Global warming impacts in the Arctic and Antarctic
The barometers of global climate change
Signs of unprecedented change abound at the Earth's poles. Sea ice in the Arctic has declined drastically in the last 30 years and the Northwest Passage was ice free for the first time in history in 2007. At the Arctic and Antarctic massive ice shelves are disintegrating and breaking away, such as the now famous break away of the Larsen B ice shelf in Antarctica in 2002.
But the signs of change at the poles are more pervasive than the attention grabbing declines of sea ice and collapsing ice shelves — and they affect us all.
A vast expanse of the Arctic is made up of permanently frozen ground, called permafrost. This frozen ground supports roads, pipelines, and buildings. As the temperatures increase the permafrost thaws and the infrastructure becomes twisted and unstable. 'Drunken forests', where the trees fall over as the ground beneath them thaws, has become a more common site.
View graphic of permafrost extent in the Arctic.
Beyond the visible impact of thawing ground is the threat posed by the carbon and methane that has been locked in the permafrost and beneath the cold arctic waters (in subsea permafrost) for millions of years. As the temperatures warm, these greenhouse gases are increasingly released into the atmosphere and cause further warming. This warming in turn releases more greenhouse gas, and unless it is stopped it will reach a "tipping point".
Once a tipping point has been reached a feedback process takes over and it would be near impossible to slow it down. Scientists are concerned that the release of carbon and methane from thawing permafrost in the Arctic could be one of several tipping points.
Another tipping point is the change in albedo (the extent to which a surface can reflect sunlight) from reflective ice and snow to absorbent open water. Snow sitting on top of the sea ice reflects about 90% of the sun's energy whereas open water absorbs about 94%. So as the open water of the ocean absorbs more heat and causes more sea ice to disappear it exposes even more water and another feedback process has begun.
View graphic of tipping points around the world
Impact on wildlife
Even small changes in the conditions are enough to have serious impacts.
In the Arctic a whole ecosystem relies on the presence of sea-ice. From the plankton that live on the bottom on the sea ice and all the way up to harp seals and polar bears.
Walrus are having a harder time as they rely on sea-ice floating close to land on which to haul out. As this sea-ice disappears some walrus pups drown at sea and others are crushed to death during stampedes on crowded beaches.
Read Russian story about impact of sea ice decline on walrus
The Emperor penguin colony at Terra Adelie in Antarctica could decline by 95% before the end of the century, if sea-ice continues to decline at the current rate. This would place the population at serious risk of extinction. Other Emperor penguin colonies could face a similar situation.