Lancet and University College London Institute for Global Health Commission. Managing the health effects of climate change

Climate change is the biggest global health threat of the 21st century: Effects of climate change on health will affect most populations in the next decades and put the lives and wellbeing of billions of people at increased risk. During this century, earth's average surface temperature rises are likely to exceed the safe threshold of 2°C above preindustrial average temperature. Rises will be greater at higher latitudes, with medium-risk scenarios predicting 2-3°C rises by 2090 and 4-5°C rises in northern Canada, Greenland, and Siberia. In this report, we have outlined the major threats-both direct and indirect-to global health from climate change through changing patterns of disease, water and food insecurity, vulnerable shelter and human settlements, extreme climatic events, and population growth and migration. Although vector-borne diseases will expand their reach and death tolls, especially among elderly people, will increase because of heatwaves, the indirect effects of climate change on water, food security, and extreme climatic events are likely to have the biggest effect on global health. A new advocacy and public health movement is needed urgently to bring together governments, international agencies, non-governmental organisations (NGOs), communities, and academics from all disciplines to adapt to the effects of climate change on health. Any adaptation should sit alongside the need for primary mitigation: reduction in greenhouse gas emissions, and the need to increase carbon biosequestration through reforestation and improved agricultural practices. The recognition by governments and electorates that climate change has enormous health implications should assist the advocacy and political change needed to tackle both mitigation and adaptation. Management of the health effects of climate change will require inputs from all sectors of government and civil society, collaboration between many academic disciplines, and new ways of international cooperation that have hitherto eluded us. Involvement of local communities in monitoring, discussing, advocating, and assisting with the process of adaptation will be crucial. An integrated and multidisciplinary approach to reduce the adverse health effects of climate change requires at least three levels of action. First, policies must be adopted to reduce carbon emissions and to increase carbon biosequestration, and thereby slow down global warming and eventually stabilise temperatures. Second, action should be taken on the events linking climate change to disease. Third, appropriate public health systems should be put into place to deal with adverse outcomes. While we must resolve the key issue of reliance on fossil fuels, we should acknowledge their contribution to huge improvements in global health and development over the past 100 years. In the industrialised world and richer parts of the developing world, fossil fuel energy has contributed to a doubled longevity, dramatically reduced poverty, and increased education and security for most populations. Climate change effects on health will exacerbate inequities between rich and poor: Climate change will have its greatest effect on those who have the least access to the world's resources and who have contributed least to its cause. Without mitigation and adaptation, it will increase health inequity especially through negative effects on the social determinants of health in the poorest communities. {A figure is presented}. Despite improvements in health with development, we are still faced with a global health crisis. 10 million children die each year; over 200 million children under 5 years of age are not fulfilling their developmental potential; 800 million people go to bed each night hungry; and 1500 million people do not have access to clean drinking water. Most developing countries will not reach the Millennium Development Goal health targets by 2015. In September, 2008, the WHO Commission on Social Determinants of Health rep