Negotiators from 196 countries are seeking an accord that reduces man-made emissions to limit rising sea levels and increasingly extreme weather that is already threatening populations around the world.
Obama needs to reassure leaders that the U.S. can deliver on its own commitments, despite opposition from Congressional Republicans.
U.N. Secretary-General Ban Ki-moon is meeting French President Francois Hollande on Sunday morning to discuss the talks. The president will meet on the sidelines with the leaders of China and India.
Security is extra high in the wake of the Paris attacks.
