The death of thousands of baby penguins by melting ice – 29/08/2023 – Environment

Up to 10,000 emperor penguin chicks are estimated to have died catastrophically in Antarctica by the end of 2022.

The sea ice pack under these hatchlings melted and broke off before they could develop the waterproof feathers needed for the species to swim in the sea.

The birds probably drowned or froze to death.

Recorded by satellites, the event took place in the west of the continent, in an area facing the Bellingshausen Sea.

Peter Fretwell of the British Antarctic Survey (BAS) think tank says the mass deaths were a harbinger of things to come.

More than 90% of emperor penguin colonies are predicted to be extinct by the end of the century, as seasonal sea ice on the Antarctic continent shrinks on an increasingly warmer planet.

“Emperor penguins depend on sea ice for their reproductive cycle, which forms the stable platform they use to raise their young. But if that ice pack isn’t as extensive as it should be or breaks down more quickly, these birds will be at risk”, says the scientist to the BBC.

“There is hope: we can reduce our warming carbon emissions. If we don’t, we will drive these beautiful and iconic birds to the brink of extinction.”

Fretwell and his colleagues reported the death in the scientific journal Communications Earth & Environment.

Scientists tracked five colonies in the Bellingshausen Sea region – Rothschild Island, Verdi Inlet, Smyley Island, Bryan Peninsula and Pfrogner Point.

Using satellites, they were able to observe penguin activity from the droppings they leave on sea ice.

The brown coloring mark is visible even from space.

Adult birds dive into sea ice around March, as winter in the Southern Hemisphere approaches. They mate, lay eggs, hatch those eggs, and then feed their young over the next few months, until it’s time for the young to move on on their own.

This usually happens around December/January when the new birds head out to the ocean.

But the team of scientists watched as the sea ice beneath the emperor penguin colonies broke up in November, before thousands of chicks had time to shed their feathers for the ones needed for swimming.

As a result, four of the colonies suffered complete reproductive failure. Only the northernmost one, on Rothschild Island, has had any success.

Antarctic summer sea ice has seen a sharp drop since 2016, with the total area of ​​frozen water across the continent decreasing to new record lows.

The two worst years in absolute terms came in the last two summer seasons, in 2021/22 and 2022/23, when the Bellingshausen Sea was almost completely devoid of ice cover.

Furthermore, the slowness in the formation of ice packs in recent months means that the colonies are unlikely to produce babies for at least another year.

The maximum extent of winter sea ice, normally reached in September, will be far below where it normally would be.

Fretwell and his colleagues said that emperor penguins are feeling the impacts of this change in their habitat.

Between 2018 and 2022, about a third of the more than 60 known colonies of emperor penguins were affected in some way by decreasing sea ice extent – ​​either from late-season ice formation or earlier breakage.

At the other end of the planet, in the Arctic, sea ice has been in steady decline for decades. Antarctica, in contrast, looked more robust. Until 2016, its area was becoming a little more extensive year after year.

Caroline Holmes, an expert on Antarctic sea ice, links the causes of the current decline to extraordinarily warm ocean water across the continent and a particular pattern of winds that, in the case of the Bellingshausen Sea, pushed the ice back towards the coast, making its spread difficult.

“What we are seeing now is very different from what we saw before. We expected changes, but not so much, not so quickly,” she tells the BBC.

“Studies in the Arctic have suggested that if we could somehow reverse climate warming, sea ice at the North Pole would recover. Whether this also applies to Antarctica remains to be seen. But it seems likely that this would apply to Antarctica as well. : if it cools enough, sea ice will reform.”

Emperor penguins are currently classified as “near threatened” by the International Union for Conservation of Nature (IUCN), an organization that creates lists of the most threatened animals on Earth.

A proposal has been made to elevate emperor penguins to the more urgent category of “vulnerable” due to the danger that global warming poses to their life cycle.

This text was originally published here.