Introduction

In the late 1980s, planning began for what would become the United Nations Conference on Environment and Development in Rio de Janeiro, known informally as the Earth Summit. Scientists had called attention to the planetary-scale impacts of human activities: acid rain, ozone depletion, deforestation, biodiversity loss, and now global warming. The latter had come to public attention as the United Nations Environment Programme and the World Meteorological Society joined forces in 1988 to form the Intergovernmental Panel on Climate Change (IPCC) to evaluate the scientific evidence and suggest possible remedies. Scientists had long predicted that increased greenhouse gases from burning fossil fuels would change the chemistry of the atmosphere in ways that could affect global climate, and these predictions were apparently starting to come true. As heat waves scorched the American Midwest, world-renowned climate modeler James Hansen declared in testimony to the U.S. Congress that our Earth had entered a long-term warming trend and that human-made greenhouse gases almost surely were responsible.

1988 was also the year that George H. W. Bush was elected president of the United States, and during his election campaign, he had pledged to combat the greenhouse effect with the “White House effect” – to bring the power of the presidency to bear on the issue of global warming – and to convene a conference on global environmental issues in his first year in office. But like many campaign promises, this one went unfulfilled. One, two, and then three years went by. As June 1992 – the date of the Rio summit – approached and 108 heads of state, 2,400 representatives of nongovernmental organizations (NGOs), and more than 10,000 on-site journalists made plans to converge in Rio (along with 17,000 other individuals who would convene in a parallel NGO forum), it was unclear whether the U.S. president would even attend the meeting.