Why is Earth Day on April 22?

April 22 is the date of Earth Day in part because of Arbor Day, an earlier observance. The focus of Earth Day 2021 is ‘Restore Our Earth.’

Black and white photo of gigantic crowd in 1970 garb and hair.

An estimated 7,000 demonstrators in Philadelphia on Earth Day, April 22, 1970. Image via AP Photo.

The first Earth Day – April 22, 1970 – is sometimes said to have marked the beginning of the modern environmental movement. It predates the U.S. Environmental Protection Agency, for example. It’s hard to imagine it now, but the first Earth Day was a revelation to many, a way not only of raising consciousness about environmental issues but also of bringing together separate groups that had been fighting separately against issues including oil spills, pollution from factories and power plants, raw sewage, toxic dumps, pesticides, the loss of wilderness, air pollution and more. At the first Earth Day in 1970, an estimated 20 million Americans took to the streets, parks, and auditoriums to demonstrate for a healthy environment and to participate in teach-ins.

The April 22 date was selected in part because it fell between colleges’ spring break and final exams, and also from the observance of Arbor Day, which began in Nebraska in 1872, a day when people are encouraged to plant trees.

Since 1970, many important environmental events have happened on Earth Day, including the signing of the Paris Agreement on April 22, 2016. This year, the Biden administration has decided to convene a global climate summit on Earth Day.

Parallel to the global climate summit, EarthDay.org will have its second Earth Day Live digital event, with a focus on Restore Our Earth. The global show begins at noon EDT (16:00 UTC; translate UTC to your time). Watch here. Scroll down on EarthDay.org to find more Earth Day events from around the world.

Man and woman in front of Environmental Teach-In poster with groovy 1960s style lettering.

In the late 1960s, there were love-ins, be-ins … and, like the first Earth Day, teach-ins. Here are two organizers of the first Earth Day in 1970. Image via AP/ Lincoln&Rose.

Wisconsin Senator Gaylord Nelson is widely credited with suggesting the first Earth Day on April 22. The date was selected in part with college campuses in mind; April 22 fell between spring break and final exams.

The date of the first Earth Day also stemmed from a much earlier observance: Arbor Day, which began in Nebraska in 1872. The most common practice on Arbor Day was tree-planting. J. Sterling Morton was a Nebraska pioneer, a writer and editor for Nebraska’s first newspaper, and later secretary of the Nebraska Territory. He advocated planting trees in what was then a dusty and treeless prairie. At a meeting of the State Board of Agriculture in January 1872, Morton proposed that Nebraska citizens set aside April 10 as a day to plant trees. He suggested offering prizes as incentives for communities and organizations that planted the most trees. It’s said that Nebraskans planted about one million trees on that first Arbor Day in 1872.

Ten years later, in 1882, Nebraska declared Arbor Day as a legal holiday and the date was changed to Morton’s birthday, April 22. Arbor Day grew to become a national observance.

It seemed natural to schedule April 22, 1970 – Arbor Day – as the first Earth Day. Today, a common practice in celebration of Earth Day is still to plant new trees.

Men planting a tree with girls in white lined up in background some year around 1900.

Here is Arbor Day at N.Y. Public School #4, 173rd St. & Fulton Ave., New York. Date unknown. Via Library of Congress.

Kathleen Rogers is a former environmental attorney who has led the Earth Day Network since 2001. She’s a frequent commentator on environmental issues in the media (CNN, Fox News, NPR, Time, Washington Post, Los Angeles Times). She wrote of Earth Day:

Earth Day is now a global event each year, and we believe that more than 1 billion people in 192 countries now take part in what is the largest civic-focused day of action in the world.

It is a day of political action and civic participation. People march, sign petitions, meet with their elected officials, plant trees, clean up their towns and roads. Corporations and governments use it to make pledges and announce sustainability measures. Faith leaders, including Pope Francis, connect Earth Day with protecting God’s greatest creations, humans, biodiversity and the planet that we all live on.

Want to participate? Sign up to join the Earth Day Movement

Bottom line: Why do we celebrate Earth Day on April 22? The date stems from an earlier observance, Arbor Day. The focus of Earth Day 2021 is “Restore Our Earth.”

Deborah Byrd