Marine biologist who challenged the idea that humans could master nature with chemicals, bombs, and space travel. Her 1962 book on the dangers of DDT galvanized a national conversation about pesticides and ecology and is widely credited with launching the modern environmental movement.
Long-time conservationist who proposed a national environmental "teach-in" in September 1969. His idea became the first Earth Day on April 22, 1970 — possibly the largest single demonstration in U.S. history.
Harvard graduate student tapped by Senator Nelson to organize Earth Day. He built a staff of 85 and coordinated events across 2,000 colleges, 10,000 K–12 schools, and most major U.S. cities.
Transformed the Sierra Club from a hiking society into a national lobbying force. Led the fight to stop dams at Dinosaur National Monument and the Grand Canyon; founded Friends of the Earth, 1969.
Sworn in December 1970 to build the new Environmental Protection Agency from scratch. Within months he had moved aggressively against polluters, sued three of America's largest cities, and banned DDT in 1972.
Forester and ecologist whose 1949 book introduced the "land ethic" — the idea that humans owe moral obligations to the soil, water, plants, and animals around them. A foundational text reread throughout the 1960s.
Cell biologist who put fallout, pollution, and the science of ecology on the public agenda. His Baby Tooth Survey proved nuclear fallout was reaching children through milk; Time put him on its cover in 1970 as "the Paul Revere of Ecology."
If the modern environmental movement has a founding text, it is Rachel Carson's Silent Spring, published September 27, 1962. Carson did not start the movement single-handedly, but she gave it its language, its scientific authority, and its most enduring image — a spring without birdsong.
Carson trained as a marine biologist and worked for years at the U.S. Fish and Wildlife Service. In 1957 she received a letter from a friend describing songbirds dying in a yard recently sprayed with DDT — the pesticide developed in the 1930s to kill mosquitoes.1
Investigating, Carson discovered that DDT was not staying where it was sprayed. It was traveling through soil and water, accumulating in plants and animals, and concentrating up the food chain. It was killing birds and fish and quietly disrupting reproduction in many more species.
Silent Spring was serialized in The New Yorker in June 1962 and published as a book that September. The chemical industry mobilized to discredit it; Carson was dismissed as a "hysterical woman" and worse. President Kennedy ordered his Science Advisory Committee to investigate her claims. The committee's 1963 report largely vindicated her.1
Carson testified before Congress in June 1963, already gravely ill with cancer. She died in April 1964, less than two years after Silent Spring's publication. DDT was banned in the United States in 1972 — eight years after her death and ten years after the book that made the ban possible.
"There was once a town in the heart of America where all life seemed to live in harmony with its surroundings."
"Then a strange blight crept over the area and everything began to change. … There was a strange stillness. The birds, for example — where had they gone?"
"It was a spring without voices. On the mornings that had once throbbed with the dawn chorus of robins, catbirds, doves, jays, wrens, and scores of other bird voices there was now no sound; only silence lay over the fields and woods and marsh."
"No witchcraft, no enemy action had silenced the rebirth of new life in this stricken world. The people had done it themselves."
Gaylord Nelson said he became a conservationist "by osmosis," having grown up in the small town of Clear Lake, Wisconsin.2 He was governor of Wisconsin before he came to the Senate in 1963, and conservation was his signature issue throughout his career — he pushed to protect the Appalachian Trail, to ban DDT, and to guarantee clean air and clean water. For years he tried to persuade Presidents Kennedy and Johnson to make environmental protection a national priority. They listened politely; little changed.
In August 1969, flying to a speech in California and reading about anti-war "teach-ins" on college campuses, Nelson had an idea: what if a single day were set aside, nationwide, for Americans to learn about the environment? His goal, he later said, was "to get a nationwide demonstration of concern for the environment so large that it would shake the political establishment out of its lethargy."2
He announced the idea on September 9, 1969, in a speech to a small conservation group in Seattle. The New York Times ran it on the front page. Letters poured into his office. He hired a 25-year-old Harvard graduate student named Denis Hayes to coordinate it nationally and gave him a budget of $125,000. Hayes built a staff of 85.
The first Earth Day was April 22, 1970. By some estimates, more than 20 million Americans took part — gathering in schools, churches, parks, and on city streets in what may have been the largest single demonstration in the nation's history.1
"It worked because of the spontaneous response at the grassroots level. We had neither the time nor resources to organize 20 million demonstrators … Earth Day organized itself." — Senator Gaylord Nelson
Within months of Earth Day, Congress passed the Clean Air Act of 1970 and the National Environmental Policy Act took effect; in December, the EPA opened its doors. Nelson received the Presidential Medal of Freedom in 1995 in recognition of Earth Day's lasting impact.
Denis Hayes was a Stanford graduate, a former student-body president, and a first-year graduate student at Harvard's Kennedy School when Gaylord Nelson hired him in late 1969 to coordinate Earth Day. He dropped out of school to take the job.
