Extract from ABC News
Thousands of baby emperor penguins drowned last year in Antarctica as sea ice broke up early and reached record lows, British researchers say, reinforcing dire predictions about the future survival of the species.
Key points:
- 10,000 emperor penguin chicks may have died in one part of Antarctica, scientists say
- The sea ice the species breeds on reached record-low levels last year
- Scientists say changing the trajectory of climate change will reduce the damage in future
Research published today shows four of five colonies in an area off the Antarctic Peninsula, called the Bellingshausen Sea, suffered what researchers call a "catastrophic breeding failure".
Warming seas caused the sea ice that baby penguins live on to break up early, researchers say, killing them before they had matured enough to survive in the water.
Observing five colonies in the Bellingshausen Sea region, west of the Antarctic Peninsula, the researchers believe all chicks were killed within four colonies.
As many as 10,000 baby penguins may have died in those colonies, the lead author on the study told the ABC, pointing the blame at human-induced climate change.
"Climate change is really the elephant in the room," the British Antarctic Survey's Peter Fretwell said.
"You really have to include climate change in the equation to make the models of what's happening with sea ice work at the moment. But it's the obvious conclusion you have to make here."
It is the first time such widespread regional breeding failure has been seen in emperor penguins and follows projections the species will be all but extinct by the end of this century.
"That's the first time really, where we've seen this type of breeding failure due to sea ice loss since we've been studying penguins for the last 15 years," Dr Fretwell said.
"It's sort of a sign of things to come, that we expect to happen, with the declining sea ice around the continent."
But more recent work by the same team, not yet published, suggested the fate of emperor penguins in 2022 was even worse than the paper published today demonstrates.
Dr Fretwell said they had since looked at every known emperor penguin colony in Antarctica and found more than a fifth had total breeding failure — meaning no chicks were thought to have survived — with even more seeing some losses.
Worse still, the researchers are waiting anxiously to see what happens to the penguins this year, since the sea ice was tracking at even lower levels, likely to drown and freeze even more baby penguins.
"It's going to probably be an even worse year in 2023. So it looks like we're having three years of breeding failure, which is unsustainable if it carries on like this," Dr Fretwell said.
Why shrinking sea ice threatens emperor penguins
For years scientists have warned that global warming could lead to the demise of emperor penguins, because the sea ice they depend on for breeding and raising their young is shrinking.
In their breeding cycle, babies usually hatch about August. They then are supported by their parents until November or December when their waterproof feathers have grown, and they can fend for themselves.
If the sea ice the chicks are on breaks up before they have their waterproof features, the chicks fall in the water. If they cannot get back onto some ice, they drown. But if they do get back onto ice, their fluffy feathers are sodden and freeze, killing the baby penguins.
Either way, if the sea ice breaks up, the baby penguins die, Dr Fretwell said.
During the 2022 period the researchers studied, some parts of Antarctica saw a total loss of sea ice.
In 2021, researchers published work suggesting nearly all emperor penguins would be dead by 2100, unless greenhouse gas emissions were curbed.
Dr Fretwell said despite all the bad news, there was still hope for the penguins.
"That does depend upon the trajectory of climate change that we put the planet on. If you can change that trajectory, then … like many of the species around the world, we will be able to save penguins," he said.
Justine Shaw, an ecologist from Queensland University of Technology who works on Antarctic conservation, said the results were "depressing".
"We know when we lose multiple colonies, all in one go, that has huge implications for the whole global population," Dr Shaw said.
But she warned the penguins were just the tip of the iceberg.
"If we're losing sea ice, it's not just affecting the penguins — it's affecting all of the animals that live and survive in the Southern Ocean," Dr Shaw said.
"Every species in the Southern Ocean is reliant and influenced by sea ice. As that sea ice changes, that impacts the krill, the fish, the albatross, the petrels, the whales and the seals."
Many species feeling the impact of climate change
This sort of sudden collapse of populations driven by climate change has been documented and projected before.
"Those sorts of biological tipping points are actually quite common," said Professor Lesley Hughes, an ecologist and climate scientist from Macquarie University.
"And the problem with climate change is that we're seeing those biological thresholds starting to be exceeded for lots and lots of different species," said Professor Hughes, who is also a director at the Climate Council, which advocates for stronger action on climate change.
In 2021, researchers including Professor Hughes, identified 19 Australian ecosystems that were now collapsing, many driven by the warming climate.
"We documented instances where getting to these biological thresholds — be they temperature or lack of rainfall or whatever — was causing very sudden impacts," she said.
"So, things just sort of … fall off some sort of climate cliff."
Professor Hughes said it was clear what needed to be done to minimise the destruction.
"We just have to … very, very rapidly transition out of digging up fossil fuels, exporting them and burning them," she said.
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