The day is arbitrarily chosen, not like a date of assassination or birth, and much effort goes into drumming up activities around the celebration.
This year, Earth Day is 40 years old. Let's go back for a moment to the decade in which it was conceived.
Earth Day in Review
Rachel Carson published Silent Spring in 1962; her influential book on chemical pesticides described their toll on human and animal life and helped lead to a ban on DDT. In the latter part of the decade, lunar orbiters captured images of Earth, which NASA released to the public.
It is hard nowadays to describe how stunning those pictures were -- the first view of the planet from another celestial body. Our orb of a home looked so bravely small and alone. Vulnerable and elegant, a pale gem gleaming against the black velvet of space. The images -- of hope and possibility and triumph -- were imprinted on the nation's consciousness.
In 1969, there was a catastrophic oil spill off the coast of Santa Barbara, California; thousands of sea creatures perished in waves of suffocating black sludge. U.S. Senator Gaylord Nelson visited the terrible scene, and his outrage inspired the idea of a day that would push environmental issues onto the agenda, as one story goes.
In its 1969 coverage announcing the new holiday, The New York Times noted that "rising concern about the 'environmental crisis' is sweeping the nation's campuses with an intensity that may be on its way to eclipsing student discontent over the war in Vietnam."
And in 1970, the year Simon and Garfunkel sang about a "Bridge Over Troubled Water" and the Beatles offered "Let It Be," Earth Day was launched. It was an unqualified success, with millions of people around the country joining in marches and conferences.
Some say Earth Day marked the beginning of the modern environmental movement. In 1972, Supreme Court Justice William O. Douglas wrote a dissenting opinion in a landmark environmental-law case, Sierra Club v. Morton, arguing that nature -- rocks and trees and water and sky -- had rights: "The voice of the inanimate object ... should not be stilled."
Our World Today
Since that first Earth Day, millions more gallons of oil have spilled into our oceans. Energy companies have blasted open mountaintops to harvest glittering seams of coal. Glaciers have melted, Arctic sea ice has thinned, icebergs have calved, drifted, and disappeared. And since then, carbon emissions have literally skyrocketed. The decade of the '00s is likely to close as the warmest in the modern record. Through it all, we have faithfully celebrated Earth Day.
They move through their lives in a daze, hardly aware of the world around them. They walk over rich-smelling loam under a canopy of sky and clouds and trees filled with birdsong, but their heads are bent down to peer into tiny screens clutched in their fists. That their planet is suffering, dying even, is more than they can bear to think about.
Unexpectedly, the people are given the gift of one day to celebrate their kingdom. Dimly, they remember that they were once bequeathed an Eden. They wake and see what is wrong, and they see what is right. They look again at that first image of their planet, that deep blackness of space that engulfs it, and realize that's what they should have kept in mind all along. Not their imagined dominance over natural forces but the nothingness that surrounds them, and into which all will go if that jewel is not cherished.
Our planet is wondrous, whether you are seeing it whole, from the moon, or up close, settling slowly into a crouch at the edge of the shore, watching the snails drag their homes over the warm sand around you.
Breaking the Spell
How do we learn to fall in love with the Earth again? It requires a deliberate decision to reconnect. I take walks -- on the beach, by a stream, through a wood. I tend plants. I sit and ponder the bark on a London plane tree.
I turn to the poets who express the force of this world -- to Emily Dickinson, Stanley Kunitz, Mark Strand, or Mary Oliver, who writes in "Long Life": "It is one of the perils of our so-called civilized age that we do not yet acknowledge enough, or cherish enough, this connection between soul and landscape -- between our own best possibilities, and the view from our windows. We need the world as much as it needs us, and we need it in privacy, intimacy, and surety."
If we are to survive, if we are to hand our grandchildren the keys to the kingdom, gratitude for the earth must become habitual, even spiritual. We need a daily devotional of thanks to the planet for what we have been given, along with a determination to do the hard work necessary to clean up the mess we have made.
Changing a light bulb matters, but it is not enough. The deep work of changing our attitudes toward our home is what will keep us on course. The time has come to turn the observance of one day into a yearlong advent calendar of offerings, counting down to the rebirth of a healthy, clean, balanced, nurturing planet. It's time to take actions that will really make a difference.
Ask yourself whether Earth Day matters. It does, if you do.
On the 40th anniversary of Earth Day in America, here's a look at the highs and lows throughout the years.
April 22, 1970: Twenty million Americans participate in Earth Day, the first nationwide environmental demonstration.
December 2, 1970: The Environmental Protection Agency is created.
April 22, 1971: The "Keep America Beautiful" campaign launches the famous commercial with a crying Iron Eyes Cody.
August 12, 1971: "Unless someone like you cares a whole awful lot, nothing is going to get better. It's not." Dr. Seuss publishes "The Lorax."
August 7, 1978: President Jimmy Carter declares an emergency at Love Canal, New York, over toxic waste.
March 28, 1979: Meltdown at Three Mile Island nuclear reactor.
September 16, 1987: Twenty-four countries, including the U.S., sign the Montreal Protocol, agreeing to phase out ozone-depleting chemicals.
March 24, 1989: The Exxon Valdez spills nearly 11 million gallons of crude oil into Prince William Sound, Alaska.
April 22, 1990: With 140 nations participating, the 20th Earth Day embraces corporate sponsors, inspiring Time magazine to dub it a "commercial mugging."
June 3 to 14, 1992: The Earth Summit in Rio de Janeiro draws representatives from 172 governments.
December 10, 1997: Julia Butterfly Hill climbs up Luna, a 1,000-year-old redwood tree, to protest the logging of old-growth forests. After 738 days she finally climbs back down, saving the tree and the surrounding forest.
April 22, 2000: The Internet helps 5,000 environmental groups inspire people in 184 countries to participate in the 30th Earth Day, which calls for action on clean energy.
August 2000: The first Toyota Prius hybrid car is sold in this country.
February 16, 2005: The Kyoto Protocol, aimed at reducing greenhouse-gas emissions, goes into effect. It is ratified by 141 nations -- but not the U.S.
May 2005: San Francisco chef Jessica Prentice, along with three other Bay Area foodies, coins the term locavore.
July 3, 2005: Gaylord Nelson, founder of Earth Day, dies at age 89. "The reason Earth Day worked is that it organized itself," the former U.S. senator from Wisconsin had said. "The idea was out there, and everybody grabbed it."
October 12, 2007: Al Gore and the United Nations' Intergovernmental Panel on Climate Change win the Nobel Peace Prize.
December 2009: A year after the polar bear is listed as a threatened species by the U.S. Fish and Wildlife Service, the U.N. Climate Change Conference in Copenhagen yields no targets to curb emissions.
April 2010: Earth Day celebrates its 40th anniversary. How will you commemorate the occasion?
Text by Dominique Browning
Timeline by Katharine Mieszkowski