"Global Warning: Brutal lessons from an Antarctic summer"

by Meredith Hooper - extract from The Ferocious Summer: Palmer's penguins and the warnings of Antarctica

January 2002

...The news is shocking. The season, Bill says flatly, has gone to hell. Palmer's Adélie 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 Adélie 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."

...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 Adélie study sites at Palmer and a mix of sites further north at King George Island in the South Shetland Islands, where Adélies, 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 Adélie numbers seesawed. The chinstraps' range was expanding south down the western side of the Antarctic Peninsula. Abundant krill could account for the increase.

But Adélies were also krill eaters. And, at the Palmer study sites, Adélies were in decline. Their numbers had decreased from 15,202 breeding pairs in 1975, when the data set began...

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 Adélie colonies on the south-east peninsula of Litchfield. When Bill first arrived at Palmer in 1975, those colonies were extinct; 884 breeding pairs of Adélies 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, Adélies and brown skuas...

Data from Litchfield had already revealed that, whenever an Adélie 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 Adélie penguins failed to hatch chicks and so failed to deliver brown skua meals. This season, Litchfield's brown skuas fed until there were no Adélie 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...

Here on the Antarctic Peninsula, impacts of warming can be tracked. It's a clear, stripped-down preview of what could occur elsewhere...