If greenhouse gases are pumped into the atmosphere at current rates and global temperatures spike 5 to 6C, relative to pre-industrial levels, there will be an average 86 percent decline in populations by the year 2100.
Stephanie Jenouvrier, lead author of a study published in the journal Global Change Biology and Woods Hole Oceanographic Institution (WHOI) seabird ecologist, said in a statement: “At that point, it is very unlikely for them to bounce back.”
“Under that scenario, the penguins will effectively be marching towards extinction over the next century,” she warned.
Some 80 percent of emperor penguin colonies are expected to decline by more than 90 percent, to become what is known as quasi-extinct due to the loss of Antarctic sea ice. Also known as populations collapse, a quasi-extinction is where there aren’t enough animals for a species to survive.
The animals breed on the platform in the winter, and rear their offspring in the spring. In the season when they don’t breed, it is a platform where they feed, molt, and stay safe from predators. It’s also important for maintaining a supply of krill and silverfish for the birds to feed on.
Scientists predict antarctic sea ice will decline by 48 percent if current warming trends continue, and the most endangered colonies in Queen Maud, Enderby and Kemp Land will see the ice totally vanish during the “critical” laying season.
Researchers used computer models featuring data on the global climate and penguin populations to carry out their study
Under the worst conditions predicted by the researchers, “the species will go extinct rapidly,” they said.
However, if countries fulfil the Paris Agreement aim to keep average global temperatures from rising above 1.5 to 2C, relative to pre-industrial levels, many animals could be saved. 19 percent and 31 percent of the colonies, respectively, would be quasi-extinct by 2100.
Jenouvrier explained: “We’ve been developing that penguin model for 10 years. “It can give a very detailed account of how sea ice affects the life cycle of emperor penguins, their reproduction, and their mortality.”
Peter Fretwell, remote sensing specialist here at British Antarctic Survey, who did not work on the study, told Newsweek the research shows that emperors cannot react through natural adaptation in time to halt the decline of their population due to climate change but that meeting the terms of the Paris Agreement provides some hope.
“The difference between a scenario where we do halt global warming and one where we don’t is stark. It really is up to us. If we do not halt climate change then this species and many others will be in jeopardy,” said Fretwell.
“There is still time, but not too long. The recent groundswell of support, interests and concern is promising. As scientists all we can do is keep highlighting the evidence.”
Fretwell added: “Many species, not just penguins, will be affected by warming temperatures. There will be winners and losers. Adelie penguins also rely on sea-ice and these could come under threat if temperatures continue to warm.”
The study is the latest to find that climate change is bad news for penguins. Last month, researchers recommended the International Union for Conservation of Nature raise emperor penguins’ status from “near threatened” to “vulnerable” on its Red List of Threatened Species. It also asked the Antarctic Treaty to list the animals as a protected species.
Philip Trathan, head of conservation biology at the British Antarctic Survey, who lead the study, said at the time: “The current rate of warming in parts of the Antarctic is greater than anything in the recent glaciological record. Though emperor penguins have experienced periods of warming and cooling over their evolutionary history, the current rates of warming are unprecedented.”
Trathan added: “Currently, we have no idea how the emperors will adjust to the loss of their primary breeding habitat—sea ice. They are not agile and climbing ashore across steep coastal land forms will be difficult. For breeding, they depend upon sea ice, and in a warming world there is a high probability that this will decrease. Without it, they will have little or no breeding habitat.”
