"Making Global Warming Green: Climate Change and American Environmentalism, 1957-1992" investigates how global climate change became a major issue in American environmental politics during the second half of the 20th Century. The dissertation focuses on the complex institutional, political, and professional relationships between scientists studying climate and America's professional environmentalists during this tumultuous period. Throughout the early history of global warming, the geographical and chronological scales of climatic and atmospheric change transcended the existing legal and regulatory mechanisms of American environmental politics. Only scientists had the technology and expertise to recognize threats to these novel components of the environment, and their exclusive access all but forced them into a prominent role as environmental advocates. But scientists' particular forms of advocacy often reflected the values and interests of their disciplines more than they did the middle-class quality-of-life concerns at the center of the mainstream American environmental movement. Scientists framed climate change in terms of development and natural resources, and they sought to influence elites in government and at international scientific organizations more than they worked to mobilize the American public. As American environmentalists began to take up the fight against global warming in the 1980s and '90s, they too found themselves trading in the language of scientific consensus and government-sponsored global solutions rather than the locally focused, middle-class consumer values originally at the heart of the movement. More than just a political history of global warming, this research presents a new history of American environmentalism that takes into account the science and politics of an issue that has emerged in the twenty-first century as one of our greatest challenges.