(NEXSTAR) – The founders of Earth Day had a clear vision in mind when planning the first national observance. What they didn’t have was a catchy name.

The origins of the annual event can be traced back to the late 1960s following a decade of increasing concern for environmental issues that threatened the health and safety of future generations. EarthDay.Org, the nonprofit organization that coordinates Earth Day’s global events, credits Rachel Carson and her 1962 best-selling book “Silent Spring” with drawing widespread attention to some of those issues, particularly the negative impact of pollution and the then-pesticide industry.

Carson’s book “represented a watershed moment,” EarthDay.org writes on its official site. But it wasn’t until January 1969 — following the devastating effects of the Santa Barbara oil spill, which dumped well over 3 million gallons of crude oil into the Santa Barbara Channel — that serious action was taken.

Upon learning of the spill, U.S. Sen. Gaylord Nelson, of Wisconsin, was inspired to coordinate a national campaign to further promote awareness of the growing environmental movement. Together with Republican Congressman Pete McCloskey, Nelson began efforts to plan “teach-ins” at college campuses across the country, hiring Harvard grad student Denis Hayes to help organize the first nationwide teach-in on April 22, 1970.

And what was the leading idea for the event’s name? The “Environmental Teach-In.”

By early 1970, the idea for the Environmental Teach-In — despite its somewhat dull name — drew the attention of prominent ad writer Julian Koenig, who was responsible for penning the copy for the Volkswagen Beetle’s “Think Small” campaign over a decade earlier.

Hayes would later claim that Koenig reached out to his team in early January to offer his services, and they gladly accepted.  

Within a couple of days, Koenig had presented several ideas for newspaper advertisements.

“He offered a bunch of possible names — Earth Day, Ecology Day, Environment Day, E Day — but he made it quite clear that we would be idiots if we didn’t choose Earth Day,” Hayes once wrote in a letter sent to Koenig’s daughter Sarah Koenig (producer and host of the “Serial” podcast), as The New York Times previously reported in 2014. Coincidentally, April 22 was Koenig’s birthday, and Koenig also liked how “Earth Day” rhymed with “birthday,” Koenig reportedly said.

The group took Koenig’s advice. On Jan. 18, 1970, a full-page ad promoting Earth Day appeared in The New York Times.

The name has stuck ever since.

The organization that coordinates Earth Day has also changed its own name over the years — from the Earth Day Network to EarthDay.org — but one thing that hasn’t changed is its mission. EarthDay.org is continuing to support greener initiatives and encourage activism.

More information on Earth Day 2023 and where to find a local event can be found at EarthDay.org.