Almost all the world's glaciers are now retreating. Permafrost in Alaska and Siberia, which has remained frozen since the last Ice Age, has started to melt. Parts of the Amazon rainforest are turning to savannah as the temperatures there exceed the point at which trees can survive. Coral reefs in the Indian Ocean and the South Pacific have begun to wilt. The World Health Organisation estimates that 150,000 people a year are now dying as a result of climate change, as diseases spread faster at higher temperatures. All this is happening with just 0.6 degrees of warming.