Emperor penguin colonies experienced unprecedented breeding failure in a region of Antarctica where there was total sea ice loss in 2022. The discovery supports predictions that over 90% of emperor penguin colonies will be quasi-extinct by the end of the century, based on current global warming trends.
In a new study published today in Communications Earth & Environment, researchers from British Antarctic Survey discussed the high probability that no chicks had survived from four of the five known emperor penguin colonies in the central and eastern Bellingshausen Sea. The scientists examined satellite images that showed the loss of sea ice at breeding sites, well before chicks would have developed waterproof feathers.
Emperor penguins are dependent on stable sea ice that is firmly attached to the shore (‘land-fast’ ice) for the majority of the year, from April through to January. Once they arrive at their chosen breeding site, penguins lay eggs in Antarctic winter from May to June. Eggs hatch after 65 days, but chicks do not fledge until summer, between December and January.
At the beginning of December 2022, the Antarctic sea ice extent had matched the previous all-time low set in 2021. The most extreme loss was seen in the central and eastern Bellingshausen Sea region, west of the Antarctic Peninsula where there was a 100% loss of sea ice in November 2022.
Lead author of the study, Dr Peter Fretwell, said:
“We have never seen emperor penguins fail to breed, at this scale, in a single season. The loss of sea ice in this region during the Antarctic summer made it very unlikely that displaced chicks would survive.
We know that emperor penguins are highly vulnerable in a warming climate – and current scientific evidence suggests that extreme sea ice loss events like this will become more frequent and widespread.
Since 2016, Antarctica has seen the four years with the lowest sea ice extents in the 45-year satellite record, with the two lowest years in 2021/22 and 2022/23. Between 2018 and 2022, 30% of the 62 known emperor penguin colonies in Antarctica were affected by partial or total sea ice loss. Although it is difficult to immediately link specific extreme seasons to climate change, a longer-term decline in sea ice extent is expected from the current generation of climate models.
