Emperor penguin numbers could plummet as Antarctica warms: study

The iconic imagery of legions of emperor penguins marching along the frozen landscape of Antarctica could become a thing of the past by the next century.

According to a new study by an international team of scientists released in this week's Nature Climate Change, the populations of this flightless top predator may be on a drastic and quick decline due to changes in shifting sea ice conditions.

While the data shows there are variations in populations among the 45 individual colonies that are scattered across the frozen continent, the overall trends are undeniable and sobering. At least two-thirds of the penguin colonies are now predicted to have their numbers dropping by more than 50 per cent from the current size by the year 2100. After that the decline will continue at the rate of 3.2 per cent annually, according to the new study's forecast.

Currently the global population of this majestic penguin that stands 1.2 meters tall, and is the largest of all penguin species, is around 600,000. Conservationists believe their numbers are nearly stable or near threatened for now; however, already most of the 18 other species of penguins are decreasing and are officially considered threatened.

Recent satellite imagery of scat-stained snow from emperor penguins have made more accurate population estimates possible.

This same data however is also showing that the winter sea ice coverage around the continent, which the penguins rely on as their unique breeding grounds, has expanded in recent years to encompass as much area as Mexico and United States combined. Computer forecasts however say this trend will reverse as the Antarctic region warms.

But the emperors require a delicate balance when it comes to sea ice. For now the more ice there is, the longer the females have to trek to reach the waters for their food sources, like fish and tiny shrimp-like krill. However their situation is just as dire if the sea ice melts too fast. Less ice means colonies can be disrupted and nesting grounds destroyed.

Therefore the penguins are highly sensitive to the overall changes in the sea ice conditions, which the study says can also affect the abundance of krill and make the penguins vulnerable to predators as they need to forage longer and longer distances.

But could the majestic emperor penguin be like the canary in the coal mine for climate change?

Are they the only species under this particular threat, or are they signaling what will happen to other wildlife species in Antarctica?

Changes in the krill population would be worrisome, since they are a critical species in the Antarctic food chain as a whole.

Also, human activity is adding to the a crisis facing Antarctica's wildlife. Annually more than 40,000 scientists and tourists visit Antarctica, which holds the danger of bringing pollution and invasive species to fragile ecosystems.

But as climate change progresses in the coming decades and sea levels change and ice shelves melt along the continents' edge, critical wildlife sites will be put at risk. Populations of not only penguins, but seals, whales and a whole host of smaller creatures, will be affected.

For now survival will most likely rest on how adaptable they are as a species to the rapidly changing environment caused by climate change, and if they are capable of moving their nesting sites to higher ground.

There may be promising signs of this happening already as a handful of emperor colonies appear to have been spied on much higher ice shelves of the continent, away from the shifting sea ice.

(Photo courtesy of Reuters)

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