A report from WHO presenting an overview of the science of the links between climate change and human health. It provides an update of the evidence on health risks caused by climate change, describes which populations are most vulnerable, and outlines the actions that will be necessary to protect health from climate change. Although climate change presents a very serious threat to global public health, the key messages of the report are positive. The health sector already has at its disposal a number of effective interventions that would save lives now and reduce vulnerability to climate change in the future. In addition, there are many policy options in sectors such as transport and energy production, that could simultaneously improve health and reduce emissions of greenhouse gases that cause climate change. The report notes the rapid increase in engagement by the health community on climate change and health, and outlines priority actions to further support healthy and sustainable development.