What was the name of Earth Day Network's campaign billed as the world's largest environmental service campaign?

Earth Day Network’s campaign billed as the world’s largest environmental service campaign was A Billion Acts of Green.

The campaign began in 2010, around the 40th anniversary of the first Earth Day. It invited individuals, businesses, governments, schools, and civic organizations to register practical environmental actions, from recycling and energy conservation to tree planting and community projects.

The campaign’s goal was to show that millions of small actions could collectively create measurable environmental benefits and demonstrate public support for stronger sustainability policies. Earth Day Network announced that it reached one billion registered actions in 2012, ahead of the Rio+20 United Nations conference.

A common mix-up is “Mobilize the Earth,” which was the theme associated with Earth Day 2012, not the campaign’s name. “Billion Acts of Green” referred to the action-counting initiative itself, while the campaign later continued to highlight broader environmental commitments and projects.