Earth Day, 40 Years Later: How Far Have We Come?

April 22, 2010— -- On April 22, 1970, the very first Earth Day, more than 20 million people joined in demonstrations across the United States.

Colleges organized teach-ins to draw attention to the pressing environmental issues of air and water pollution. A part of New York City's Fifth Avenue was shut down to accommodate the marching crowds. Congress recessed so that members could join the days' activities.

Organizers said it was the largest national protest in U.S. history.

Today, Earth Day participants are more likely to carry reusable shopping bags than picket signs. They're more likely to pledge their commitment online than in a line outside city hall.

Forty years later, the tone may have changed, but Earth Day organizers say about 1 billion people worldwide are taking part in the international day of environmental awareness. Many will continue to green their shopping habits, homes, cars and more.

But some environmentalists who remember the first Earth Day -- and the political will that was so palpable then – say they wonder if those individual changes will be enough, considering the massive challenges facing the planet on this Earth Day.

In 1969, the Cuyahoga River in Ohio was so polluted it caught fire. An oil spill off Santa Barbara, California, killed thousands of birds and other marine wildlife. City skies across the country were darkened by smog.

The environmental movement, energized in 1970, helped not only to clean things up but to change the public consciousness.

"There have been advances on almost every front in terms of reduced pollution in our air and water, millions of acres of land protected and parks created, a wide range of new technologies introduced and environmental sensitivities adopted in virtually every walk of life," said Eric Goldstein, director of the Natural Resources Defense Council's New York Urban Program.

In the decade after the first Earth Day, the Environmental Protection Agency was created by executive order and Congress passed the Clean Air Act, the Clean Water Act, the Endangered Species act and other key pieces of environmental legislation.