Emperor penguin chicks victims of record melting of Antarctic sea ice for the second year in a row

Fourteen of Antarctica’s 66 penguin colonies were affected by early melting in 2023, according to a census by the British Antarctic Survey observatory.

Several colonies of emperor penguins have again seen their chicks perish in 2023, due to the record melting of the Antarctic sea ice linked to global warming, reveals a study published Thursday April 25 in the Journal of Antarctic Science. The record decline in sea ice in 2023 contributed to the second worst year of chick mortality since observations began in 2018, according to the British Antarctic Survey observatory’s census. This new observation follows the“catastrophic reproductive failure” in 2022, and threatens to reduce the population in the long term, Peter Fretwell, author of the study, told AFP.

These birds breed on pack ice, formed by freezing salty ocean water, and the chicks hatch during the austral winter, between late July and mid-August. Chicks are raised until they develop waterproof feathers, usually in December, before the summer melt. But if the ice melts too soon under their paws, they risk drowning and freezing.

Some colonies have moved

Fourteen of 66 penguin colonies, each capable of producing hundreds or even thousands of chicks per year, were affected by an early melt-off in 2023, according to the study. It results “high, even total, mortality levels”, said Peter Fretwell. However, the year 2023 “wasn’t as bad as we feared”, did he declare. Nineteen colonies were affected in 2022, a record.

Several colonies, including those that saw their broods decimated the previous year, moved in search of better ice. This encouraging sign of adaptation, however, is only one “temporary solution”warned Peter Fretwell, because “There are only so many places they can go.”

Emperor penguins have around 250,000 breeding pairs, all in Antarctica, according to a study published in 2020. In 2022 and 2023, the minimum area of ​​the sea ice, at the peak of the austral summer, has fallen below two million kilometers squares, for the first time since satellite surveys began. If carbon emissions and melting ice continue at current levels, the emperor penguin population is expected to decline by 99% by the end of the century, the study warns.