(CN) – Emperor penguins have ditched a longtime love nest for three consecutive years as they search for stable ground while sea levels rise and fierce winds reshape the landscape of Antarctica, according to a study published Thursday.
For years, researchers have observed the breeding rituals of emperor penguins colonized at Halley Bay, located on the northern side of Antarctica’s Brunt Ice Shelf.
It is there that the tallest and heaviest of all living penguin species in the world would meet to breed, forage and incubate their chicks, thanks to ideal conditions, before moving out to sea.
Holes of unfrozen sea ice, known as polynyas, once embedded in larger, more stable ice floes at Halley Bay, created a buffet of nutrient-packed plankton that would serve the breeding birds.
But since 2016, there has been an exodus. According to findings based on a decade of research and published Thursday in the journal Antarctic Science, the stately birds have mostly given up on breeding at Halley Bay and instead have turned up en masse to another site nearby known as Dawson-Lambton.
“The breeding failure and reasons for relocation are almost certainly linked to the early breakup of sea ice at the Halley Bay site, but exactly why that breakup occurred is unknown,” the study states.
The study’s authors Peter Fretwell and Philip Trathan of the British Antarctic Survey also note, however, that the first year of poor sea ice conditions at Halley Bay – long considered to be one of the last strongholds of extreme cold in a rapidly warming world – only occurred after the strongest El Nino season on record in 60 years.
The El Nino phenomenon, the natural cyclical warming of the Central Pacific, creates strong winds and storms which can impact weather the world over. But when the warming phenomenon is prolonged or more generally intensified, it can lead to the break up and dissipation of sea ice in far flung and far colder locales such as Antarctica.
Heavy rains and some of the highest wind speeds ever recorded at Halley Bay occurred in September 2016, an event which also happened to coincide with the beginning of the emperor penguins withdrawal from the favored breeding grounds.
But without a longer recorded history of emperor penguin population data and sea ice records, the researchers admit it is “impossible to ascertain” whether similar population declines have also followed in previous years where a changing climate has altered the landscape.
Factors other than climate change may be causing the breeding ground’s failure, as well.
According to a different 2018 study cited by Fretwell and Trathan, the Brunt Ice Shelf and the adjoining Windy Creek, where the emperors would mate, is also on the move.
“The Brunt Ice Shelf is a fast-moving and dynamic environment. Over the last two decades the creek has gradually moved westwards by over 600 meters per year and it is possible that the migration and changing topography of Windy Creek has made it a less favorable site for emperor penguins,” Thursday’s study said.
It is also possible that some emperors could have formed a new colony elsewhere but after an exhaustive search of the region, no new colony locations have been spotted.
In an statement to Courthouse News on Thursday, Rod Downie, chief polar advisor for the World Wide Fund for Nature, said that while it wasn’t certain that the emperor’s catastrophic breeding failure was directly linked to climate change, the news still did not bear well for future penguin numbers.
“Scientists predict [it] may decrease by up to 70% by the end of this century. The main cause of this is our global climate crisis. Emperor penguins are perfectly adapted to survive in the most extreme conditions on earth, yet predictions show their numbers may decrease dramatically on our watch as the world warms. Even in the remote corners of our planet, there is no hiding from climate change,” Downie said. “We have the solutions to tackle this global climate emergency but we have to act now.”
Fretwell and Trathan’s study makes clear that any future breeding at Halley Bay hinges on the successful interplay of three factors: shelter, land stability and foraging opportunity.
While it may be possible that the birds that left Halley Bay will return, it could take years for resettlement to occur. “And it would likely only happen if conditions there improved,” the study states.
“In a warming world, it will be crucial to better understand the interplay between wind and ice shelf orography and to appreciate how these factors impact the location of emperor penguin colonies. Understanding how emperor penguins react to sea-ice loss will be of crucial importance if one is to predict the fate of the species over coming decades,” Fretwell and Trathan wrote.