Climate change is likely to create more extreme weather variability (IPCC, 2007). This will have serious impacts on population health in many parts of the world (Kirch et al., 2005). There is also the risk of substantial sea level rise, which may force the displacement of millions of people (McGranahan et al., 2007). At the same time, extreme weather situations will cause emergencies through floods, landslides blocking roads and damaging houses, windy typhoons or hurricanes damaging electricity supply, water supply, buildings and other infrastructure.

The most vulnerable will be poor people and people with pre-existing chronic diseases or disabilities, and the greatest population impacts are likely to be in densely populated cities (Haq et al., 2007; de Sherbinin et al., 2007).