for National Geographic News
Up to 75 percent of major Antarctic penguin colonies may disappear if climate change continues to heat up the continent, according to a recent report.
A global temperature increase of 3.6 Fahrenheit (2 degrees Celsius) above pre-industrial levels will result in widespread changes to sea ice that the birds depend on for survival.
The temperature increase will, in any scenario, lead to a major reshuffling of colonies of emperor and Adélie penguins—the two penguin species that rely on ice for hunting and breeding.
In addition, there could be marked habitat loss of these iconic birds, said the report commissioned by the conservation group WWF.
The penguins' range is already shrinking, said David Ainley, a penguin expert with H.T. Harvey & Associates of San Jose, California, who co-authored the report.
Up to 50 percent of emperor colonies and 75 percent of Adélie colonies could be affected, the researchers said.
(Related: "Adélie Penguins Extinct in a Decade in Some Areas?" [December 28, 2007].)
Antarctica currently has about 40 emperor colonies and 160 Adélie colonies, with each population containing thousands of birds.
Many scientists consider 3.6 degrees Fahrenheit (2 degrees Celsius) to be the minimum temperature increase necessary to trigger catastrophic climate change.
"If you go beyond 2 degrees it really gets scary," Ainley said.
According to the latest report by the U.N.'s Intergovernmental Panel on Climate Change (IPCC), released in February 2007, that threshold could be reached in as little as 40 years.
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