Arctic Ocean

A report on the BBC's web site warns that the Arctic Ocean may be close to tipping point and that it may be free of summer ice by 2040. The site explains that data presented at the American Geophysical Union suggests the ice is no longer showing a robust recovery from the summer melt. This would be part of a global chain reaction in which reduced ice cover means more heat absorption by oceans, accelerating global warming and thereby melting even more ice. ."
Eventually, she said, the system would be "kicked over the edge", probably not even by a dramatic event but by one year slightly warmer than normal. Very rapid retreat would then follow. Locally, this would have major consequences for wildlife in the region, not least polar bears which traverse ice-floes in search of food, as those of you who have watched Planet Earth will have seen.
Loss of summer ice would seriously compromise the lifestyles of the region's indigenous peoples, though it could also bring new trading opportunities as sea routes opened up.
On a global scale, the Earth would lose a major reflective surface and so absorb more solar energy, potentially accelerating climatic change across the world.