Why in news:
Up to 10,000 emperor penguin chicks across four colonies in Antarctica’s Bellingshausen Sea may have died as the sea ice underneath their breeding grounds melted and broke apart in late 2022, according to a new study.
About Emperor Penguins:
- The emperor penguin is the tallest and heaviest of all living penguin species.
- It is endemic to Antarctica.
- The male and female are similar in plumage and size.
- Like all penguins, it is flightless, with a streamlined body.
- While hunting, the species can remain submerged around 20 minutes.
- It has several adaptations to facilitate this:
- an unusually structured haemoglobin to allow it to function at low oxygen levels,
- solid bones to reduce barotrauma, and
- the ability to reduce its metabolism and shut down non-essential organ functions.
- It is the only penguin species that breeds during the Antarctic winter.
Significance of sea ice for emperor penguins:
- The role of stable sea ice in the emperor penguin breeding cycle is crucial.
- Emperor penguins spend their whole breeding cycle on the sea ice.
- The sea ice on which emperor penguins breed needs to remain stable between April to January to ensure successful breeding.
Key findings of the study:
- It’s the first recorded incident of widespread breeding failure of emperor penguins at multiple sites in a region due to sea ice loss.
- Since 2016, the Antarctic sea ice extent has been shrinking with the total area of frozen water around the continent reducing to new record low levels almost every year.
- Antarctic sea ice extent is the total region with at least 15% sea-ice cover.
- This puts more than 90% of emperor penguin colonies at risk as they may go extinct by the end of this century, if Earth continues to get warmer at the present rate.
- The findings show a clear link between negative sea ice anomalies and emperor penguin breeding failures.
- The Bellingshausen Sea region was the worst affected, during November, some parts saw a 100% loss in sea-ice extent.
- As a result, four out of five colonies witnessed complete breeding failure.
- Emperor penguins are known to tackle breeding failures caused by the localised disappearance of sea ice by moving to alternative, more stable sites the next year.
- However, given the large-scale shrinking of the sea ice extent, such a strategy will not be possible.
- “That’s why this (Bellingshausen Sea) regional failure is so difficult (for the penguins) because they can’t just go to the nearest colony… A 1,500km region in length has lost almost all its sea ice. We have no real idea what happens if there’s no ice,” Fretwell told The Guardian.
Antarctic sea ice extent shrinking
Like last year, the Antarctic sea ice extent has diminished to a new record low in 2023. But this time, the ice cover is exceptionally low. Throughout July 2023, sea ice averaged 13.5 million sq km, the lowest extent observed for this time of year since the continuous satellite record began in late 1978, according to a NASA Earth Observatory report.
Other implications of ice melting:
- Less sea ice exposes more of the continent’s ice to the open ocean, leading it to melt and break off more easily.
- This will contribute to rising sea levels, which can affect millions of people living in coastal regions.
- Decline in the ice sheet also causes a spike in sea surface temperatures as sea ice reflects solar rays back into space and thwarts heat from getting absorbed in the oceans.
- Warmer oceans mean more difficulty in the formation of ice and a wide range of other consequences.