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What can dying penguins tell us about the future of the planet?

The night before arriving at Palmer, Bill gives me a briefing. Dr Bill Fraser is a seabird ecologist, one of an inner group of US scientists who have dedicated themselves to Antarctic research.

We sit squeezed between bags of kit in the small cabin he shares with his partner and co-worker, Donna Patterson. Finding a place to talk on the Gould isn't easy. Videos dominate the lounge; the bridge is cramped. People are ready to start work and haven't. Most are just passing the time, or feeling sick. But Bill can't stop. He has been in the field almost continually for over a year - last summer at Palmer, followed by a slug of winter cruises in the biologically rich Marguerite Bay area south of Palmer.

The news is shocking. The season, Bill says flatly, has gone to hell. Palmer's Adelie penguins are in crisis, barely holding on. The weather has been relentless, dire. The seabird work is under real pressure. "We are arriving to a catastrophe, walking into a bitter scenario produced by climate change," he says. "The Adelie penguins don't have the capacity to survive the drastic changes that are occurring. There's no doubt."

The real penguin losses in Antarctica are happening on the Antarctic Peninsula, where the greatest warming is occurring. Bill describes landing on the low, ice-enclosed Dion Islands during last winter's cruise in Marguerite Bay. In 1948, 21-year-old Bernard Stonehouse, surveying for the British with a husky team over dodgy sea ice, discovered an emperor penguin colony on the Dions, the furthest north these penguins breed.

Bill arrived at dawn one August morning. Washed pink sky, pearly grey ice, soft-focus light. He found just nine lonely pairs. Since Bernard made the first studies of an estimated 500 birds, the colony has been little visited. Outside influences can't be discounted. There can be no protective fences around vulnerable bird populations to exclude helicopters or passing yachts. But for Bill, the sight of those remnant pairs of emperors at a critical period of their brooding phase was deeply symbolic. "It was the saddest sight. They won't survive. They were the only known emperor penguin colony on the Antarctic Peninsula."

Each summer, beginning in October, the seabird team at Palmer record their data and observations. The focus is on the birds of Bill's patch, the Adelie penguins nesting on five inner islands and a few outer islands. Year after year Bill has worked to find out what affects the survival rate of the Palmer Adelies.

Bill: "Each season here at Palmer we do what we always do. Now ecology deals us a wild card: unprecedented snow. My penguins are in difficulties." But, ever the scientist: "In effect, a natural experiment is occurring. Hypotheses that have been in development for a long time are being tested. There will be measurable results by the end of February." This season will be different from anything ever recorded. I've got a lot to catch up on. Next morning, we slip in sideways to Antarctica.

Seeing for myself: 8 January 2007

The sun shone day after day, my first summer at Palmer, and the Adelies panted in temperatures around 0C. The ground was pinky brown, stained with the guano of thousands of penguin meals, the discarded remnants of hundreds of thousands of krill and small fish, each individually located in the ocean, caught in a penguin's beak, swallowed and transported back to the land.

Parents ran up from the water clean and shiny, and the stones on the ground clinked as they passed. At the nests the relieved partner left, dirty but duty done, pulling its body in tall and thin, flippers tucked close, weaving and swerving through the gauntlet of aggressive nest-sitters like a rugby player trying to avoid tackles. There's a revelling in the intense activity of a penguin summer. Its rhythm catches you up. It's there in all the accounts - the early explorers, scientists, delighted visitors, dedicated penguin observers, everyone engrossed in the privilege of watching, the luck of being there. Becoming in a small way part of it, because they are tolerated. Stop watching, and you miss something. Keep watching and you begin to recognise the stages.

But this time there is so little noise. So little smell. Such small groups. So few chicks. An almost complete absence of guano, that starburst of pink radiating out from each nest, that signal of occupancy, of chicks at home, of regular feeding, of the need to feed, of rotation of parents with their full bellies coming back from the ocean. Some of the smaller colonies have only one successful nest with one chick, very occasionally two, under the one bird. Seeing the Adelies for myself is shocking. In my head are memories of busy, functioning penguin colonies. The din of living, the pervasive smell of food being crammed in and processed out. Of beaks snapping and clashing, of the haze of dust and feathers rising over massed nests.

By the end of the first week in January 1999, nests were beginning to lose their discrete shapes, be trodden down, the carefully accumulated nest pebbles scattered. Woolly grey chicks were starting to wander. Some clustered in mini-crèches, long flippers hanging like oars, feet too big, like clowns' feet. Single penguins patrolled the edges of colonies, facing outwards, watchful, cocky. Skuas swooped, or strutted, bold, looking for opportunity. The cackling, calling, grunting, the insistent cheepings of chicks, the strong distinctive smell, filled the air.

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Now, at the same point, the end of the first week of January, most chicks are still very young, helpless, lying on their bellies. The colony outriders - those outward-facing singles - are hardly in evidence. Now there are so many singles, or penguins just standing around in twos and threes, it is difficult to understand if pairs really exist. Difficult to see if a nest is still in place or scattered, as in the crèching phase.

