Pondering the Planet’s Future : Environment: The upcoming 20th anniversary of Earth Day prompts an assessment of what’s ahead for the world.

With visions of a 20th anniversary celebration of Earth Day approaching on April 22, environmentalists of every stripe converged by the hundreds on a Caltech lecture hall Wednesday for what was billed as a town meeting to ponder the future of the planet.

Speaker after speaker recounted both progress and backsliding on environmental fronts since the first Earth Day, a nationwide series of lectures and celebrations that were centered mainly on college campuses.

“I’m afraid what I’ve given you is a relatively quick and gloomy look at the atmosphere,” said UC Irvine scientist F. Sherwood Rowland after he showed a series of overhead projections that graphically detailed the deterioration of Earth’s protective ozone layer.

However, Rowland, once labeled a publicity seeker but now heralded as an environmental hero, explained that his discoveries about the ozone resulted from “a sequence of events that really had their origins” in the first Earth Day 20 years ago.

He said that he, like many other male scientists, became sensitive to environmental issues by following the lead of concerned women and children.

In 1974 Rowland discovered that substances used in aerosol sprays and as refrigerants damaged the ozone. He predicted that this damage would result in an increase in skin cancer and dramatic climatic changes.

To point out the delicate balance of the world environment, Rowland referred to the the Chernobyl nuclear power plant disaster of 1986. Just 14 days after the explosion, he said, the effects could be detected in the atmosphere in Irvine. “There are no regional problems when it comes to these gases,” he said.

Rowland and three other speakers addressed legal, scientific, social and political issues, setting the stage for local and national plans to develop a grass-roots consensus.

More than 135 people signed up to participate in small group discussions in the next two months. These will form the basis of a report that the environmentalists hope will influence legislators.

The gathering represented “a serious effort toward democratic action,” said Thurmon Couch, president of the Pasadena chapter of the United Nations Assn., which sponsored the event along with the western San Gabriel Valley Sierra Club.

Elizabeth Pomeroy, one of the program’s coordinators, said meetings such the one Wednesday “should have a kind of ripple effect through the 1990s.”