Jean Pennycook (Penguin Science)
Life in Warming Polar Regions
Climate change is causing ecosystems to change. Spring events like flowers blooming and leaves growing happen earlier in the year. Plants and animals are found in places where they had not lived before, moving towards the Poles as climate warms. As the Earth continues to warm, more than 20 percent (one out of five) of plant and animal species will likely become extinct.
Ecosystems of the polar regions are no exception; both Arctic and Antarctic ecosystems have changed as climate has warmed. The Arctic ecosystems are changing very rapidly. Predictions for the future anticipate even more changes, according to the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC). A few of the changes to Arctic and Antarctic life that have been observed are described below.
Arctic
The Arctic tundra ecosystem is changing as the Arctic warms. Over the past 20 years the amount of Arctic tundra has decreased by approximately 18 percent. As the tundra has warmed, some areas have become home to shrubs. Other areas of tundra have been converted to wetlands as the frozen soils (permafrost) have thawed.
Birds that are not commonly found in the tundra are now starting to stay there for part of the year. The climate that they can survive in is shifting northward and so the birds are moving too. Other birds that are usually found in the Arctic are no longer able to find the food they need because the climate has become warmer. Marine mammals that live in the Arctic are also affected by climate shifts. Polar bears, which rely on sea ice as a platform to hunt for seals and other marine life, are declining as the sea ice melts.
Antarctic
Warmer temperatures mean that there is less sea ice in the Southern Ocean. Krill, a shrimp-like animal, live under sea ice. Without the ice, there is less krill. And without the krill, there is less food for penguins like the Adelie and Emperor.
Adelie penguins were once common on the Antarctic Peninsula. Now most Adelie penguin colonies in the area have been abandoned. Warming of the Antarctic is anticipated to happen much more slowly than the Arctic. However, the Antarctic Peninsula, the northernmost part of Antarctica, has been warming very fast – so there is less sea ice. The warmer temperatures appear to be good for other penguin species. The Gentoo and Chinstrap penguins have expanded their range into the area of the Antarctic Peninsula where the Adelie used to live. Elsewhere on Antarctica, where the effect of warming is still small, the Adelie penguins continue to live. Scientists are studying the Adelie penguins to better understand how they will be affected by global warming.
Like Adelie penguins, Emperor penguins also rely on sea ice. They need the ice, not only as a place to find food, but also for nesting sites. Emperor penguins raise their chicks on sea ice. If warmer temperatures cause the ice to melt earlier in the spring, before the chicks are large enough to swim, the chicks will drown. Over the past 50 years, the number of Emperor penguins has dropped by half.
