There is strong evidence that extreme weather events – such as hurricanes, floods, droughts and heat waves – are increasing because of climate change. In fact, the Financial Initiative of the UN Environment Programme (UNEP) recently calculated that the economic costs of global warming are doubling every decade. The cumulative number of people affected by disasters rose to two billion in the 1990s, up from 740 million in the 1970s. Virtually all of these millions were concentrated in poorer countries.