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Environmental researchers say half to three-quarters of the Antarctic's major penguin colonies face decline or disappearance if global temperatures climb more than 2C.
American researcher David Ainley, who has written a report on the fate of Antarctic penguins when global warming rises 2C above pre-industrial levels, has described the Adelie population as a bellwether of polar climate change.
He said aerial censuses taken by Landcare Research have shown their colonies increasing dramatically in the Ross Sea area, while colonies are declining around the Antarctic Peninsula, where sea-ice has been melting rapidly.
Climate change has left a continuous blast of warm air from the north eroding the sea ice across the Antarctic Peninsula.
On the northwestern coast of the peninsula, where warming has been the most dramatic, populations of Adelie penguins have dropped by 65 per cent over the past 25 years, as food has become scarce with the disappearance of sea ice.
Warmer temperatures mean that the atmosphere can hold more moisture, which in turn brings more snow, reducing the areas of ice-free land Adelie penguins need to raise their young.
The world's biggest Adelie colony is at Cape Adare at the mouth of the Ross Sea, within a few hundred kilometres of Scott Base.
Dr Ainley has led research being used by the WWF environmental lobby, which yesterday launched a campaign, 2C is Too Much.
Juan Casavelos, WWF's Antarctic climate change co-ordinator, said penguins are very well adapted to living in the cold and extreme conditions of Antarctica, "so the continued increase in global temperature and resulting loss of feeding areas and nesting zones for their chicks has already led to notable reductions in their populations".
"If temperatures increase by another two degrees these icons of the Antarctic will be seriously threatened."
Many recent climate models forecast likely temperature rises in excess of this and say a 2C rise above pre-industrial level could be a reality in less than 40 years.
Fossil penguin remains on the Antarctic Peninsula have shown that in ancient periods of climate warming, Adelie penguin numbers have fallen.
WWF said at the World Conservation Congress in Barcelona, Spain, that the only way to significantly reduce the risks of climate change in Antarctica, as well as globally, was to substantially reduce greenhouse gas emissions. It wants all nations to agree on a new global deal that will succeed the Kyoto Protocol and tackle climate change beyond 2012, with an obligation on developed countries to cut 25-40 per cent of their emissions by 2020 and 80-90 per cent by 2050, compared to 1990 levels.
The environmental lobby has also called for a network of marine protected areas to reduce pressure on fish species, and precautionary management measures that ensure the future of the krill and finfish fisheries and all Southern Ocean species - including penguins - that are dependent on them.
- NZPA
