Melting ice decimates emperor penguin chicks in Antarctica – 08/24/2023 – Environment

The survival of emperor penguins could be seriously threatened, according to a study that found catastrophic chick mortality in several colonies in Antarctica in 2022, as a result of early thaw caused by climate change.

Of the five colonies observed in the Bellingshausen Sea region of West Antarctica, four suffered 100% loss of pups. They drowned or died of cold as the ice gave way beneath them.

They were not yet mature enough to deal with the region’s harsh climatic conditions, explain the researchers in the study published this Thursday (24) in the journal Communications: Earth & Environment, from the Nature group.

“This is the first major reproductive failure of emperor penguins in multiple colonies at the same time, due to melting sea ice, and is likely a sign of things to come,” lead author Peter Fretwell told AFP. researcher for the British Antarctic Survey.

“We had predicted this for some time, but seeing it actually happen is scary,” he lamented.

During the spring of last year in the southern hemisphere, Antarctic sea ice, formed by the freezing of salty ocean water, reached record melting rates, before falling in February to its lowest level since satellite measurements began, 45 years ago.

This early thaw occurred in the middle of the species’ breeding season, which in itself was already complex and fragile.

These seabirds breed in winter, starting in June, when temperatures are more rigorous. The eggs hatch in September, before the arrival of spring, and the young reach their autonomy around January-February.

The population of emperor penguins, also known as Aptenodytes forstericonsisted of about 250,000 breeding pairs, all in Antarctica, according to a 2020 study.

Bellingshausen sea colonies represent less than 5% of this total. “But globally, 30% of all colonies were affected by the thaw last year, so there were many hatchlings that didn’t survive,” warns Fretwell.

Every year, starting in March, the adults embark on a journey of up to one hundred kilometers to reach the reproduction 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 go out in search of food, sometimes covering several hundred kilometers.

Males keep the eggs warm, balanced on their paws and covered in folds of skin that form an incubator pouch. All this without moving or eating, while waiting for the females to return.

Extinction by 2100?

This immutable ritual, portrayed in the French documentary “The March of the Penguins” (2005), suffers the effects of global warming.

Despite its ability to seek out alternative breeding sites, the melting records since 2016 threaten to exceed the species’ adaptive capabilities, scientists believe.

The emperor penguin was recently listed as an endangered species by the US Wildlife Authority.

In addition to the risk to their breeding grounds, the emperor penguin also suffers from ocean acidification, another effect of global warming, which threatens certain crustaceans on which it feeds.

The British Antarctic Survey estimates that, at the current rate of climate change, virtually all of this species could have disappeared by the end of the century.