Meeting the goals of the Paris Agreement could save about a million lives a year worldwide by 2050 through reductions in air pollution alone. The latest estimates from leading experts also indicate that the value of health gains from climate action would be approximately double the cost of mitigation policies at global level, and the benefit-to-cost ratio is even higher in countries such as China and India. A WHO report launched at the United Nations Climate Change Conference (COP24) in Katowice, Poland highlights why health considerations are critical to the advancement of climate action and outlines key recommendations for policy makers.