"What better time to have a day for Earth than Mother Nature's first day of spring?" he said. The idea came to him as he thought about Stonehenge, a structure in Britain believed to have been used by prehistoric tribes to mark the equinoxes and solstices of the four seasons.
McConnell said the moment he told his wife of his inspiration was memorable because, "the whole house started shaking. We were having an earthquake."
The first Earth Day was held March 21, 1970, in San Francisco, and the United Nations continues to observe it on the vernal equinox, according to McConnell.
The former newspaper publisher said Day observations in April are more common in the United States.
On whatever date it is celebrated, McConnell said, "We want individuals and institutions to think and act as trustees of Earth in ecology, economics and ethics, making choices that will eliminate poverty, pollution and violence."
McConnell told an audience of about 100 that he has been involved in environmental and peace issues for more than 40 years. As the publisher of a North Carolina weekly newspaper in 1957, he said he gained some international recognition following the launching of the Soviet Sputnik satellite by proposing the launch of a Star of Hope satellite that would be visible from Earth.
The satellite never got off the ground, but he's hopeful the idea can be resurrected.
"Maybe somebody like (Microsoft founder) Bill Gates will get behind it," he said.
McConnell was kept busy for more than an hour after his speech, signing copies of his "Earth Magna Charta," a document stating his philosophy on sharing the Earth's resources.