Over the last 50 years, human activities - particularly the burning of fossil fuels - have released sufficient quantities of carbon dioxide and other greenhouse gases to trap additional heat in the lower atmosphere and addict the global climate in the last 130 years, the world has warmed by approximately 0.85oC. Each of the last 3 decades has been successively warmer than any preceding decade since 1850. The seas levels are rising glaciers are melting and precipitation patterns are changing. Extreme weather events are becoming more intense and frequent. Although global warming may bring some localized benefits, such as fewer winter deaths in temperate climates and increased food production in certain areas, the overall health effects of changing climate are likely to be overwhelmingly negative. Climate change affects social and environmental determinants of health - clean air, safe drinking water, sufficient food and secure shelter.