Emperor penguins could be headed toward extinction in at least part of their range before the end of the century, according to a recent study by Woods Hole Oceanographic Institution (WHOI).
Breeding pairs of Emperor Penguins may be reduced to 400 by the end of the century.
Breeding pairs of the Emperor penguin may fall to 400 by the end of the century.
If climate change continues to melt sea ice at the rates published in the latest Intergovernmental Panel on Climate Change (IPCC), the median population size of a large emperor penguin colony in Terre Adelie, Antarctica, likely will shrink from its present size of 3,000 to only 400 breeding pairs by the end of the century.
What’s more, the researchers calculate that the probability of a drastic decline (by 95 percent or more) is at least 40 percent and perhaps as much as 80 percent.  Such a decline would put the population at serious risk of extinction.
“The key to the analysis was deciding to focus not on average climate conditions, but on fluctuations that occasionally reduce the amount of available sea ice,” said Hal Caswell, a WHOI biologist and co-author of the study who is also noted for his work in mathematical ecology.
Sea ice plays a critical role in the Antarctic ecosystem – not only as a platform for penguins to breed, feed, and molt, but as a grazing ground for krill, tiny crustaceans that thrive on algae growing on the underside of the ice. Krill, in turn, are a food source for fish, seals, whales, and penguins.
One fluctuation and subsequent sea ice reduction in Terre Adelie during the 1970s led to a population decline in emperor penguins of about 50 percent.
The WHOI research raises several questions for Antarctic researchers and those interested in conservation of penguins. One is what the march of this population toward extinction tells us about the prospects for the emperor penguin throughout its range.
“This analysis focuses on a single population—that at Terre Adelie—because of the excellent data available for it,” Caswell said.  “But patterns of climate change and sea ice in the Antarctic are an area of intense research interest now. It remains to be seen how these changes will affect the entire species throughout Antarctica.”

Will they Adapt?

Yet another question is whether the penguins might adapt to changing conditions, perhaps by changing the timing of their breeding cycle. However, this does not seem to be happening.
“Unlike some other Antarctic bird species that have altered their life cycles, penguins don’t catch on so quickly,” said WHOI biologist Stephanie Jenouvrier, also co-author of the study. “They are long-lived organisms, so they adapt slowly. This is a problem because the climate is changing very fast.”
Like the Arctic in the Northern Hemisphere, Antarctica has been experiencing effects attributable to changes in regional climate. Future changes resulting from global climate change are expected to be significant in this region along with its Arctic counterpart.
Over the past half-century, there has been a marked warming trend in the Antarctic Peninsula. Much of the rest of Antarctica has cooled during the last 30 years, due to ozone depletion and other factors.  Surface waters of the Southern Ocean surrounding Antarctica have warmed and become less saline, and precipitation in this region has increased.
Antarctica has experienced significant retreat and collapse of ice shelves, the result of regional warming. The loss of these ice shelves has few direct impacts on sea level and global climate. Because the ice shelves were floating, their melting does not directly add to sea level rise. They usually are replaced by sea-ice cover, so overall albedo (reflectivity) changes very little.