Four out of five emperor penguin colonies in Antarctica’s Bellingshausen Sea experienced “total breeding failure” last year after the sea ice young chicks need to survive broke up earlier than usual.
Researchers with the British Antarctic Survey used satellite images to track sea ice and the presence of penguins on the ice. Their findings were published on Thursday in the journal Communications Earth & Environment.
“It’s a grim story,” lead study author Dr. Peter Fretwell told The Guardian. “I was shocked. It’s very hard to think of these cute fluffy chicks dying in large numbers.”
More than 9,000 chicks likely died in all, according to The Washington Post. Emperor penguins lay eggs in May or June, and the chicks hatch after 65 days. But it takes the young birds until December or January to develop waterproof feathers, meaning they must stay on solid ice before that. When the ice breaks up too early, the chicks can fall into the ocean and drown or freeze, according to the BBC.
The study notes that localized sea ice loss has caused chick deaths in the past, but such widespread “catastrophic breeding failure” is new and alarming.
“We have never seen emperor penguins fail to breed, at this scale, in a single season,” Fretwell told NBC News.
Cassandra Brooks, an Antarctica researcher and assistant professor at the University of Colorado Boulder who was not involved in the research, told CNN that the study adds to a growing pile of proof that human-caused climate change could easily be a death sentence for the birds.
“There is mounting evidence that emperor penguins may actually go extinct directly due to loss of sea ice resulting from our planet’s warming,” she said. “Our window in which to ensure their survival is narrowing.”