There is less aggression. Less need for a penguin to run the gauntlet to its nest. Less pecking, and flapping. Quieter, not hectic. Subdued. There seems a loss of structure. Colonies do not appear to be acting as a unit. There isn't a sense of a society engaged in group activity. Last time, each colony, each subset, seemed to me like a suburb, most households roughly similar. Now the rookery feels like an urban city in a war zone. Some colonies are reasonably active, some almost non-functioning. But in general the city is severely depleted. There appear to be very few "families", lots of singles and childless partners.

One leopard seal has been working the area periodically, another full-time. Pickings are easy at Torgersen, where birds have to stack in bottlenecks to come ashore. Beach access has been confined by snow to two narrow locations, and the water churns as a leopard thrashes a penguin out of its skin. Birds grab morsels. If the dead penguin is one of a functioning pair - this season that's not just a loss, it's a disaster.

There's a small amount of pebble-carrying and nest-tidying, but very little. I see one pair attempting a fumbling copulation: beaks clacking, flippers waving, male attempting to balance on the female's back. Many birds are sitting in the brooding position. But nothing is happening. What do birds do when the eggs have failed? Does the pair bonding remain? Does alternate feeding continue when there's no need to relieve each other on the nest? I find just one empty egg on a rock; but no eggshells. I see dead penguins on the ground, bones and sinew, but the carcasses could belong to last year, or the year before. The skuas seem particularly confident. Where have all the penguins gone?

In 1988, NSF chartered the MV Polar Duke to undertake one of the first Antarctic winter research cruises, surveying 581 square kilometres of the Scotia and Weddell Seas.

Bill was on board. He laughs - an announcement came over the ship's systems, "will all scientists, and" - pause - "biologists come to the bridge".

In the sea ice, the ship's spotlights picked out thousands of Adelie penguins standing and lying on the floes in the darkness. But chinstrap penguins were observed swimming by the thousand in open water. Adelies and chinstraps both eat mainly krill in their summer diets. Their general appearance and size are similar. They have broad ecological similarities. Yet here they were, occupying very different habitats in winter. Bill: "The sight was an absolute wake-up call. A major turning point in my thinking."

In Antarctica, penguins were considered "indicator species". The food chain involved was thought to be remarkably simple. Large animals at the top, such as whales and penguins, ate krill, the small shrimp-like Euphasia superba which fed on phytoplankton, the grass of the sea. The hypothesis was that, as krill-eaters, penguins could reveal if too many tons of krill were being hauled out of the southern seas by the proliferating Eastern European fisheries: declining numbers of penguins would indicate too much fishing. Research was being carried out on penguin numbers along the Antarctic Peninsula, focusing on the five inner-island Adelie study sites at Palmer and a mix of sites further north at King George Island in the South Shetland Islands, where Adelies, gentoos and chinstraps nested. Concerns about managing resources drove the research, as well as concerns about changing the ecosystem.

But there was also the whale population reduction hypothesis: not a krill deficit, but an abundance. So many krill-eating baleen whales had been hunted and killed since the 1920s that there must, it was argued, be a "krill surplus" now that hunting had declined. The problem was the figures. At King George Island, the data of American researchers Wayne and Susan Trivelpiece showed the numbers of chinstrap penguins increasing, while Adelie numbers seesawed. The chinstraps' range was expanding south down the western side of the Antarctic Peninsula. Abundant krill could account for the increase.

But Adelies were also krill eaters. And, at the Palmer study sites, Adelies were in decline. Their numbers had decreased from 15,202 breeding pairs in 1975, when the data set began. Bill: "Intuitively the numbers did not fit together. Hypothesis. Data. The two didn't mesh. Classic science. I had pieces of a puzzle floating around in my head. I had a bunch of numbers lined up into a graph and I didn't know what they meant."

Bill says his next insight came immediately after the 1988 Polar Duke winter cruise, at a symposium on Antarctic biology organised in Tasmania by the Scientific Committee on Antarctic Research (SCAR). Listening to data on population increases and decreases among various species provided a "quantum leap" in Bill's ability to understand. What if the winter habitat of Adelies and chinstraps was significant? The winter cruise had shown that Adelies were obligate inhabitants of sea ice. "Adelie numbers were decreasing, chinstraps increasing: were we seeing a change in the relative availability of the two species' habitat? If so, what was the mechanism for the change?'

Overwinter survival is crucial to penguins. Dead penguins can't come back to breed. Underweight penguins with insufficient blubber insulation cannot sustain the brooding fasts. Overwinter survival, to use scientist-speak, can play a key role in driving long-term populations. Central to Bill's argument was the quantity and extent of sea ice. Had it changed? Was it reducing?

3 february, Litchfield Island

There are no sounds but the wash of the sea, the occasional calls of skuas. Every penguin is gone. The nests are abandoned. Listen to the silence. The silence of absence. The sound of failure.

Bill stands tall, still, on the carefully sorted pebbles. Standing where it should not be possible to stand, in the centre of a penguin colony, in the middle of summer. This season, on Litchfield Island, only seven pairs of penguins managed to keep eggs until hatching. Eighteen days ago, Bill counted four pairs of penguins in one colony, one pair in another. Five days ago, seven penguins remained. This space was still theirs. Now they have gone. The sound of extinction is approaching. In two to three years, Bill says, Litchfield will be vacant.

