"... We're not the center of the universe; we're way out in left field on a tiny dust mote, but it is our home and we need to take care of it."

"... We're not the center of the universe; we're way out in left field on a tiny dust mote, but it is our home and we need to take care of it."

— Apollo 8 Astronaut William Anders, commenting on his December 1968 "Earthrise" photo, the first image ever taken of Earth from the moon.

Rivers on fire, toxic chemicals and other environmental calamities awakened America's environmental consciousness in the 1960s. Back then, Earth Day was born out of the passion of peace activist John McConnell and U.S. Sen. Gaylord Nelson and first celebrated in San Francisco on March 21, 1970. Comments from the Apollo astronauts helped to inspire changing public perceptions. Today, Earth Day is celebrated in more than 175 countries around the globe.

At the time, growing awareness about an environmental crisis was sweeping the nation's campuses with an intensity that rivaled discontent over the Vietnam War. Mass demonstrations drew millions of concerned citizens and inspired bipartisan environmental laws such as the Endangered Species Act, the National Environmental Policy Act and the Clean Air and Clean Water acts. Today, we take pride in the recovery of the majestic bald eagle from near extinction, new wilderness areas that connect us to the great outdoors and cleaner air and drinking water. But in spite of these advances, we continue to play Russian roulette with the planet's ecosystems both globally and at home.

Consider these facts: Nearly every ecosystem on the planet is in disrepair; most of the world's fisheries are declining and coral reefs — nurseries of marine tropical life — are disappearing rapidly. Over half the planet's rainforests are gone (deforestation has averaged over 50,000 square miles each year); some 17,000 species are currently threatened with extinction and climate disruptions could trigger extinction of nearly a third of all the world's species within the lifetime of today's children. Many of these species give us medicines and foods. In our Pacific Northwest region, all but the last 20 percent of mature and old-growth forests have been logged.

So, as citizens of spaceship Earth, what can we do now to leave our children a livable planet?

Dozens of leading scientists from around the world, including myself, recently called on governments to enact a 12-step sustainability program by 2020. Among the provisions, we urged saving what remains of unroaded forests as they will increasingly be relied on for clean water, flood control and other amenities as climate disruptions wreak havoc on the planet's life-giving systems. Federal policies that protect national forest roadless areas, for instance, are fundamental to ensuring clean drinking water for millions of Americans.

We also called for tighter restrictions on logging old forests on public lands because, among their many benefits, they rid the air we breathe of global warming pollution. In Western Oregon, for instance, temperate rainforests store more carbon, acre for acre, in their dense vegetation, soils and massive tree trunks than even the world's tropical rainforests. When these rainforests are cut down, most of this carbon is released to the atmosphere as global warming pollution from decaying logging slash and transport and manufacture of wood products that rely on fossil fuels. On private timberlands, new financing is needed to pay private landowners for maintaining carbon stored in forests as a climate buffer.

The global species extinction and climate crisis of our times can be avoided, but only if we act on a grand scale to reduce global warming and bring our economy into compliance with what the environment can sustain. In addition to investing in renewable, clean energy technologies, Congress could redirect federal subsidies away from old-growth logging and into restoration activities that create jobs from thinning overgrown and flammable tree plantations and obliteration or repair of failing roads that choke salmon streams with sediments.

As we celebrate the 42nd Earth Day, this is an appropriate moment to remember the words of Apollo 8 astronaut Jim Lovell who — like fellow astronaut Andres — saw the distant Earth as "a grand oasis in the big vastness of space." As Lovell peered out his Apollo window he pondered that "the vast loneliness is awe-inspiring, and it makes you realize just what you have back there on Earth."

How long this oasis sustains us depends entirely on whether we constrain our rapacious consumption of the planet's finite ecosystems at a time of rapid population growth (we are now 7 billion people and counting). There is still time to achieve the vision of the first Earth Day leaders, but only if we are truly committed to embracing the old adage — "think global, act local!"

Dominick A. DellaSala is an award-winning book author of "Temperate and Boreal Rainforests of the World" (islandpress.org/dellasala) and chief scientist and president of Geos Institute (geosinstitute.org).