Penguin population may be halved by end of century

There will be far fewer penguins in Antarctica by the end of the century as a result of rising temperatures, according to a recent study.

Researchers at the University of Delaware say about 60 percent of Adélie penguin colonies will be in decline by 2099, though several areas of relatively unaltered climate on the continent may eventually become refuges for the animals over the next several decades.

The penguins breed around the entire continent, but are already experiencing declines in areas that have been more affected by changes to temperature, such as the West Antarctic Peninsula, one of the most rapidly warming places on Earth.

Climate has affected where the penguins live and breed, and when, with the geologic record showing that as glaciers expanded to cover breeding habitats with ice, colonies were abandoned, but when glaciers melted during warmer periods, they were able to return.

There is a limit to how much warming the penguins can withstand, however, which will likely influence them to abandon many of the places they currently occupy. Although the researchers say parts of the continent which appear to have once been home to the penguins could again offer them refuge, the population will still be affected negatively because of quickly shifting climate.

“Our study used massive amounts of data to run habitat suitability models,” Dr. Megan Cimino, a scholar at Scripps Institute of Oceanography, said in a press release. “From other studies that used actual ground counts — people going and physically counting penguins — and from high resolution satellite imagery, we have global estimates of Adélie penguin breeding locations, meaning where they are present and where they are absent, throughout the entire Southern Ocean. We also have estimates of population size and how their populations have changed over last few decades.”

For the study, published in the journal Scientific Reports, researchers combined penguin counts with satellite information and climate projections of sea surface temperature and sea ice, to predict habitat suitability for the penguins.

Overall, the researchers estimate about 30 percent of penguin colonies will be in decline by 2060 and about 60 percent will be in decline by 2099.

Particularly useful was data on warmer periods collected between 1981 and 2010, which, combined with satellite images, helped determine regions most suitable for penguin colonies. Areas such as the Cape Adare region of the Ross Sea, home to the earliest known penguin occupation, could be an area the animals end up, based on its current and predicted temperatures.

“Studies like this are important because they focus our attention on areas where a species is most vulnerable to change,” Cimino said. “The results can be used for management; they can have implications for other species that live in the area and for other ecosystem processes.”