'This colony was once much larger,' Fen Montaigne says, 'but in recent years all the Adélie colonies in the northwestern Antarctic Peninsula have been in steep decline as soaring temperatures have made the environment inhospitable for the ice-dependent Adélies.' Researchers estimate that the population of Adélie penguins has declined by 65 percent over the past 25 years. Fen Montaigne / treehugger.com

By David DeFranza, Washington, DC
on January 6, 2011 Between 2005 and 2006, author Fen Montaigne traveled to Antarctica with Fraser to observe the life cycle of the penguins. “This colony was once much larger,” Montaigne says, “but in recent years all the Adélie colonies in the northwestern Antarctic Peninsula have been in steep decline as soaring temperatures have made the environment inhospitable for the ice-dependent Adélies.” In fact, researchers estimate that the population of Adélie penguins has declined by 65 percent over the past 25 years. The main problem is the Antarctic’s melting sea ice. Though the penguins breed on dry land, they need sea ice to hunt for food. And, though some models indicate that it is unlikely all of the ice in Antarctica will melt, the pace of glacier recession has accelerated in the last decade. “Average winter temperatures” in the region, Montaigne says, “have risen 11 degrees in 60 years.” The research done by Bill Fraser, seen here, has, Montaigne explains, “demonstrated that declining sea ice, which now covers the Southern Ocean off the western Antarctic Peninsula three fewer months a year than in 1979, is a major cause of Adélie declines.” The impact of the penguin’s shrinking population is nowhere more obvious than on Litchfield Island. “Adélies had bred on Litchfield for at least 500 years and numbered roughly 900 pairs 35 years ago,” Montaigne says, “but in the summer of 2005-2006, the last Adélie colony on Litchfield went extinct. In Fraser’s study area, which comprises seven islands spread over 15 miles, Adélie penguin populations have plummeted from roughly 30,000 to 35,000 breeding pairs in 1975 to about 5,000 today.”

The Trials and Tribulations of Adélie Penguins in a Rapidly Warming Antarctic (Slideshow)