The environmental movement’s past recently collided with its future. April 22 marked the 50th anniversary of the first Earth Day, a milestone for environmentalism. A few days later, a global school strike was organized by Fridays for Future, the international coalition of young people inspired by Greta Thunberg’s protests against climate change. But after months of careful planning, both occasions were upended by the COVID-19 pandemic – and went online instead.

So when social distancing measures are eased, will protest return to the streets, or do these events mark a turning point?

In 1970, an estimated 20 million Americans (10% of the US population at the time) participated in the first Earth Day. Back then, US senator Gaylord Nelson conceived of a national “teach-in” to raise environmental awareness and recruited Harvard law student Denis Hayes to organize the event.

Teach-ins had emerged in the mid-1960s as a hybrid of student sit-ins and informal lectures in opposition to the Vietnam War. Rather than going on strike, teachers and students occupied classrooms instead. According to environmental historian Adam Rome, 1,500 universities and 10,000 schools held Earth Day teach-ins in April 1970, “nurturing a generation of activists.”

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