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The Union Oil Company’s oil spill in February 1969—which covered 800 square miles of ocean and shore in Santa Barbara, California, in crude oil—was widely televised, and it inspired then-Senator Gaylord Nelson of Wisconsin to organize the first Earth Day in 1970. That same year, the National Environmental Policy Act of 1969 went into effect, requiring every major decision of the federal government to be evaluated for its impact on the environment.

Photo by Vernon Merritt III, The LIFE Picture Collection/Getty Images

51 years of environmental victories, in photos

On Earth Day, we look at annual conservation milestones since the first official day celebrating our planet in 1970.

BySydney Combs, Brian Clark Howard, and Lori Cuthbert

April 21, 2021

Another year, another Earth Day to add to the 50 years of environmental successes since the first was celebrated in 1970. Over the decades, momentum behind environmental conservation has ebbed and flowed, but each year has brought at least some signs of environmental progress, somewhere in the world. The pictures here symbolize that hopeful counterpoint—at the rate of one win per year—to the mounting challenges.

To mark this year’s anniversary, we note the clean skies the world experienced as a result of the coronavirus pandemic. As people holed up at home and vehicles vacated the roads, annual global energy-related emissions fell 5.8 percent, more than in any year since WWII, according to the International Energy Agency.

The cleaner air was just one of the things about this strange and terrible year that made many people think harder about how humans manage the global environment—and about the possibility and urgent need of doing better.