Throughout the early 20th century, concerns about the environment focused primarily on conservation and the protection of the natural world. In the early 1960s, however, environmentalists shifted their attention to man-made threats to the environment, particularly the pollution resulting from chemicals, auto emissions, oil spills, and industrial waste. The publication of Rachel Carson’s 1962 book, Silent Spring, which argued that the widespread use of pesticides, particularly DDT, imperiled both humans and songbirds, was a watershed moment. By the end of the decade, membership in both the Wilderness Society and the Sierra Club soared, and in bipartisan fashion, Congress passed the Clean Air Act (1963), the Water Quality Act (1965) and the Motor Vehicle Air Pollution Control Act (1965) in rapid succession. The widespread appeal of the environmental agenda was clear by 1970, when an estimated 20 million Americans participated in the first Earth Day events on April 22 and President Richard Nixon created the Environmental Protection Agency (EPA). Building on this momentum, Congress passed the Federal Water Pollution Control Act in 1972, the Endangered Species Act in 1973, and strengthened the Clean Air Act in bipartisan fashion.
Environmentalism became more controversial after the oil shocks of the early 1970s. It was much harder for a nation accustomed to cheap and abundant sources of fossil fuels to agree on a path forward after the 1973-74 Arab oil embargo. Although the Department of Energy was founded in 1977 to develop a national energy plan and to fund research into alternatives to fossil fuels, bipartisan support for industrial regulation and energy alternatives collapsed after the election of Ronald Reagan in 1980. As the Reagan administration rolled back environmental regulations and cut EPA funding, the environmental movement grew and splintered. Radical environmentalist groups such as Greenpeace engaged in direct-action civil disobedience campaigns against whaling, nuclear power, nuclear testing, and radioactive waste disposal. The Earth Liberation Front embraced even more extreme tactics, engaging in “eco-sabotage” to stop the clear cutting of forests or the construction of oil pipelines. By the late 1980s, the growth of the environmental justice (EJ) movement brought a racial and class dimension to eco-activism, showing how environmental pollution disproportionately affected racial minorities and poorer people, and expanding the support base of environmentalism beyond the educated white middle class.
Global issues have commanded the attention of the environmental movement since the 1990s. In 1988, NASA linked global warming, or the long-term heating of the earth’s surface, to human activity, particularly the burning of fossil fuels. Carbon emissions, acid rain, ozone depletion, and the disappearance of the rainforests became issues to be addressed on a global scale through international diplomacy. Initially a reluctant participant, the United States ratified the Montreal Protocol in 1988, which established a plan for eliminating chlorofluorocarbons; endorsed the Kyoto Protocol for reducing greenhouse gasses a decade later, though the Senate never approved it; and signed the Paris Climate Accord in 2016, before withdrawing from the agreement in 2020 and rejoining in 2021. Although the goal of protecting the planet remains popular, the lack of a bipartisan consensus about the causes of global warming and the impact of climate change has made it difficult for the United States to adopt a consistent energy policy since 2000.