Interview with interviews Michael Oppenheimer, Professor of Geosciences and International Affairs and the High Meadows Environmental Institute at Princeton University. Oppenheimer describes the three-way nature of his work at Princeton, between the School of Public and International Affairs and the Science, Technology, and Environmental Policy program. He describes the possibilities for climate change policy in the transition from Presidents Trump to Biden, and he discusses the moral dimension to climate change diplomacy and what the Global North owes the Global South. Oppenheimer recounts his childhood in Queens, the opportunities that allowed him to enroll at MIT at age 16, and his decision to focus on chemistry and to become involved in political activity in the 1960s. He explains his decision to go to the University of Chicago for graduate school, where he studied under the direction of Steve Berry on low-temperature spectroscopy of alkali halides. Oppenheimer describes his postdoctoral research at what would soon become the Center for Astrophysics at Harvard to work on astrophysics from an atomic and molecular perspective and on the chemistry of comets. He explains how the acidification issue in the Adirondack Lakes serves as an entrě to his interests in environmental policy and how this led to his work for the Environmental Defense Fund. Oppenheimer describes his work on the linearity question and why it is relevant for understanding carbon emissions and his advocacy work on the Clean Air Act. He explains the early science that concluded that even a few degrees of warming would be globally catastrophic, and the early signs that the Republican party would serve generally to block legislation to mitigate climate change. Oppenheimer discusses his involvement with international climate negotiations and policy with the IPCC and the issue of contrarianism in global warming debates. He contrasts the simplicity of the greenhouse effect with the complexity of understanding climate change, and he explains his decision to move to Princeton within the context of what he thought the Kyoto Protocol had achieved. Oppenheimer reflects on how climate change has increased in the public consciousness, and at the end of the interview, he considers early missed opportunities for more change in climate policy, and where he sees reason for both optimism and pessimism as the world faces future threats relating to climate change.