These two iconic polar species have been driven to endangered status by a warming planet

Climate change is pushing two iconic Antarctic species toward the brink of extinction — the emperor penguin and the Antarctic fur seal, a new assessment finds. The new listings, published Wednesday by the International Union for the Conservation of Nature, cite factors such as warming ocean waters, melting sea ice and declining availability of food to sustain such species.

The IUCN Red List of at-risk species is an authoritative census of species most at peril, as well as the causes of their decline. It is separate from classifications under the U.S. Endangered Species Act, which listed the emperor penguin as “threatened” in 2022. The Antarctic fur seal is not currently listed under ESA classifications.

Both species are highly charismatic megafauna. The emperor penguin is the largest of all penguin species, reaching upwards of 3 feet in height and 100 pounds in weight. These birds — and their huge, fluffy feathered babies — were featured prominently in the classic March of the Penguins documentary. The fur seals, in contrast, are the smallest of the Antarctic seal species and live primarily on sub-Antarctic islands. They were hunted nearly to extinction in the 19th century, but legal intervention and conservation projects had brought them back. Now, they’re in danger again.

The emperor penguin is moving from “Near Threatened” to “Endangered” on the IUCN Red List, based on new projections that its population will be cut in half by the 2080s. Satellite data show that emperor penguins lost about 10% of their population between 2009 and 2018, totaling a loss of more than 20,000 adult penguins.

The main factor that is driving populations down is climate change-related early breakup and losses of sea ice, said Philip Trathan, a member of the IUCN working group that completed the penguin Red List assessment.

“For emperor penguins, sea ice is their primary habitat,” Trathan told CNN. “They breed on fast ice,” which is sea ice connected to the coastline. “They molt on fast ice or on ice floes. They feed within the sea ice in polynyas, leads and cracks in the ice.”

“As sea ice decreases, their habitat also decreases,” Trathan said. “Major sea ice loss resulting from regional climate change remains an ongoing threat and will likely reduce breeding success and adult survival in the long-term.”

Seasonal sea ice in the Antarctic has significantly declined since 2016, he said, which has led to increased or even complete breeding failure in nearly half of the known colonies of emperor penguins throughout Antarctica.

Trathan said there are two threads of evidence that helped establish the emperor penguins’ status change: satellite image analyses supported by assessments completed on the ground, as well as population model assessments.

As for the Antarctic fur seal, its status is being moved from “Least Concern” to “Endangered” on the IUCN Red List after its population shrank by more than 50 percent between 1999 and 2025. The seals’ population decline is also tied to climate change, the IUCN found, which is reducing the availability of krill, their main food source.

Kit Kovacs, who worked on the Antarctic fur seal assessment, told CNN that as surface water temperatures close to Antarctica increase, krill is going farther offshore and into deeper waters to get to colder areas. “This makes the krill much less accessible to land-based krill predators,” Kovacs said.

“These new listings in the South Atlantic Ocean mirror changes that have already taken place in the North Atlantic Arctic where hooded seals, harp seals and ringed seals have already been shown to be in serious decline,” Kovacs said.

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