“If sea ice declines at the rates projected by the IPCC climate models, and continues to influence Emperor penguins as it did in the second half of the 20th century in Terre Adélie, at least two-thirds of the colonies are projected to have declined by greater than 50 percent from their current size by 2100,” said study author Jenouvrier. Photo by Peter Kimball, Woods Hole Oceanographic; used with permission.

All 45 known emperor penguins colonies in Antarctica could be in decline by the centur...