The energy crisis drove home the realization that the earth’s resources are not limitless. Such a notion was also at the heart of the era’s revival of environmentalism. The environmental movement was an offshoot of sixties activism, but it had numerous historical precedents: the preservationist, conservationist, and wilderness movements of the late nineteenth century; the conservationist ethos of the New Deal; and anxiety about nuclear weapons and overpopulation in the 1940s. Three of the nation’s leading environmental organizations — the Sierra Club, the Wilderness Society, and the Natural Resources Council — were founded in 1892, 1935, and 1942, respectively. Environmental activists in the 1970s extended the movement’s historical roots through renewed efforts to ensure a healthy environment and access to unspoiled nature (Thinking Like a Historian).

The movement had received a hefty boost back in 1962 when biologist Rachel Carson published Silent Spring, a stunning analysis of the pesticide DDT’s toxic impact on the human and natural food chains. A succession of galvanizing developments followed in the late 1960s. The Sierra Club successfully fought two dams in 1966 that would have flooded the Grand Canyon. And in 1969, three major events spurred the movement: an offshore drilling rig spilled millions of gallons of oil off the coast of Santa Barbara; the Cuyahoga River near Cleveland burst into flames because of the accumulation of flammable chemicals on its surface; and Friends of the Everglades opposed an airport that threatened plants and wildlife in Florida. With these events serving as catalysts, environmentalism became a certifiable mass movement on the first Earth Day, April 22, 1970, when 20 million citizens gathered in communities across the country to express their support for a cleaner, healthier planet.

Environmental Protection Agency Earlier that year, on the heels of the Santa Barbara oil spill, Congress passed the National Environmental Policy Act, which created the Environmental Protection Agency (EPA). A bipartisan bill with broad support, including that of President Nixon, the law required developers to file environmental impact statements assessing the effect of their projects on ecosystems. A spate of new laws followed: the Clean Air Act (1970), the Occupational Health and Safety Act (1970), the Water Pollution Control Act (1972), and the Endangered Species Act (1973).

The Democratic majority in Congress and the Republican president generally found common ground on these issues, and Time magazine wondered if the environment was “the gut issue that can unify a polarized nation.” Despite the broad popularity of the movement, however, Time’s prediction was not borne out. Corporations opposed environmental regulations, as did many of their workers, who believed that tightened standards threatened their jobs. “IF YOU’RE HUNGRY AND OUT OF WORK, EAT AN ENVIRONMENTALIST,” read one labor union bumper sticker. By the 1980s, environmentalism starkly divided Americans, with proponents of unfettered economic growth on one side and environmental activists preaching limits on the other.

Nuclear Power An early foreshadowing of those divisions came in the brewing controversy over nuclear power. Electricity from the atom — what could be better? That was how Americans had greeted the arrival of power-generating nuclear technology in the 1950s. By 1974, U.S. utility companies were operating forty-two nuclear power plants, with a hundred more planned. Given the oil crisis, nuclear energy might have seemed a godsend; unlike coal- or oil-driven plants, nuclear operations produced no air pollutants.

Environmentalists, however, publicized the dangers of nuclear power plants: a reactor meltdown would be catastrophic, and so, in slow motion, would the dumping of the radioactive waste, which would generate toxic levels of radioactivity for hundreds of years. These fears seemed to be confirmed in March 1979, when the reactor core at the Three Mile Island nuclear plant near Harrisburg, Pennsylvania, came close to meltdown. More than 100,000 people fled their homes. A prompt shutdown saved the plant, but the near catastrophe enabled environmentalists to win the battle over nuclear energy. After the incident at Three Mile Island, no new nuclear plants were authorized, though a handful with existing authorization were built in the 1980s. Today, nuclear reactors account for 20 percent of all U.S. power generation — substantially less than several European nations, but still fourth in the world.