Health leaders are warning governments of “unimaginable” health consequences from the climate crisis if world leaders don’t take decisive action to decarbonize. This week at the U.N. climate summit in Glasgow, the Global Climate and Health Alliance presented a letter to the COP26 president signed by 46 million health workers who are calling for global climate action on health. Meanwhile, a delegation of mothers from Brazil, Britain, India, Nigeria, Poland and South Africa attended COP26 to deliver their own letter to the summit’s president that was signed by about 500 parent groups from 44 countries and calls for limits on air pollution. We go inside COP26 to speak with Jeni Miller, executive director of the Global Climate and Health Alliance and co-chair of the World Health Organization’s Civil Society Working Group to Advance Action on Climate Change and Health, and medical student Amit Singh, a member of Students for Global Health. “Climate change is a threat multiplier,” says Miller. “Increasingly, we’re recognizing that we can’t care for the patients and the communities that we serve if we don’t step outside the clinic and address this driver of health impacts, which is climate change.”