by Dorothy Hoffman

Created on: November 06, 2009

Millions of moviegoers fell in love with penguins in the recent box office hits, March of the Penguins and Happy Feet. The plucky, flightless birds are well adapted to aquatic life in some of the world harshest climate, but some species can also be found in equatorial ecosystems. Penguins can swim up to 35 km/hour and dive to depth of 520 meters or more to search for food. They mate and raise their chick on dry land or sea ice. Probably the best known species, the Emperor penguins of Antarctica, can endure temperatures down to 60C below zero and winds of 195 km/hour.

Eighteen penguin species inhabit a wide range of habitats in the Southern Hemisphere. The International Union for Conservation of Nature reports that 11 or these species are currently in decline and at risk for extinction. Climate change is a major factor in these population declines, affecting different species in different ways, depending on the type of ecosystem in which they live. For nearly all penguin species, global warming has reduced the available food supply, threatened penguin nesting grounds, and decreased the survival rates of chicks.

A recent study of the small population of Victoria's little penguins inhabiting Phillip Island found severe declines in average birth weight, with fewer chicks surviving to adulthood. The change appears to be related to stronger storms, which make it more difficult for the adults to find food. Warmer weather is also breaking up the penguin's feeding spots and disrupting their breeding habits.

A World Wildlife Fund-commissioned study on Antarctic Penguins and Climate Change showed that higher ocean temperatures have reduced Antarctica's sea ice by 40% from 26 years ago. The warmer waters have also greatly reduced the krill population, which is the main food for penguins. The krill population has declined by up to 80% since 1970, and further warming could kill off another 95% of the krill. With the warmer winters and more severe storms, some Emperor penguin colonies have been cut in half over the last 50 years.

While climate change is already affecting many ecosystems, the Antarctic is warming at a rate five times faster than the average global warming. This has shortened the sea ice season, threatening the entire food web of the area as well as the survival of the penguins. If the sea ice breaks up before the chicks have grown their waterproof feathers, they are likely to die in the ocean. The declining food supply also threatens the survival of adults.

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