Spurring the Rest of the Planet

The recent joint announcement of national emission reduction targets by China and the United States was a great diplomatic breakthrough and represents the beginning of the realization of the promise offered by the 2011 U.N. climate meeting in Durban, boding well for a productive new path forward for international climate negotiations.

The announced China-U.S. quantitative contributions are themselves significant. For China, capping its emissions by 2030 (at the latest), plus increasing its non-fossil energy generation to 20 percent of its total by the same year, will require very aggressive measures, according to a recent MIT analysis. For the United States, cutting its emissions by 26–28 percent below the 2005 level by 2025 means doubling the pace of cuts under the country's previous international commitment.

But more importantly, China's and America's commitments create a sufficient foundation for meaningful future steps among the entire global community, beginning with the 2015 Paris agreement that is being drafted in Lima over the next two weeks. With the announced Chinese and American national determined contributions, the future Paris agreement would include countries that together account for more than 40 percent of global carbon emissions. With Europe already on board, the total amounts to more than 50 percent of the world's emissions.

It will not be long before the other industrialized countries announce their own contributions, and the pressure is now on the other large, emerging economies—India, Brazil, Korea, South Africa, Mexico and Indonesia—to step up too. Some countries may well announce their contributions in Lima, but all are scheduled to announce at least by the end of the first quarter of 2015. By that point, we might well look back and see that the recent U.S.-China commitment was one of the most important moments in more than two decades of international climate negotiations.

Robert Stavins is Albert Pratt professor of business and government and director of the Environmental Economics Program at the Harvard Kennedy School.