The U.S. forfeited leadership in the global effort to combat climate change when it left the Paris Agreement. Now back, will the U.S. resume its former role?---On Friday, February the 19th, the United States officially rejoined the Paris Climate Agreement, bringing to an end an extended period of national disengagement from the global effort to address climate change. As the largest historic emitter of greenhouse gasses, and today’s second largest emitter behind China, U.S. engagement is critical to the global effort to address climate change.Yet the climate framework that the U.S. abandoned under the Trump administration looks different today. The U.S., rather than being a clear leader on climate issues, is embarking on an effort to rebuild trust and reassure the world that it will remain committed to addressing climate change, while the relative influence in of China, Europe and other regions has grown in global climate dialogue.Joanna Lewis, Director of the Science, Technology and International Affairs Program at Georgetown University, discusses how the Paris Climate framework, and the global hierarchy of climate leadership, has changed in recent years. She also looks at the barriers that U.S.-China trade tensions may present to climate cooperation as the U.S. rejoins the Paris process.  Joanna Lewis is Director of the Science, Technology and International Affairs Program at Georgetown University. She is also a Strategic Advisor to the China Energy Group at Lawrence Berkeley National Lab.Related ContentInnovation in Isolation: Islands and the Energy Transition https://kleinmanenergy.upenn.edu/research/publications/innovation-in-isolation-islands-and-the-energy-transition/ It’s Ideology Stupid: Why Voters Still Shun Carbon Taxes https://kleinmanenergy.upenn.edu/research/publications/its-ideology-stupid-why-voters-still-shun-carbon-taxes/