By withdrawing from the Paris accord, the United States—the second-largest global emitter—could undercut collective efforts to reduce emissions, the transition to renewable energy sources, and lock in future climate measures. In short, the US pulling out of the Paris Climate Accord could cause a health emergency in the United States if nothing is done. The political impact is devastating. ... They urged all their allies to speed up efforts to combat climate change and said they would do more to help developing countries adapt.