Global warming may doom emperor penguins to extinction
mongabay.comJanuary 27, 2009
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Combining population data from the Terre Adelie emperor penguin colony of eastern Antarctica from 1962-2005 and sea ice projections based on the latest IPCC Fourth Assessment Report, Hal Caswell and colleagues found a 36 percent likelihood of a 95 percent or more population decline by the year 2100. Emperor penguins are already suffering from warming, which has reduced the availability of prey and may have contributed to a halving of the colony size since the 1970s, but the new research focuses on changes in their habitat: sea ice. Emperor penguins are dependent on sea ice for breeding, feeding, and molting.
"Sea ice is a key breeding and feeding habitat for emperor penguins," write the authors. "Colonies are formed on sea ice many kilometers from the open sea, and breeding emperors make foraging trips between the colony and areas of open water during the entire incubation and chick rearing periods."
 Emperor penguin with chick. Photo courtesy of Samuel Blanc. |
Large-scale loss of sea ice will impair the ability of emperor penguins to survive in eastern Antarctica and the birds will have to adapt "by arriving at the breeding colony earlier, laying eggs earlier, or migrating" to avoid extinction. The researchers caution that while "Antarctic bird species that have altered their life cycles, emperor penguins have historically seemed slow to change".
"Given the future projected increases in greenhouse gases and its effect on Antarctic climate, evolution or migration seem unlikely for such long lived species at the remote southern end of the Earth," they write.
CITATION: Stephanie Jenouvrier, Hal Caswell, Christophe Barbraud, Marika Holland, Julienne Stroeve, and Henri Weimerskirch. Demographic models and IPCC climate projections predict the decline of an emperor penguin population. PNAS Early Edition for the week of January 26, 2009. www.pnas.orgcgidoi10.1073pnas.0806638106
