In Antarctica, Climate Change Disrupts Penguin Lifecycles

RITURAJ PHUKAN

Increases in global temperatures place significant stress on various species, prompting them to migrate to cooler regions or leading to population declines. In the polar region of Antarctica researchers have found that penguins have substantially altered their breeding season, apparently as an adaptive response to climate change. Meanwhile, Antarctica saw its warmest annual temperature on record in 2025 and the sea ice cover in February was at its lowest value since the beginning of satellite observations.

A ten-year study conducted by Penguin Watch in collaboration with the University of Oxford and Oxford Brookes University has identified significant changes in penguin behaviour, including a shift in breeding periods that now occur more than three weeks earlier for certain populations. The alterations may jeopardise penguins’ access to food sources, heightening concerns regarding their long-term survival.

The researchers investigated shifts in the timing of penguin breeding from 2012 to 2022, focusing on the initial date when penguins continuously occupied a nesting area, which is referred to as settlement at a colony. The study encompassed Adélie, Chinstrap, and Gentoo penguins, with colony sizes ranging from approximately twelve nests to several hundred thousand nests.

Researchers collected data using 77 time-lapse cameras strategically placed at 37 colonies across Antarctica and several sub-Antarctic islands. Each image captured by the cameras was accompanied by a record of the corresponding air temperature. According to findings published in the Journal of Animal Ecology, the onset of the breeding season for all three species occurred earlier than previously recorded.

Gentoo penguins exhibited the most notable shift, with an average advancement in breeding timing of 13 days over the past decade, and up to 24 days observed in certain colonies. This constitutes the most rapid change in phenology documented for any bird species, and potentially for any vertebrate. Adélie and chinstrap penguins also advanced their breeding by an average of 10 days.

Gentoo penguins, which prefer milder climates, are seeing their populations grow in all of their colonies as they benefit from warmer temperatures. These penguins are also spreading to new areas along the Antarctic Peninsula. In contrast, Adélie and Chinstrap penguin numbers are declining.

The exact reason why these brush-tailed penguins are breeding earlier is still unknown. They might be responding to warmer temperatures, earlier breakup of ice, snowmelt, and phytoplankton blooms, or a combination of other factors, as seen with many other animals and plants. The rapid shifting breeding periods could result in competition for space and nesting sites among the three species.

The three species of Pygoscelispenguins have thrived together in the Antarctic peninsula with minimal competition, with a staggered reproduction cycle, with Adélieand Chinstraps breeding periods occurring before that of the Gentoos. The three penguinsalso have other differenceslike preferred hunting depths and sea-ice conditions which traditionally helped them to avoid competition.

While Gentoos are foraging generalists when it comes to choice of food, switching from krill to fish when required, Chinstraps and Adélieare krill specialists and suffer during low-krill years. Increased competition for food, other resources and snow-free nesting space would make raising chicks more difficult. Researchers have also observed Gentoos occupy nests that were previously occupied by Adélies or Chinstraps.

Previous studies have projected anuncertain futurefor another of the Antarctic breeding species, theEmperor penguin, which is also the largest living species of penguins. A study published last year predicted that Emperor populations will decline rapidly over the current century owing to habitat loss in Antarctica arising from warming oceans and loss of seasonal sea ice.

Contrary to popular belief, penguins live on other continents too, including Africa, Australia and South Americain the Southern Hemisphere.The Galapagos penguin livesnorth of the equator andis the only endangered among the 18 species of penguins, due to climate change and specifically due to El Nino conditions.

It must also be mentioned that penguins are perhaps the only species to have two designated days on the environmental calendar. Penguin Awareness Day is observed on January 20 each year, while World Penguin Day is celebrated on April 25. Both days serve to raise awareness about the conservation of penguins and the threats they face from environmental changes and human activities.

Going back to Antarctica, penguins are integral to food webs, contributing to nutrient transfer from deep water to the surface, which is essential for algal photosynthesis. Based on the recent study, researchers are concerned that the projected loss of penguin species could elevate the risk of widespread ecosystem destabilization across Antarctica.

All Photographs by Rituraj Phukan [ Headline Pic caption- “Decreasing krill populations is negatively impacting Chinstrap Penguins at Antarctica”]

RITURAJ PHUKAN : Founder, Indigenous People’s Climate Justice Forum; Co-Founder, Smily Academy ;National Coordinator for Biodiversity, The Climate Reality Project India; Member, IUCN Wilderness Specialist Group; Commission Member – IUCN WCPA Climate Change, IUCN WCPA Connectivity Conservation, IUCN WCPA Indigenous People and Protected Areas Specialist Groups, IUCN WCPA South Asia Region and IUCN WCPA-SSC Invasive Alien Species Task Force; Member, International Antarctic Expedition 2013; Climate Force Arctic 2019 ; Ambassador, Marine Arctic Peace Sanctuary. Rituraj Phukan is the Climate Editor, Mahabahu and the Convenor, Mahabahu Climate Forum.

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