Climate has influenced the distribution patterns of Adélie penguins across Antarctica for millions of years. The geologic record tells us that as glaciers expanded and covered Adélie breeding habitats with ice, penguins in the region abandoned their colonies. When the glaciers melted during warming periods, the Adélie penguins were able to return to their rocky breeding grounds.Now, a NASA-funded study by University of Delaware scientists and colleagues at other institutions reports that this warming may no longer be beneficial for Adélie penguins. In a paper published June 29 in the journal Scientific Reports, the researchers project that approximately 30 percent of current Adélie colonies may be in decline by 2060, and approximately 60 percent of the present population might be dwindling by 2099. They also found the penguins at more southerly sites in Antarctica may be less affected by climate change.