TURN back the clock 20 years. Two thousand campuses across the United States are holding environmental conferences and students have forgotten about the war in Vietnam for one day to protest the nation's polluted water, air, and soil.
Two thousand community groups from coast to coast are promoting the need for greater grass-roots participation in cleaning up the country's environment.
Ten thousand schools are conducting special programs to impress on school-age children the need to fight pollution.
During the April 20, 1970, commemoration, the US staged a coast-to-coast mass protest. Car engines were symbolically buried, gas masks were donned, and ``America the Beautiful'' was sung - all to the delight of the nation's media. Some 22 US senators and governors from Massachusetts to Oregon participated in the nationwide activities.
Dubbed ``Earth Day,'' the peaceful environmental protest came on the heels of well-publicized ecological disasters in 1969, such as the Santa Barbara oil spill and the fire on Cleveland's Cuyahoga River.
``The first Earth Day helped prompt passage of the Clean Air Act and the Clean Water Act. It helped move the President and Congress to create the Environmental Protection Agency,'' says Denis Hayes, who helped launch Earth Day in 1970. ``But nearly 20 years later, the Earth remains at risk.''
Mr. Hayes, chairman of Earth Day 1990, says, ``Global warming, acid rain, ozone holes, rain forest destruction, and related problems threaten us now more than ever.''
Where the original Earth Day was largely a national event, Earth Day 1990 is a global effort. Anticipating more than 100 million participants, the promoters hope to launch a decade of international activity that stresses individual action as well as global pollution-cutting policies such as:
Banning chlorofluorocarbons that destroy the ozone layer.
Halting the export of toxic wastes and dangerous pesticides to the third world.
Beginning a 20-year transition from fossil fuels to renewable energy sources that won't contribute to global warming.
Reducing acid rain by 80 percent.
Creating a strong international agency with authority to protect the atmosphere and the oceans.
Global environment experts are heartened by the attention that Earth Day 1990 has generated.
``The good news is that more people are worried about the future of the planet than ever before,'' says Lester Brown, president of Worldwatch Institute. ``At the same time that this concern is rising, the cold war is ending. This presents the opportunity for redefining security and for seeing that the future threats are much less military and much more environmental.''
James Gustave Speth, president of World Resources Institute, says he sees similarities in the hype behind both the 1970 and 1990 Earth Day celebrations. But there have been changes in how environmental issues are addressed.
``The difference between [now and] 20 years ago is that then there was a rebirth and concern - but there was also a shift from backyard programs to federal programs as people saw that [environmental] problems could be dealt with at the national level. Now we see that problems can only be dealt with on the international and global level. This is matched by a corresponding shift back to state and local initiatives,'' Mr. Speth says.
``While I'm encouraged at the progress we've made in the past 20 years, it's hard to get a quantitative measure [on this progress],'' says Russell Train, chairman of the World Wildlife Fund and the Conservation Foundation. ``In the industrialized countries, with the exception of Eastern Europe and the Soviet Union, we've made significant strides in controlling sulphur dioxide, most of the water-pollution problems, and auto emissions.
``But having said that,'' Mr. Train adds, ``the level of economic activity has grown, the population has grown, the number of autos has grown - all tremendously in the past 20 years.'' He says depletion of the world's fisheries is of particular concern as world population rises and demand for food becomes ever greater.
Mr. Brown says the Worldwatch Institute's annual state of the earth surveys are not reassuring. ``All the things we were worried about in 1970, such as air and soil pollution, are far worse today than they were then,'' he says.
``If you were to start now without experience of the past 20 years, you'd say things are dreadful,'' says Brown. ``Having been around longer than a lot of people, I tend to see that a lot of progress has been made. But we have a hell of a long way to go.''