Penguins have become more than just a symbol of the frozen south of the earth. Researchers now use them as indicators of climate change near the South Pole. Certain western regions, such as the Antarctic Peninsula, have experienced rapid warming while East Antarctica remains cold and ice-covered.
Nothing is easy in the remote and icy reaches of Antarctica, but penguins are easier to track than other species because they nest on land and their black feathers and waste can be observed against the white ice.
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“We are counting penguin nests to understand how many penguins are in a colony, producing chicks every year, and whether that number is going up or down with the environmental conditions,” said Borowicz, of Stony Brook University in New York.
“We can use penguins as a bioindicator to see how the rest of the ecosystem is operating,” said Wethington, also of Stony Brook.
Counting individual penguins along with other methods such as satellite images provide a nuanced picture, showing some penguins dubbed ‘winners’ prosper as climate change opens new habitats, while others are compelled to migrate to colder climates.
The Gentoo penguin, with its bright orange beak and distinctive white marking on its head, prefers open water with chunks of ice bobbing about.
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During the latter half of the 20th century, temperatures on the Antarctic Peninsula began rising faster than almost anywhere else in the world, leading to Gentoo populations expanding southwards – known as the “gentoofication” of Antarctica.
The reduction of sea ice at the western end of the peninsula has enabled the Gentoos to thrive. For tuxedo-wearing Adelies, which rely on sea ice for breeding and feeding, the same conditions have made it worse.
“When we find Adelie penguins, we typically know that sea ice is nearby,” Wethington said. “And whenever we’ve seen sea ice declining or disappearing altogether, then we’re seeing corresponding Adelie penguin populations decline substantially.”
Overall, Adelie penguin populations are increasing, but some populations have declined by more than 65 per cent.
Scientists from Stony Brook University made an expedition to the region in January and found that Adelie colonies around the still-icy Weddell Sea had remained stable over the past decade.
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“This peninsula is maybe a safe space as we see climate change progressing and overall warming throughout the globe,” Wethington said.
MV Arctic Sunrise expedition leader Heather Lynch believes the findings point to the conservation value of the region.
Using satellite images, a team from the British Antarctic Survey discovered 11 new emperor penguin colonies in 2020, increasing known colonies by 20 per cent.
The Halley Bay colony, on the most eastern side of the Weddell Sea, is home to the second-largest breeding colony of emperor penguins in the world, with about 25,000 breeding pairs gathering each year.
However, since 2016 every chick in this colony has perished.
Researchers believe the 2016 El Niño event altered the sea ice dynamics in the area, and penguins are at risk as climate change increases the frequency and severity of El Niños.
In spite of the chicks’ deaths not being directly linked to climate change, Peter Fretwell, a geographic information scientist with the British Antarctic Survey, noted there was a climate change component to the loss.
(With inputs from agencies)
