President Obama spent a frenzied day in ad-hoc meetings with leaders from several nations on December 18 to try and salvage the fractious two week talks.
The United Nations talks ended with a limited, non-binding accord in which many countries -- including China, the world's largest emitter -- will commit to implementing their national emissions-curbing pledges. But Obama has acknowledged the accord he helped broker will not generate sufficient worldwide greenhouse gas cuts.
It remains to be seen whether the underwhelming outcome will help or hinder slow-moving Senate efforts to pass climate legislation.
The unwieldy talks led several analysts -- such as Harvard's Robert Stavins -- to suggest it's time to look outside the U.N. process for global progress on emissions reductions.