‘Catastrophic breeding failure’ for penguins as Antarctic sea ice vanishes

  • Researchers found that a lack of sea ice around Antarctica’s Bellingshausen Sea led to “unprecedented” breeding failure in four of five emperor penguin colonies.
  • Sea ice cover in Antarctica has been experiencing record lows, which could spell disaster for the future of this iconic Antarctic species.
  • Previous estimates have suggested that if current rates of global warming persist, more than 90% of emperor penguin colonies would be “quasi-extinct by the end of the century.”

Emperor penguins in the Antarctic are suffering a “catastrophic” breeding failure as the region’s sea ice vanishes, pointing to a grim future for a species highly susceptible to the impacts of climate, a new study has found.

Researchers used satellite imagery to find that chicks in four out of five emperor penguin (Aptenodytes forsteri) colonies in the Bellingshausen Sea, an area along the west side of the Antarctic Peninsula, didn’t survive to fledge in the Southern Hemisphere spring of 2022. This lack of fledgling success is directly attributed to sea ice loss, which is a consequence of human-induced climate change, according to the study published in Communications Earth & Environment.

Emperor penguin colonies require sea ice attached to solid land between April and January to breed, molt and forage successfully. Any changes to the sea ice can lead to penguin chicks missing the opportunity to develop the waterproof feathers necessary for survival.

The researchers monitored the presence of emperor penguins between 2018 and 2022 at five colonies around the Bellingshausen Sea: on Rothschild Island, Verdi Inlet, Smyley Island, Bryan Coast, and Pfrogner Point. During the species’ breeding season in 2022, satellite imagery showed broken-up sea ice and no presence of penguins.

Scientists estimate that if current rates of global warming persist, more than 90% of emperor penguin colonies would be “quasi-extinct by the end of the century.” Image by Acaro via Wikimedia Commons (CC BY-SA 3.0).

Sea ice cover in Antarctica has been experiencing record lows, even now, during the current winter season when sea ice was expected to build back up.

During the penguin breeding season in 2022, parts of the central and eastern Bellingshausen Sea region had 100% sea ice loss, making it very unlikely that emperor penguin chicks would survive.

“We have never seen emperor penguins fail to breed, at this scale, in a single season,” study lead author Peter Fretwell, a scientist at the British Antarctic Survey, said in a statement. “The loss of sea ice in this region during the Antarctic summer made it very unlikely that displaced chicks would survive.”

Fretwell said he and his colleagues have continued their research since publishing their study and found that “19 colonies around Antarctica were affected by early sea ice break up last year.”

“At present we do not know how many chicks from these colonies have perished in total, but 19 colonies is around 30% of the total number of colonies,” he told Mongabay in an email. “We believe this is a sign of things to come — we have been predicting it for a while, and now our fears are starting to play out. The data from last year, 2022, was very bad, but the winter sea ice at present this year is much worse. At many colonies, including those in the Bellingshausen Sea the sea ice formed very late, so it looks inevitable that breeding success this year will be just as bad if not worse, both in the Bellingshausen and across Antarctica.

“The fact that the sea ice was lost from a whole region, rather than from individual colonies was unprecedented,” he added.

Previous estimates have suggested that if current rates of global warming persist, more than 90% of emperor penguin colonies would be “quasi-extinct by the end of the century,” the study notes.

Sea ice cover in Antarctica has been experiencing record lows. Image courtesy of Whitley Fund for Nature.

Michelle LaRue, a penguin expert at the University of Canterbury in New Zealand, who was not involved in the study, said the five researched colonies are “fairly small” and that last year’s breeding failure will likely have “little impact on the overall population of emperor penguins.”

“Early breakup of sea ice at colonies is not uncommon (this happened in Halley Bay in 2016, Cape Crozier in 2018, for example), so we could expect that the adult birds there can probably deal with the loss and try again the following year,” LaRue told Mongabay in an email. “They are pretty resilient animals due to their living in a notoriously extreme place … and so it’s likely they are able to simply hang in there.

“However, I have not yet seen that many locations fail in a single year due to early breakup of sea ice,” LaRue added. “Further, the sea ice in the Southern Ocean is again at a record low this year, so that is a worry.”

Penguin expert Pablo Garcia Borboroglu, founder of the Global Penguin Society, who was also not involved in this research, said this evidence of climate change’s impact on emperor penguins was “stark.”

“This dire situation aligns with the concerning fact that half of the 18 penguin species are now considered threatened on the IUCN Red List,” Borboroglu told Mongabay in an email. “This study underscores the vulnerability of penguins to the effects of climate change, particularly Emperor penguins, and serves as a grim reminder that immediate action is needed to address the escalating consequences of global warming.”

Banner image caption: Emperor penguins need intact sea ice until the chicks are ready to leave their nesting grounds. Image by Christopher Michel via Flickr (CC BY 2.0).

Elizabeth Claire Albertsis a senior staff writer for Mongabay. Follow her on Twitter@ECAlberts.

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Fretwell, P. T., Boutet, A., & Ratcliffe, N. (2023). Record low 2022 Antarctic sea ice led to catastrophic breeding failure of emperor penguins. Communications Earth & Environment, 4(273). doi:10.1038/s43247-023-00927-x