Antarctic sea ice loss poses an existential threat to emperor penguins Stephanie Jenouvrier - WHOI

Unchecked climate change could drive emperor penguins to extinction by the end of the century as sea ice vanishes. But if the world delivers on the toughest target of the Paris climate agreement, of limiting global temperature rises to 1.5°C, then numbers of the iconic species will decline by less than a third.

Stephanie Jenouvrier at the Woods Hole Oceanographic Institution in Massachusetts found that the future of emperor penguins hinges on international climate efforts rather than their ability to adapt and move to new homes.

“Penguins are this indicator species, this canary in the coal mine, they are warning us of the future effect of climate. The big message is we need to listen to the penguins, and implement policies to meet the Paris agreement’s objective, and we need to do that now,” she says.


Marvel at glaciers, icebergs and ice floesOn a New Scientist Discovery cruise of the Antarctic

Disappearing sea ice affects emperor penguins directly because they rely on it for their nine-month breeding season, as well as a place to moult and escape from predators. But the ice is also crucial for the species because it influences the food they rely on, including krill.

Sea ice changes are already affecting emperor penguins, with breeding failures for three years in a row at their second biggest colony in the Antarctic pinned on early break-up of ice used for breeding.

Bleak outlook

To examine the fate of the world’s estimated 595,000 emperors as the planet warms, Jenouvrier and her colleagues modelled future colonies and populations under three different scenarios: hitting the Paris deal’s top target of 1.5°C, its minimum goal of no more than 2°C, and what would happen if emissions keep rising as they are today.

They combined a global climate model, sea ice projections and different scenarios of how the penguins might disperse, something most studies don’t look at. The result was an 81 to 86 per cent fall in population by 2100 under the business-as-usual scenario, depending on how the animals disperse to new homes.



“For me, the population is going to be extinct,” says Jenouvrier of such an outcome. Such a big decline would leave so few individuals that in ecological terms it would be considered an extinction, she says.

By contrast, warming of 1.5°C would see a 31 per cent decline, and 2°C a 44 per cent decrease.

The predicted penguin losses are worse than when Jenouvrier estimated them five years ago, partly because of better climate models since then.

Peter Fretwell at the British Antarctic Survey, who wasn’t involved in the study, says there is still a lot of uncertainty as to how emperors will react as the world warms, but their future looks bleak if emissions aren’t cut rapidly. “The difference between a scenario where we do halt global warming and one where we don’t is stark.”

Journal reference: Global Change Biology, DOI: 10.1111/gcb.14864