Scientists have warned that the annual process where Emperor penguins completely shed and regrow their feathers is putting the species in extreme peril as Antarctica is transformed by global warming.
The birds are reportedly more at risk from climate change than any other air-breathing Antarctic animal. Each year, these penguins must remain on platforms of floating ice for 30 to 40 days to replace their weather-beaten feathers with new, waterproof coats.
However, between 2022 and 2024, Antarctic sea ice shrank significantly due to climate change, depriving the birds of safe places to undergo this “catastrophic moult”.
Peter Fretwell of the British Antarctic Survey, who has tracked the animals for 20 years using satellite imagery, reported that most of the birds can no longer be found. Researchers fear that thousands of penguins may have frozen to death in icy waters because they lack their waterproof protection during the moult.
The research, published in the scientific journal Communications Earth & Environment, focuses on West Antarctica, an area home to 30-40% of the global Emperor penguin population. The moult is described as incredibly energy-intensive, with birds losing up to 50% of their body mass.
Fretwell identified the crisis after spotting large brown smudges in satellite pictures from 2019-2025, which turned out to be extensive mounds of feathers left behind in Marie Byrd Land.
While sea ice was relatively stable between 2019 and 2021, it fell from an average of 2.8 million sq km to a record low of 1.79 million sq km in 2023. Although there was a modest recovery in sea ice in West Antarctica by 2025, satellite pictures revealed only 25 groups of penguins where many more were expected.
Fretwell suggested that while some birds might have travelled to East Antarctica to moult, such a move would disrupt breeding and lead to further population losses.
The findings indicate that the effects of global warming can result in moments of dramatic, rather than slow, change.
Fretwell noted that the loss was not limited to just a few colonies and expressed concern that predicted extinction dates for the species might be moved forward from the end of the century.
Data regarding potential death tolls will be gathered from an imminent population count in the Ross Sea region.
For long-term survival, the birds may need to adapt by moulting on shallow ice shelves, though this could come at a cost to their traditional breeding and feeding patterns.
