Activists for the environmental group Greenpeace hang a banner from a smokestack in Porto Alegre, Brazil, Friday, February 1, 2002. The banner, depicting a thermometer with President Bush at the top, is to bring attention to global warming and the U.S. environmental policy, to participants in the five-day World Social Forum. (AP Photo/Douglas Engle)

The numbers of adelie penguins on the Antarctic peninsula – the most northerly part of the frozen continent – are falling as global warming takes hold. And experts predict that, as the climate change continues, they may abandon much of the 900-mile-long promontory altogether.

The archetypal "tuxedoed" species like the cold even more than other penguins. And the peninsula has been warming up faster than almost anywhere else on earth, with temperatures increasing at least five times faster than the world average. Scientists believe this is disrupting their food supplies.

Global warming is also causing them grief in another of their strongholds, the Ross Sea. Two giant icebergs have broken off the Antarctic ice sheet and are blocking the way from their breeding colonies to their feeding areas. As a result they have to walk 30 miles further to get food – no small matter when they can manage only one mile per hour. And, on the other side of the continent, thousands of emperor penguin chicks drowned near Britain's Halley base after the ice broke up early, before they had learned to swim.

Like miners' canaries, the dinner-jacketed penguins of Antarctica are providing an early warning of danger to come. For global warming is heating up the frozen continent faster than the rest of the world, and the penguins are among the first to feel the effects.

Flightless, and so unable to escape like other birds, they are affected by what happens both on land and sea. And, because they are easy to spot and count, they provide an early indication of what may be happening to other species.

They are feeling the heat most strongly on the Antarctic peninsula, which juts out from the polar land mass towards South America. Studies of air temperatures around the world over the past half-century suggest that this is one of the three areas on the planet – along with north-western North America and part of Siberia – warming up fastest. The British Antarctic Survey says flowering plants have spread rapidly in the area, glaciers are retreating, and seven huge ice sheets have melted away.

As the peninsula has warmed up, the numbers of adelie penguins have been dropping. Scientists suspect that the rising temperatures affect the small fish and other marine animals on which they feed, though they are not yet sure how.

Professor Steven Emslie, of the University of North Carolina, believes that if the warming goes on the penguins "would continue to decline in the peninsula, and may completely abandon much of it". Studies of fossilized remains that he has carried out near Britain's Rothera base show that the numbers of the penguins have sharply declined during warmer periods in prehistory.

On at least one occasion, the decline in the peninsula was marked by a rapid increase in the penguins in the Ross Sea more than 2,000 miles away. But in recent months global warming has been causing them trouble there too. Researchers for the US National Science Foundation said that one colony of adelies at Cape Royds will "fail totally" this year. And scientists at the Scripps Institute of Oceanography add that a colony of emperor penguins at Cape Crozier has also failed to raise any chicks.

Global warming also threatens the food supplies of emperor penguins. When there is less ice in the sea, populations of krill – a staple in their diet – fall.

Despite all this, penguins are not in danger of extinction; there are millions of them still in Antarctica and one species – the chinstrap penguin – seems to be thriving in the warmer weather. But they still provide a warning. In the words of the International Union for the Conservation of Nature, the world's leading conservation body: "Things happening to penguins are a foretaste of things to come."

© 2002 lndependent Digital (UK) Ltd

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