Upon rejoining, the U.S. will likely be expected to provide an updated climate target since the Obama administration’s goal and a plan to reduce domestic emissions from the power and energy sector. The U.S. is the world’s second largest emitter of greenhouse gases behind China, and is seen as key in the global effort to avoid the worst impacts of climate change.
“Since the U.S. has one of the biggest economies in the world and has contributed the most to climate change, it is incredibly important that the U.S. return to the Paris agreement,” said Cornell University climate scientist Natalie Mahowald, a lead author of the 2018 U.N. report on climate change.
https://www.cnbc.com/2020/11/20/biden-to-rejoin-paris-climate-accord-heres-what-happens-next-.html