It was in the same year Jimi Hendrix died, the Beatles produced their last album and Simon & Garfunkel released “Bridge Over Troubled Water” that Earth Day emerged as one of the world’s first environmental campaigns.

Capitalizing on an emerging consciousness and channeling the energy of the anti-war protests, Earth Day 1970 thrust environmental concerns into the fray.

The idea came to founder Gaylord Nelson, then-U.S. senator from Wisconsin, after he witnessed the aftermath of the 1969 oil spill in Santa Barbara, Calif. It was the largest oil spill in U.S. waters at the time, and spurred the senator into action.

On April 22, 1970, he galvanized 20 million Americans from coast to coast to take to streets, parks and auditoriums to demonstrate for a healthy, sustainable environment. Earth Day was born.

The initial demonstration spurred both the creation of the Environmental Protection Agency and the passage of the Clean Air, Clean Water and Endangered Species Acts.

Earth Day went global two decades later with a massive campaign mobilizing 200 million people in 141 countries. That effort, too, proved monumental. It kickstarted recycling programs worldwide and paved the way for the 1992 United Nations Earth Summit in Rio de Janeiro.

More than four decades later, Earth Day Network -- a group founded by the organizers of the first Earth Day to coordinate the annual day of action as well as year-round advocacy, education and public policy campaigns to protect the environment -- expects more than one billion people from 192 nations to participate.

Kathleen Rogers, president of Earth Day Network, said this year’s theme would put a face to climate change.

“Many people think climate change is a remote problem, but the fact is that it’s already impacting real people, animals and beloved places all over the world, and these Faces of Climate Change are multiplying every day,“ she said. “Fortunately, other Faces of Climate Change are also multiplying every day: those stepping up to do something about it.”

Rogers noted that, for Earth Day 2013, the organization will “bring our generation’s biggest environmental challenge down to size -- the size of an individual faced with the consequences.”

Over the past two months, Earth Day Network has collected images of people and places directly affected or threatened by global warming for its new project. On Monday, it will show those images at community events across the globe, “including next to federal government buildings in countries that produce the most carbon pollution.”

Organizers have asked participants in Earth Day 2013 to use Facebook, Instagram and Twitter (#FaceOfClimate) to spread awareness.

“The Face of Climate Change … will unite the myriad Earth Day events around the world into one call to action at a critical time,”  Franklin Russell, director of Earth Day, at Earth Day Network, said.

Russell noted that 2012 was the year of many climate change milestones, including the hottest year on record in the U.S. The World Meteorological Organization announced last year that the first decade of the 21st century was the hottest on record for the entire planet.

Yet, despite these milestones, Russell believes talks about climate change stagnated as many became apathetic or saw the problem simply as the new normal. He said he has hope that U.S. President Barack Obama’s high-profile promise to tackle climate change in his second term will come true.

He asked all participants in Earth Day 2013 to “call on our leaders to act boldly together, as we have, on this critical issue.”

As Earth Day has proven in the past, a big call to action is often met with a big response.