Hayes assembled a small headquarters office in Washington, recruited regional coordinators on hundreds of college campuses, and worked the phones to schools, churches, civic groups, and labor unions. By April 22, 1970, Earth Day had events in roughly 2,000 colleges and universities, 10,000 K–12 schools, and most U.S. cities.
Hayes has continued to organize Earth Days ever since — globally in 1990 (an estimated 200 million participants in 141 countries) and, on the 50th anniversary in 2020, online during the early months of the COVID-19 pandemic.
When David Brower became the Sierra Club's first executive director in 1952, the organization was an 80-year-old hiking and outings club with about 7,000 members. By the time the Sierra Club fired him in 1969, it had 77,000 members and was the most aggressive conservation lobby in Washington.1
Brower led the successful 1956 fight to keep dams out of Dinosaur National Monument and the celebrated 1966 campaign — including full-page New York Times ads asking, "Should we also flood the Sistine Chapel so tourists can get nearer the ceiling?" — that stopped the Bureau of Reclamation from damming the Grand Canyon.
After leaving the Sierra Club, Brower founded Friends of the Earth in 1969, an international organization that became a fixture of the global environmental movement.
The major environmental organizations of this era — the Wilderness Society, the Sierra Club, the National Audubon Society, the Nature Conservancy, the National Wildlife Federation, and the National Parks and Conservation Association — all "predated the rise of modern ecological science," in Brinkley's words, "but all of them entered the twenty-first century reenergized and committed to the new concepts of environmentalism."1
President Nixon's Reorganization Plan No. 3 of 1970 consolidated environmental responsibilities scattered across more than a dozen federal offices into a single new agency: the Environmental Protection Agency. The EPA officially opened on December 2, 1970.3
To run it, Nixon chose William Ruckelshaus, a 38-year-old assistant attorney general who had been deputy attorney general of Indiana. Ruckelshaus understood that for the EPA to mean anything, it had to immediately demonstrate it would enforce the law.
Within his first weeks he sued three of America's largest cities — Atlanta, Cleveland, and Detroit — for violating water-pollution standards. In June 1972 he announced the long-debated federal ban on DDT, vindicating Rachel Carson exactly a decade after Silent Spring.
Ruckelshaus served twice as EPA Administrator (1970–73 and 1983–85). His decisive early actions established the agency's credibility and set the template for federal environmental enforcement that endures today.
Aldo Leopold died in 1948 fighting a brush fire, but he is impossible to leave off this list. His 1949 book A Sand County Almanac — published posthumously — became a touchstone for environmental thinking in the 1960s, when copies passed from hand to hand on college campuses and in Sierra Club chapter meetings.
Leopold's central idea was the land ethic: that humans have moral obligations not just to other people but to "the soils, waters, plants, and animals" of the places we live. He argued that ethics had historically expanded — from family to tribe to nation — and that the next expansion was outward, to the rest of the natural community.1
"We abuse land because we regard it as a commodity belonging to us. When we see land as a community to which we belong, we may begin to use it with love and respect." — Aldo Leopold, A Sand County Almanac, 1949
The science of ecology gave the 1960s movement its facts. Leopold's land ethic gave it its conscience.
1. Alan Brinkley, American History: Connecting with the Past, 14th ed., ch. 30, pp. 847–850.
2. Nelson Earth Day Network, "Tracing Earth Day's Origins."
3. U.S. Environmental Protection Agency, "Origins of the EPA."
If Rachel Carson gave the movement its conscience, Barry Commoner gave it a scientist who would shout from the rooftops. A Washington University cell biologist, Commoner became one of the most visible public faces of ecology in America — so much so that Time magazine put him on its cover in 1970 and called him "the Paul Revere of Ecology."4
His breakthrough as an activist came not from pollution but from the bomb. In the late 1950s, Commoner helped found the Greater St. Louis Citizens' Committee for Nuclear Information, which organized the Baby Tooth Survey — collecting hundreds of thousands of children's baby teeth and measuring the radioactive isotope strontium-90 they contained.
The results were alarming: fallout from atmospheric nuclear-weapons tests was drifting down onto pastures, concentrating in cows' milk, and ending up in the bones and teeth of American children. Children born in 1963 carried strontium-90 levels in their teeth roughly 50 times higher than children born before large-scale testing began. The survey turned an invisible danger into hard data and helped build the public pressure behind the 1963 Partial Nuclear Test Ban Treaty.
Commoner spent the rest of his career insisting that pollution, energy, and poverty were a single interlocking problem. His famous "four laws of ecology" — beginning with "Everything is connected to everything else" — popularized for millions the same idea of interrelatedness that ran through Carson's and Leopold's work.
"Everything is connected to everything else. Everything must go somewhere. Nature knows best. There is no such thing as a free lunch." — Barry Commoner, The Closing Circle, 1971
4. "Environment: Paul Revere of Ecology," Time, Feb. 2, 1970; "Barry Commoner: Scientist, Activist, Radical Ecologist," Climate & Capitalism; "Baby Tooth Survey," Wikipedia.