At the bottom of the world, emperor penguins have experienced tragedy.
Scientists at the British Antarctic Survey report an "unprecedented breeding failure" in some big, well-observed colonies where sea ice had largely or completely vanished in 2022. The study, published in the science journal Communications Earth & Environment, concluded it's likely that zero chicks survived from four of the five known colonies in the central and eastern Bellingshausen Sea, located off the Antarctic Peninsula. Over 9,000 chicks died.
Satellite images, from the European Space Agency's Sentinel-2 spacecraft, show the stark disappearances of breeding colonies, particularly the vivid comparison below.
"We have never seen emperor penguins fail to breed, at this scale, in a single season," Peter Fretwell, a scientist at the British Antarctic Survey who led the research, said in a statement. "The loss of sea ice in this region during the Antarctic summer made it very unlikely that displaced chicks would survive."
The chicks, just recently-born, would not have been old enough to grow their water-resistant feathers, the science institute explained.
The two photos below show a region off of Antarctica's Smyley Island. On left, the colony, stained by the penguin's guano, is conspicuous on the ice in October 2022. By December, the colony had completely vanished. (The researchers also captured before-and-after images of colonies at Rothschild Island, Verdi Inlet, Bryan Peninsula, and Pfrogner Point.)
"Emperor penguins have previously responded to incidents of sea ice loss by moving to more stable sites the following year," the British Antarctic Survey explained. "However, scientists say that this strategy won’t work if sea ice habitat across an entire region is affected."
Antarctic sea ice has dropped considerably in recent years, and in August 2023 is at a record low for the continent's winter. "This missing area is larger than the size of Greenland, or around ten times the size of the United Kingdom," the institute said.
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While historically unprecedented declines in Arctic sea ice are unquestionably driven by climate change, scientists are still observing Antarctic activity to see if recent losses are an unambiguous trend.
"There is some discussion about the Antarctic sea ice undergoing a regime-shift since 2016 toward a generally lower extent, and that maybe this could be a response to global warming; that is, the warming signal is starting to be seen in the Antarctic sea ice above the year-to-year variability," Walt Meier, a sea ice scientist at the National Snow and Ice Data Center (NSIDC), told NASA this year. "But it is hard to say at this point if it is a real shift and response to warming, or just a temporal multi-year variation."
What is clear, however, is emperor penguins need sea ice, and the recent declines have been devastating.
