicates that Adélies have dominated bird life around here for at least 600 years. And, to a first-time visitor during nesting season, Adélies seem to be waddling comically everywhere on the small offshore islands or slicing swiftly through the waves and dodging fierce leopard seals that prey upon them.

But 25 years ago more than 15,000 pairs of the penguins nested yearly within about 2 miles of the base. This year, there are about 7,700 of the handsome, formal-clad couples raising young. The population is down 10 percent in just the past two years. One soon learns to recognize the silent expanses of pebbles that mark extinct colonies.

On Torgersen Island, about half a mile west of Palmer, Fraser quietly watches and counts the birds as they come and go or tend their nests and their chicks. The chicks are about two-thirds the size of an adult and covered in gray down. But in addition to taking a census of the Adélies, Fraser wants to know what the birds are eating. "You know how the old-timers did this?" he asks. He takes aim down an imaginary rifle barrel. "Plink! I just don't think I could ever do that. No way."

Instead, he and co-researcher Donna Patterson select five of the 18-inch-high Adélies as they hop across the rocks, tummies plump from foraging at sea. After a short chase, they drop a net over each bird, pick it up by the base of a flipper, and carefully measure its skull and beak size. While Fraser grips the bird's torso between his knees, Patterson gets behind him to hold its calloused, sharp-nailed feet. Field assistant and graduate student Erik Chapman dips a clear, flexible tube in olive oil. He passes the tube to Fraser, who with a look of apology on his face, slides it down the penguin's throat. Turning a hand crank, Chapman pumps warm salt water into the bird's stomach. In a moment, the bird regurgitates the water, along with its recent meal.

Stoics. Bird by bird, the researchers fill small plastic bags with disgorged krill, the shrimplike plankton that are the near-exclusive fare of penguins here. Except for a slight pink color from exposure to digestive enzymes and acids, the limp crustaceans look fresh. A pair of brown skuas –powerful predatory relatives of gulls that fly like eagles and often consume stray penguin chicks–alight nearby. They know they'll get some leftovers tossed to the ground by the scientists. As far as can be told, the procedure does the penguins no harm. They endure it with impressive equanimity. Upon release, each scrambles away, flippers flapping, then resumes a deliberate walk back to the colony where mate and offspring wait.

An hour or so later, Bill, Donna, and Erik are back at a lab bench on Palmer's ground floor, picking through the erstwhile penguin meals with tweezers, measuring each of the krill against a ruler. To the untrained eye they don't look ominous–fat and near the 2.5-inch maximum length that these krill reach. But Fraser sees something else. "This looks bad," he says, laying a few krill upon the lab bench's black surface. Such big krill are at least three years old. Young krill depend in their first winter on shelter under the solid ice that forms on the sea surface. The absence of young krill in these Adélies' diet reinforces Fraser's fear that this food source could collapse if winters around here remain as warm and ice free as they have become. Recently, winter ice is getting rarer. At midcentury 4 out of every 5 winters here produced extensive sea ice. Now, just 2 in 5 bring the heavy winter ice necessary to shelter the young krill.

As early as the mid-'80s, researchers at Palmer could see the local Adélie population dropping. At the same time, chinstrap penguins, almost unknown here before the late 1950s, were (and are) prospering, sometimes walking right into Adélie rookeries and setting up housekeeping flipper to flipper with their cousin species. And while krill may be down, both penguins eat them, so a food shortage seemed an unlikely way to explain their differing fates. Except for a dark line under their beaks, chinstraps look a lot like Adélies. And for a long time scientists knew of no significant behavioral differences between the species that would explain why one might do better than the other. A big clue came in the coldest, darkest months of 1988. That year the U.S.-chartered research vessel Polar Duke explored the Weddell Sea on the east side of the Antarctic Peninsula. The expedition, with Fraser on board, found the winter ice pack swarming with Adélie penguins. By contrast, the open sea glittered with chinstraps. Until then nobody knew that Adélies depend on sea ice to get through the winter, feeding on krill around its edges. In recent years, as sea ice has become scarcer around Palmer, it became apparent why the region's Adélies were struggling while the chinstraps flourished.

But that's not the Adélies' only problem. By nature, Adélies are hard-wired for a narrow and inflexible range of behavior, as an anecdote from several winters ago illustrates. The icebreaker encountered perhaps 2,000 Adélies marching along single file. As the ship pulled even with the marchers, the lead bird reached a gap in the ice perhaps a foot across. It hesitated, hopped over, tripped on a small bump, fell flat on its face, popped up, and kept going. "Damned if every single penguin didn't jump at exactly the same place and do a face plant exactly like the first one," Fraser recalls. "Bam, bam, bam." Not one Adélie thought to cross just 5 inches to the left or right. "That says something about the intelligence of Adélies," Fraser said.

