On September 3, 2016, the United States and China jointly announced their formal ratification of the Paris climate agreement. As the two largest emitters of greenhouse gases, their decision was widely seen as crucial to the accord’s success. The move signaled a shared commitment to limiting global temperature increases and promoting low-carbon development. Ratification encouraged other countries to complete their own approval processes, helping the agreement enter into force later that year. It also marked a period of closer U.S.–China cooperation on climate issues, even as other aspects of the relationship remained competitive.
