A worrying new study published this week in the journal Scientific Reports provides evidence that up to 30 percent of the global Adélie penguin population could be in decline by 2060, with this figure rising to 60 percent by 2099.
Adélie penguins are found throughout the Antarctic continent, and as such are subject to some of the most unstable climatic conditions on Earth. Asymmetrical climate change at the world’s southernmost point means that while some parts of Antarctica remain relatively stable, other regions are rapidly warming. The West Antarctic Peninsula (WAP), for instance, is currently one of the fastest-warming places on the planet, prompting concern among scientists for the future of the region’s wildlife.
Interestingly, on geologic timescales, Adélie penguins have been positively affected by global warming, as retreating glaciers have exposed more bare rock nesting sites for the flightless birds to colonize. However, after going through several decades’ worth of satellite data, the study authors believe that “in many regions of Antarctica climate warming has tipped past peak suitability so that further warming is no longer beneficial to Adélie penguins.”
To conduct their study, the researchers analyzed satellite observations collected between 1981 and 2010, revealing the changing size and location of penguin colonies from year to year. When examining annual fluctuations in sea surface temperature and the availability of bare rock locations across this period, they were able to note some alarming trends regarding how these variables affect penguin populations.
For instance, during this period, the WAP experienced the highest number of “novel climate years”, meaning years in which sea surface temperatures were warmer than normal. These years were invariably accompanied by reduced penguin colony sizes, suggesting that high sea surface temperatures are detrimental to the birds’ health.
Expanding on this finding, the researchers then used future climate model projections to calculate how penguin colonies may fare over the remainder of this century. As the WAP is projected to continue experiencing high rates of novel climate and general warming of sea surface temperature, the study authors calculate that Adélie penguins in the region could take a monumental hit by 2099.
Though the mechanism behind this decline remains to be determined, the researchers propose that fluctuation of sea surface temperatures may reduce the availability of some of the penguins’ prey species.
Fortunately, however, the news isn’t all grim, as certain parts of Antarctica are expected to maintain a relatively stable climate over the coming decades, and may, therefore, provide vital refuges for the penguins. The Cape Adare region of the Ross Sea, for instance, is likely to remain hospitable for many years to come, and could play a key role in averting a species-wide decline in Adélie penguins.
Image in text: Soaring sea surface temperatures are negatively affecting penguin populations. Amelie Koch/Shutterstock
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