King penguins have evolved to live where few animals can. But now, warming waters are posing a threat to the species' survival. As an international team of researchers reports in the journal Nature Climate Change [PDF], rising global temperatures could eradicate 70 percent of the King penguin population by 2100.

Most of the 3.2 million King penguins alive today are settled in the ring of ocean between 45° and 55° south known as the Antarctic Polar Front. This region is a sweet spot for these penguins: It's where cold Antarctic waters collide with and slip beneath the warmer waters from higher latitudes, creating the perfect temperatures and salinity to support marine life. King penguins make camp on the islands dotting this belt and hunt for krill and fish in the surrounding sea.

But that abundant food source won't remain in the penguins' neighborhood for much longer. The study authors report that human-caused climate change is pushing the Antarctic Polar Front further south, creating a gap between the islands the penguins call home and the life-supporting waters they depend on for survival.

King penguins accomplish some incredible things to get a meal. Like other penguins, the couples will take turns caring for their young, with one parent waiting on land without food for several days and the other swimming hundreds of miles roundtrip gathering nourishment for the whole family. But as the Antarctic Polar Front drifts away from established penguin colonies, penguins will have to swim farther for their food, and parents and offspring will have to wait longer to eat, with many eventually starving to death.

By 2100 the islands with the biggest King penguin populations will have become uninhabitable, spurring the deaths of 1.1 million breeding pairs, about 70 percent of the species, unless they move elsewhere.

In order to survive, the threatened birds must find new islands that are ice-free with smooth sand or pebble beaches and that hover at temperatures around 32°F year-round, all while staying close to their migrating food source. Such habitats aren't be impossible to find, and King penguins have adapted in the face of dramatic climate shifts in the past. But unless swift action is taken towards fighting climate change, penguin numbers are on track to take a massive hit in the coming decades.