The greatest danger to the survival of Antarctic penguins is human interference in the Antarctic ecosystem. From pollution to overfishing to climate change, humans are impacting every ecosystem on earth, including the Antarctic. Climate change is probably the biggest of those three threats to penguins. Penguins need ice, especially the Emperor penguins. They have to have ice solid enough to support them and their chicks for the long winter months. If the ice melts, there is less area for them to nest.
The Antarctic continent is actually two islands covered in and joined together by giant ice sheets. In addition there are vast areas of ocean covered by ice sheets. The size of the Antarctic doubles each winter as the ice spreads outwards in the freezing darkness. Abnormal melting began to occur back in the late 20th century due to the development of holes in the ozone layer because of the pollution of the atmosphere with CFC’s. Although the production of CFCs has been cut, the damage from existing CFCs in the atmosphere continues and the hole over the Antarctic still develops each summer. Because of this, there has been a loss of a lot of ice. If we continue to burn fossil fuels and cause global warming by contributing to the Greenhouse Effect, we could see catastrophic melting of Antarctic ice. As well as raising sea levels, Antarctic penguin numbers couid be adversely affected and extinctions are possible.
Penguins are both tough and vulnerable. They have chosen to live in some of the most extreme climates in the world. They can survive in the cold southern ocean and on the even colder climates of subantarctic islands and the coastal zones of the Antarctic continent. Emperor penguins take journeys that would kill all but the toughest humans and then survive without shelter in the sub-sub-sub-zero temperatures and howling winds of an Antarctic winter. They survive what would kill us in minutes through a combination of thick fat layers, thick feather layers and huddling together in large groups. Each generation of emperor penguins thus survives on a knife edge. Extinction could occur in a single worst-case winter. Nature or humans could tip the balance and we could lose these amazing animals forever.
Besides the climate, Antarctic penguins have a formidable number of predators to contend with too but predator-prey relationships being what they are, extinction is not likely to be caused by predators. Leopard seals, killer whales and sharks are all threats to individual penguins. Rather than endangering the species however, predation of this sort strengthens the overall gene pool by weeding out the unfit, the sick, the old and the unwary young. Over time, this selects for smarter, faster, stronger penguins and this has to be good for the populations as a whole, even as it is cruel to individual penguins and their young. During the nesting season, the loss of an adult bird to a leopard seal also means the death of the chick left behind because one parent cannot both feed and look after its offspring. But the overall result of predation is less a threat than a benefit to penguin populations.
The first human threat to penguins, isolated as they were in the Great Southern Seas, were whalers and sealers, who, when they couldn’t find enough bigger prey, were content to kill millions of penguins and boil them down for their fats and oils. Luckily the demise of the great whale stocks led to a collapse of this industry and accompanied by new sources of energy such as fossil fuels, most whale, seal and penguin species got a reprieve from human-induced extinction.
The next big human threat was two-fold: pollution and overfishing. Oil pollution has decimated a number of penguin populations, especially the African Penguin. However Antarctic penguins were relatively protected until the invention of CFCs and the resultant holes in the ozone layer. This and other pollution threats still exist but so far penguins have adapted and survived. Overfishing is going to impact on penguin populations too through the food chain and this is still a huge threat to penguins. If their food supply is decreased beyond a certain level, individual penguins will starve and potentially whole colonies and populations will die.
The other threat to Antarctic penguins and many other species as well is climate change and we cannot predict what long term effects climate change will have on either the Antarctic or its penguins. For our own sakes and the penguins, we need to examine our actions and plan for the future. Instead of just endlessly debating whether our polluting ways are actually causing climate change or whether we are just experiencing normal variations, we need to stop polluting the atmosphere and oceans with our industrial waste products. Even if it turns out that we weren’t really a threat to the earth’s climate, we will still win in the long run with a cleaner environment for all, penguins included.