The 21st Conference of the Parties of the UN Framework Convention on Climate Change (COP21) will take place in December in Paris. It is an important opportunity to tackle the impact of climate change on health by drafting a genuine universal agreement which would put health to the foreground in the debate on climate change and would reduce the serious health-related risks the world faces today. The major, future climatic phenomena represent a significant risk both for health as well as for the lives of the most vulnerable people. The consequences on individuals’ health will vary substantially depending on their economic, social and cultural background. Public health actors and the entire global medical community welcome all measures which prevent the degradation caused by climatic events, the impact of which can be observed on a daily basis (floods, storms, desertification, changes to the ecosystem for both flora and fauna – including disease vectors – , extreme weather conditions…), and which prevent the direct and indirect consequences of these impacts on the health of individuals and populations: deaths and medical emergencies, infectious diseases, physical and mental disabilities, breakdowns within the healthcare supply chain and the existing health infrastructure, and mass displacement of populations. Any climate-related action that recognizes these challenges should maintain and improve health, benefit sustainable development and enhance worldwide equity.