Early warning systems (EWS) are an adaptive measure for climate change, using integrated monitoring, forecasting and communication systems to help communities prepare for and manage hazardous climate-related events. Successful EWS save lives and jobs, land and infrastructure and support long-term sustainability and disaster risk reduction. Early warning systems assist public officials and administrators in their planning, saving money in the long run and protecting economies and natural assets. This brief presents some of the innovative EWS initiatives that the UN, working in diverse partnerships, has introduced in vulnerable areas around the world.