Ever Green.

Maybe it's cause to celebrate when a celebration outlives its usefulness. Back in 1970, there was lead in our paint, smog in our cities and poison in our pesticides; Ohio's Cuyahoga River was so polluted it caught fire the year before. So when Wisconsin Senator Gaylord Nelson called for a day of protest and teach-ins, 20 million people took part. In San Francisco, activists dumped oil in the reflecting pool at Standard Oil's headquarters; in Florida, college students put a Chevrolet on trial for poisoning the air, pronounced it guilty and sentenced it to death by sledgehammer. The Daughters of the American Revolution called it all "subversive."

This year half a billion people in 175 countries marked Earth Day in a global festival of political showmanship and corporate spin. President Bush planted an oak in New Orleans (249,999 more would bring the canopy back to pre-Katrina levels). In Indonesia, activists painted themselves green (above). Bolivia's socialist President Evo Morales told the U.N. that "if we want to save our planet Earth, we have a duty to put an end to the capitalist system." And capitalists polished their image to a green sheen: Macy's unveiled a new solar-power system in San Jose, Calif.; Chevron ran ads extolling the power of "human energy" to save the world.

Meanwhile, the rest of us wrestled with our choices: do we swear off meat, swap canvas for plastic, ditch the lawn, change the bulbs, wonder if it's too late? "I hope this movement is not a fad," one activist told a TIME reporter after the first Earth Day 38 years ago, "but the signs are not encouraging." On the one hand, less than three months later, President Nixon created the Environmental Protection Agency. The air and water got cleaner, DDT was banned, leaded gas phased out, recycling phased in. On the other hand, the world's population has nearly doubled, glaciers are melting, gas is within a drip of $4 a gallon, and there are food riots in countries where prices have soared owing to the diversion of grain to biofuels.

So what on earth is there to celebrate? Only this: 38 years after the fact, there's no need to stop us in our tracks and force the issue onto the agenda. In 2008, every day is Earth Day.