It's widely debated how exactly it started, but the roots of the modern environmental movement trace back to the 1960s. Early in the decade, Rachel Carson published her nonfiction work"Silent Spring" as a wake-up call to current and impending environmental concerns. Several years later, U.S. Sen. Gaylord Nelson (of Wisconsin), one of the government's first eco warriors, sought to harvest general awareness and turn it into a movement. He hit on the idea of an event, modeled after the anti-Vietnam war teach-ins of the day, to raise eco consciousness nationwide. The event that turned into the first"Earth Day" took place on April 22, 1970, and became the catalyst for a series of nature-based legislation and eventually the emergence of a mainstream environmental movement.

Back then, the issues were only broadly understood. There was some talk about extinctions of wildlife, scarce groundwater supplies and a niche-but-growing theory about something called climate change (Was the Earth, NEWSWEEK wondered in the 1970s, getting colder—or was it getting warmer?). Still, there was an emerging consensus that our planet's resources are not infinite, and if the exploitation of them remained unaddressed, bigger problems awaited. The takeaway for the 20 million people who participated that first Earth Day in 1970 was simple: we all live on the same rock; let's not foul our nest.

The first Earth Day was like the sounding of a bullhorn for the people to unite and get moving, which worked. But this year, 39 years later, the original intent has long eroded. The one-day demonstration that started a movement lost most of its luster decades ago. Yet we still have it—and that has alarming implications for our environmental progress. What was originally intended as the sounding of an alarm has been reproduced each year in the exact same way. The problem is, it's hard to be motivated by a screeching alarm when you've been hitting the snooze button for the last four decades. Even worse, maintaining an old solution to a problem that changes by the minute seems to compartmentalize a movement that, by now, should be much broader, more frequent and much more inclusive....