The map drawn in 1957 at Base N, showing the locations of local bird colonies, marks six Adelie colonies on the south-east peninsula of Litchfield. When Bill first arrived at Palmer in 1975, those colonies were extinct; 884 breeding pairs of Adelies were nesting further to the west, but still in the shadow of the high central hills, still on the island's southern slopes. With temperature change, with increased snow, the sites proved lethal. Storms tracking west to east between South America and the peninsula scoured snow from north-facing surfaces and dumped it in the lee. Penguin numbers fell rapidly.

Here is climate change in action, Antarctica as a living experiment. Litchfield Island is a precisely located landscape, with just two key species, Adelies and brown skuas. Their relationship is straightforward; the numbers have been collected. Contributing factors have been unpacked and understood, decline tracked over time. The hypothesis is clear, the outcome predicted.

Data from Litchfield had already revealed that, whenever an Adelie colony dropped below a certain number, the chicks were vulnerable to predation by brown skuas. Litchfield has six brown skua pairs. They are birds with long histories, many of them tracked.

As the population declined, they destroyed their meal table. This season, Litchfield's Adelie penguins failed to hatch chicks and so failed to deliver brown skua meals. This season, Litchfield's brown skuas fed until there were no Adelie eggs left, and no chicks. Nothing. Bill needed proof. Now he has it.

Shifting weather patterns challenge the precisely balanced interconnectedness of living things, their dependence on established networks to find food, to reproduce - to survive. Litchfield is an indisputable case study of the impact.

Antarctica is original planet. It's what draws me back, the noise stripped away, the challenge to see, think, feel, in this uncluttered place. But it is Antarctica's starkness, this freedom from the complexity of much of the world, that gives it crucial advantages for scientists, as a place to study climate change. No cities, no agricultural practices, no highways, or change of land use.

Here, the physical environment is not relegated and regulated. The ecological networks, the food chains, are relatively straightforward, comparatively simple systems far from the confusing signals of most of the rest of the world. The requirement on every living thing continually to negotiate temporary occupancy, to manage the complex interplay of climate and place, is palpable.

Living things flourish where they can, while they can. Salutary reminders for us humans, cocooned by urban living, lulled into assuming we can somehow ignore, or forget, the changeability and vulnerability of the thin layer of planet we use, the tiny, damp, curved space we happen to occupy at a pleasantly warm moment. Here on the Antarctic Peninsula, impacts of warming can be tracked. It's a clear, stripped-down preview of what could occur elsewhere. It's an unpacking of the ways climate change can reveal itself. It's a prologue to the way climate change can happen. At Palmer, this ferocious summer, we do not know the mechanisms delivering this weather, or how the weather relates to the peninsula's warming. But I can document what it means to be here.

Public perceptions of climate change have tumbled and eddied and swept forward, like branches carried by a river in a flood. Some have got stuck on snags or accreted detritus, but enough have travelled swiftly with the rushing water for an increasing acceptance. Our planet is irrefutably warming. No doubts, no buts. What has to matter is the climate, now, at this precise moment, with the living load our planet is currently carrying. And the speed of change. How fast.

Richard Alley, US polar geoscientist, speaking at the International Glaciological Society Symposium in Cambridge, August 2006: If you push too hard at the climate, something flips. People want to know. What does the future hold? When do we get in trouble? Everyone wants answers. They want predictions. We can't predict. But we can look at what will help us predict. Understanding ice, and measuring the mass balance of the ice sheets. With concentrated research effort we can do these things. That will tell us what will happen, and why.

The ice matters. For a long time I've been listening to ecologists, climatologists, meteorologists, geologists, oceanographers, palaeobiologists, palaeontologists; now, at this Cambridge symposium, I'm surrounded by people who are driven by ice - who study ice shelves, sea ice, glaciers, ice sheets, ice cores, frozen ground.

The ones who work on the Antarctic Peninsula accept my description of the ferocious summer for the infamous season of 2001-02. The ferocious summer was like a river violently flooding. It permanently changed the river bed. It changed the country. A one-off - but it could happen again on the peninsula. It nearly did in 2004-05. A blocking high got established, then it broke up.

What has happened is that the frequencies have shifted.

To Richard Alley, sea levels have risen in the past. People dealt with them. We as humans can respond, effectively. And he pulled up a powerful image from deep in our cultures. God, according to the Bible, sent a rainbow to promise man that he would never again allow Earth to be flooded.

But I think of Palmer, in the ferocious summer. Rising temperatures sent a rare rainbow. A potent symbol, but potent in a different way. In high latitudes, water comes from the sky packaged as frozen crystals, and stays frozen, as ice and snow. With increasing warmth, water gets delivered in liquid form, destabilising ice and snow and living things. As was happening at Palmer in 2001-02, that ferocious summer of rapid climate change. Perhaps the biblical rainbow isn't a promise. It is a reminder.

This is an edited extract from The Ferocious Summer: Palmer's penguins and the warnings of Antarctica by Meredith Hooper (Profile).

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