The United States was also expected to announce that it was formally joining the Paris Agreement in advance of the Group of 20 summit that starts Sunday in the eastern Chinese city of Hangzhou. Obama landed in Hangzhou Saturday and was scheduled to speak about climate change shortly afterward.
China is the top emitter of man-made carbon dioxide emissions, and the United States is second. Together, they produce 38 percent of the world's man-made carbon dioxide emissions.
Both were key to getting an agreement in Paris last year. To build momentum for a deal, they set a 2030 deadline for emissions to stop rising and announced their "shared conviction that climate change is one of the greatest threats facing humanity."
The agreement's long-term goal is to keep global warming below 2 degrees Celsius (3.6 degrees Fahrenheit), compared with pre-industrial times. It has an aspirational goal of limiting the temperature rise to 1.5 degrees C (2.7 degrees F). Temperatures have already risen by almost 1 degree C (1.8 degrees F) since the industrial revolution.
Under the Paris Agreement, countries are required to set national targets for reducing or reining in their greenhouse gas emissions. Those targets aren't legally binding, but countries must report on their progress and update their targets every five years. The first cycle begins in 2020. Only developed countries are expected to slash their emissions in absolute terms. Developing nations are "encouraged" to do so as their capabilities evolve over time.
SOURCES - New York Times