On September 3rd, 2016, the United States and China formally joined the Paris Agreement on climate change. The announcement came at a bilateral meeting between President Barack Obama and President Xi Jinping on Saturday, ahead of the upcoming G20 summit in Hangzhou, China. The announcement provides a major boost in the momentum behind the effort needed for the Paris Agreement to enter into force, which is likely to happen before the end of 2016. In order for the agreement to enter into force, a total of 55 countries representing 55% of global GHG emissions must join. China and the United States are the world’s two largest emitters of greenhouse gases, accounting for a combined 38% of global emissions.