Emporer penguins face extinction

BBC NEWS

Less ice could spell bad news for a great many species

Emperor penguins, whose long treks across Antarctic ice to mate have been immortalised by Hollywood, are heading towards extinction, scientists say.

Based on predictions of sea ice extent from climate change models, the penguins are likely to see their numbers plummet by 95% by 2100.

That level of decline could wreak havoc on the delicate Antarctic food chain.

The research is published in the journal Proceedings of the National Academy of Sciences.

Emperor penguins, the largest species, are unique in that they are the only penguins that breed during the harsh Antarctic winters.

Colonies gather far inland after long treks across sea ice, where the females lay just one egg that is tended by the male. That means that the ice plays a major role in their overall breeding success.

What is more, the extent of sea ice cover influences the abundance of krill and the fish species that eat them - both food sources for the penguins.

Hal Caswell of the Woods Hole Oceanographic Institute and his colleagues used projections of sea ice coverage from the Intergovernmental Panel on Climate Change's (IPCC) last report.

In addition, they used a "population dynamics" model describing the mating patterns and breeding success of emperor penguins.

The model has been honed using 43 years' worth of observations of an emperor colony in Antarctica's Terre Adelie.

Slow learners

While there are a number of models and scenarios in the IPCC report, the team used only 10 of them - those that fit with existing satellite data on sea ice.

They then ran 1,000 simulations of penguin population growth or decline under each of those 10 climate scenarios.

The results suggest that by the year 2100, emperor penguins in the region are likely to experience a reduction in their numbers by 95% or more.

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