Emperor penguins are in danger of extinction, according to a new study, and Antarctica's population of 600,000 could diminish by about a fifth by the year 2100.

According to BBC News, researchers, whose study is published in the journal Nature Climate Change, said climate change and the resulting sea-ice loss in the Antarctic will be the leading cause. Researchers from the U.S., the Netherlands and Britain from different institutions collaborated on the study.

"Our research showing that colonies seem to appear and disappear throughout the years challenges behaviors we thought we understood about emperor penguins," study lead author Michelle LaRue, a researcher at the University of Minnesota College of Science and Engineering, said in a press release. "If we assume that these birds come back to the same locations every year, without fail, these new colonies we see on satellite images wouldn't make any sense. These birds didn't just appear out of thin air-they had to have come from somewhere else.

"This suggests that emperor penguins move among colonies. That means we need to revisit how we interpret population changes and the causes of those changes."

Sea ice loss is shortening Emperor Penguin's main supply of food, shrimp-like crustaceans in the Southern Ocean called krill. Since krill feed of algae in sea ice, the two are intertwined.

"Given this new research, and what we already know about global temperatures warming and the changing climate, one of the things we should do immediately is put a marine reserve in place so we can make sure that we are not fishing in areas where the penguins need to forage for food," Andrea Kavanagh, director of global penguin conservation for the Pew Charitable Trusts, told the Guardian. "It is one way of eliminating one more threat to the penguins."

Emperor Penguins were the subject of the documentary "March of the Penguins" and the animated film "Happy Feet" alike. The colony from the documentary, called Pointe Géologie, has been the subject of scientific study for more than 60 years.

"It's possible that birds have moved away from Pointe Géologie to these other spots and that means that maybe those banded birds didn't die," LaRue said. "If we want to accurately conserve the species, we really need to know the basics. We've just learned something unexpected, and we should rethink how we interpret colony fluctuations."