This is more than a humorous story to Fraser. It demonstrates that, even more than many other penguins, this species has evolved very inflexible habits. "That is a boon in a fragile and tough environment where, once one finds a good niche, it pays off to stick with it," Fraser explains. "But it is a behavioral flaw in times of climate change."

Creatures of habit. Around Palmer, he sees evidence on every visit to the rookeries of the Adélies' inability to adjust to surprises. The birds live a dozen years or longer and mate for life. Once a pair establishes a nesting site–most commonly on the same island where they were born and often in the same colony–the couple usually returns to the exact same nesting place year after year.

But warmer air holds more moisture, and in this still-cold place, that means more snow. Prevailing winds here pile snow deepest on the southwest-facing sides of the small islands where the penguins nest. The birds there seem incapable of recognizing, in the deepening snow, that it is time to set up housekeeping somewhere else. When spring arrives in September and October, the Adélies often–and stubbornly–pile pebbles atop snow 2 feet thick or more to build their nests. Later, frigid meltwater kills eggs and newborn chicks by the score. By contrast, chinstraps seem a bit more flexible in where they nest, choosing sites based more on their immediate suitability.

During a penguin-counting survey on Cormorant Island, Patterson points to a tiny remnant Adélie outpost. It has two nests, surrounded by a penumbra of smoothed pebbles where hundreds of penguins raised their young 10 years ago. And standing about insolently are half a dozen brown skuas, waiting for a chance to grab a lightly defended baby penguin. Maps of Adélie colonies consistently show that most of the failed colonies are located where snows have become deepest. The chicks born in these places are hatched later and are smaller. Chicks from colonies on northern-facing shores weigh an average of nearly 7 pounds; those on snowier south shores are a pound lighter. "Lightweight chicks won't survive their first winter," Fraser says.

Every failed penguin colony could be just one more local chapter in the pitiless pageant of nature. Certainly, there are no endangered species here. Adélies are flourishing at the southern end of their range in the Ross Sea. And that fits the climate-change model, too. The Ross Sea historically has been so bitterly cold that a little warming there makes it more, not less, hospitable to the Adélies. "Their whole range," Fraser observes, "seems to be shifting south."

But in most of the world, the natural ranges of species cannot move as easily as they can in this vast, unspoiled continent. If warmer weather drives a species to the edge of a city, or to the top of a mountain, that may be the end of it. And that's why the lessons from the Adélies here should demand attention elsewhere.

Palmer is one of several sites in the Long-Term Ecological Research program, sponsored by NSF to keep track of how wildlife in specific areas is doing. While Fraser has been there longest, other Palmer-based scientists track the richness of the bottom of the food chain, including marine algae and other plankton in the sea, the krill that feed on plankton, and microbes living in the water, ice, and thin soil.

Man with a plan. Temperature and snowfall are not the only changing environmental factors here, either. The famed ozone hole, a loss of ultraviolet-absorbing ozone molecules in the stratosphere over Antarctica, affects the Palmer area in October and November each year. Ultraviolet radiation levels soar. University of Texas graduate student Jarah Meador found so many bacteria living in the glacier fragments floating in the harbor that she E-mailed Wade Jeffrey of the University of West Florida, principal investigator on a program to monitor the effects of ultraviolet radiation on Antarctic microbes. He had a plan.

One sunny day, after some training in rappelling down ice cliffs with the base search-and-rescue team, Meador hiked up the glacier behind the base and lowered herself on a rope down a narrow crevasse that extended 100 feet into the ice. "It's great down there," she exulted on the way back out. In the deep blue light filtering through the ice, she dug into the vertical wall of ice at intervals, carefully preventing contamination while she gathered samples. If the microbes at great depth turn out to be different from those near the surface, it could mean that evolution is already retuning the microbes to tolerate increased levels of ultraviolet radiation.

No one yet knows how or whether the ozone hole is a major threat to the region's biology. But there is little doubt about warming and penguins. After a few decades watching the same population of birds–he is now studying great grandchicks of some of his first ones–Fraser says he is beginning to feel, in his bones, what he calls ecological time: the decades to centuries over which populations ebb, flow, and sometimes vanish. At one of the station's evening science seminars, physicist Dan Lubin of Scripps Institution of Oceanography, at Palmer to study how ice and open sea reflect sunlight, notes that climate change does not appear or disappear quickly. The atmosphere's carbon dioxide and other solar-energy-trapping gases won't return to preindustrial levels for 200 years or more, even if humans could somehow stop their emissions right now. "Two hundred years!" Fraser says. "Even in ecological time, that is enough to really screw things up."

As this account goes to press, Fraser reports by E-mail from Palmer that this year's chicks, so fuzzy and hapless in mid-January, have already changed into juvenile plumage and are going for their first swims. In a couple of weeks, if you can imagine this, the islands will be silent, as the penguins head out to sea for winter. And next year, he and Donna Patterson will be back to greet them when they return to raise another generation–and to count how many made it to another spring.