The Rise and Fall of Penguins: 30,000 Years Reveal History of Climate Change Impacts

The rise and fall of penguin populations may be key to understanding the influence of climate change. Scientists have taken a closer look at penguin populations over the last 30,000 years and have found that the climate warming and retreating ice of today may affect penguins in a more complicated way than first thought.

The scientists used a genetic technique to estimate when current genetic diversity arose in penguins and to recreate past population scientists. More specifically, the researchers looked at the 30,000 years before human activity impacted climate.

So what did they find? It turns out that as the Antarctic gradually warmed, three species of penguin, including the Chinstrap, the Adelie and the southern populations of Gentoo penguins, increased in numbers. In contrast, the Gentoo penguins on the Falkland Islands were relatively stable since they weren't affected by large changes in ice extent.

"Whereas we typically think of penguins as relying on ice, this research shows that during the last ice age there was probably too much ice around Antarctica to support the large populations we see today," said Gemma Clucas, one of the researchers, in a news release. "The penguins we studied need ice-free ground to breed on and they need to be able to access the ocean to feed. The extensive ice-sheets and sea ice around Antarctica would have made it inhospitable for them."

In fact, it seems as of the penguins are climate change "winners" in the long haul. Yet surprisingly, this isn't the same pattern seen today. The Adelie and chinstrap seem to be declining.

"Despite historic warming clearly opening up new opportunities for penguins, we should not assume that current rapid warming caused by human activity is good for penguins as a whole," said Clucas in a news release. "Evidence from other studies shows that climate change today is creating lots of losers and few winners-with chinstrap and Adelie populations around the Antarctic Peninsula declining fast. This is probably as a result of reductions in sea ice causing stocks of the krill they feed on to shrink, whilst populations of Gentoo penguins, which don't rely on kirll as much, grow and expand.

The findings are published in the journal Scientific Reports.