A group of scientists ensures that the survival of emperor penguins (Aptenodytes forsteri) could be in serious danger, after confirming a “catastrophic” mortality among the chicks of several colonies in Antarctica as a result of the early thaw caused by climate change, as detailed in a study published this Thursday by the journal Nature Communications Earth & Environment.
Of the 5 colonies observed in the Bellingshausen Sea region of West Antarctica, 4 suffered a “catastrophic” loss of 100% of their hatchlings, drowning or freezing to death when the ice gave way under them, as they were not yet mature enough to face the harsh climatic conditions of the region.
“This is the first major breeding failure of emperor penguins in multiple colonies at the same time, due to melting sea ice, and is likely a sign of what to expect in the future,” said study lead author Peter Fretwell, a researcher at the British Antarctic Survey.
“We already predicted it a while ago, but seeing how it occurs de facto is sinister,” he lamented.
A fragile species and threatened by the thaw
During the southern spring of last year, Antarctic sea ice, which is formed by the freezing of salty ocean water, had reached record melting rates, before falling in February to its lowest level since satellite measurements began 45 years ago. years.
That early thaw came right in the middle of the breeding season for that already complex and fragile species. These seabirds hatch in winter, starting in June, when temperatures are harsher. The eggs hatch in September before the arrival of spring and the young reach their autonomy around January-February.
A scenario that is repeated throughout Antarctica
The emperor penguin population was made up of about 250,000 breeding pairs, all in Antarctica, according to a 2020 study. Colonies in the Bellingshausen Sea represent less than 5% of that total, but “in the global count, 30% of all the colonies were affected by the snowmelt last year, so there will be a lot of chicks that didn’t survive,” Fretwell warned.
A ritual affected by global warming
Every March, the adults embark on a journey of up to more than one hundred kilometers to reach the breeding sites on the ice, which are always the same. The females lay a single egg and leave it in the care of the male while they search for food, even traveling hundreds of kilometers.
The males keep the eggs warm, balanced on their feet and covered with folds of skin that form a brood pouch. All this, without moving or eating, waiting for the females to return.
That immutable ritual, portrayed in the French documentary film “The March of the Emperor” (“The Emperor’s Journey” in Spain and “The March of the Penguins” in Latin America), suffers the effects of global warming.
The Emperor penguin was recently listed as an endangered species by the US Wildlife Protection Authority.
Despite their ability to search for alternative breeding sites, melting records since 2016 threaten to exceed their adaptive abilities, scientists believe. Beyond the danger of their breeding sites, the emperor penguin also suffers from ocean acidification, another effect of global warming, which threatens certain crustaceans on which it feeds.
He British Antarctic Survey estimates that, at the current rate of climate change, practically all of this species could have disappeared by the end of the century.
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