On Dec. 12, the 2015 United Nations Climate Change Conference in Paris ended with the first climate change agreement in which the representatives of all 195 nations have agreed to reduce greenhouse gas emissions. The deal comes after more than 20 years of deliberation following the 1992 UN Framework Convention on Climate Change (UNFCCC) treaty, which set goals and procedures for signatory nations to contain and reduce carbon emissions.

We discussed the agreement with two Princeton University researchers who attended the Paris climate talks: Michael Oppenheimer, the Albert G. Milbank Professor of Geosciences and International Affairs and director of the Program in Science, Technology and Environmental Policy; and Denise Mauzerall, professor of civil and environmental engineering and public and international affairs.