In 2018, WMO and WHO signed a Collaboration Framework on Climate, Environment and Health, committing WHO and WMO to work more closely together to protect health from the risks of extreme weather and climate events, pollution of air and water, and global climate change. This Master plan is a three-part strategy to operationalize the objectives of the WHO-WMO Collaboration Framework on Climate, Environment and Health, and the eighteenth session of the World Meteorological Congress Resolution 33 (Cg-18).