The purpose of this document is to provide a response by the WMA on behalf of its members to the challenges imposed on health and healthcare systems by climate change. Although governments and international organizations have the main responsibility for creating regulations and legislation to mitigate the effects of climate change and to help their populations adapt to it, the World Medical Association, on behalf of its national medical association members and their physician members, feels an obligation to highlight the health consequences of climate change and to suggest solutions. The 4th Assessment Report of the International Panel on Climate Change (IPCC) contains a full chapter on human health impacts (AR4 Chapter 8 Human Health1), including a range of possibilities regarding the potential effects of climate change.