Before Al Gore became synonymous with global warming, Barry Commoner was warning the public about the delicate condition of planet Earth. Long associated with the Center for the Biology of Natural Systems at Queens College, Dr. Commoner has for decades been agitating to restore ecological balance to the biosphere, whether by outlawing nuclear testing or spreading the practice of recycling. Time magazine once nicknamed him ''the Paul Revere of the environmental movement.''

Dr. Commoner, who turned 90 on May 28, is enjoying something of a resurgence. The M.I.T. Press has just published a new biography, ''Barry Commoner and the Science of Survival,'' by Michael Egan. In August, he will be the subject of ''Science, Democracy and Environment,'' a symposium at the annual meeting of the American Sociological Association in New York. He is also writing a book on the subject that first brought him to public attention almost 40 years ago: whether DNA alone is responsible for an organism's traits.

Though he stepped down as director of the Center for the Biology of Natural Systems in 2000, Dr. Commoner still commutes to its headquarters from his home in Brooklyn Heights. At his house, with the Statue of Liberty in distant view, he recently reflected on his legacy.

Q. In 1970, around the time of the first Earth Day, you said, ''We have the time -- perhaps a generation -- in which to save the environment from the final effectsof the violence we have done to it.'' What's your assessment now?

A. We've really failed to do more than a few specific things. We don't use DDT on the farm anymore. We don't use lead in gasoline anymore. Environmental pollution is an incurable disease. It can only be prevented. And prevention can only take place at the point of production. If you insist on using DDT, the only thing you can do is stop. The rest has really been sort of forgotten about. Except that now, global warming has sort of consolidated the independent environmental hazards that many of us had been working on all of these years.

Q. So you don't think global warming is detracting from other concerns?


The Chinese like to say, ''Crisis means change.'' It means you can get things done. Unfortunately, I think that most of the ''greening'' that we see so much of now has failed to look back on arguments such as my own -- that action has to be taken on what's produced and how it's produced. That's unfortunate, but I'm an eternal optimist, and I think eventually people will come around.


A. No one in his right mind would deny that we're getting warmer. The question is, is this due to things that people have chosen? And I think the answer is that all of the things we have chosen to do include the release of materials like carbon dioxide, which affect the retention of heat by the planet.

You could argue that maybe this is a high point in a heating/cooling cycle. Well, we're adding to the high point. There's no question about it. So it seems to me the argument that there are natural ways in which the temperature fluctuates is a spurious one. If we accept that we're in a cycle, it's idiocy to increase the high point.

Q. There's been some second-guessing about using nuclear power instead of fossil fuels. Do you agree?

A. No. This is a good example of shortsighted environmentalism. It superficially makes sense to say, ''Here's a way of producing energy without carbon dioxide.'' But every activity that increases the amount of radioactivity to which we are exposed is idiotic. There has to be a life-and-death reason to do it. I mean, we haven't solved the problem of waste yet. We still have used fuel sitting all over the place. I think the fact that some people who have established a reputation as environmentalists have adopted this is appalling.

Q. There's also been some reconsideration of using DDT selectively against malaria, rather than as a mass-quantity pesticide. Have you rethought this?

A. Well, you know, I had something to do with the ban. I think there are situations in which you could use DDT surgically. I don't want to put anybody into a position of avoiding the use of something in a particular life-and-death situation. But there are many ways of solving the malaria problem, including reparations. Malarial regions ought to be given more money by wealthy countries. Until we get to the point where there is no other way to do it, I don't see any sense in it.

Q. Have you retreated from or reconsidered any aspects of your philosophy?

A. You mean have I made any mistakes? Well, I constantly think; I'm not used to rethinking. Let me think a minute. [Pause] The answer is no. I hate to say it. [Longer pause] What I have experienced over time is that environmental problems are easier to deal with in ways that don't go into their interconnections to the rest of what we are.

Take recycling. You can say this is something that people ought to do. And you forget that a lot of people live in cramped quarters. There's no way of putting extra recycling containers where they live. That problem of poverty will condition very much what you can accomplish. These people haven't the time to do it because they're living from day to day. I can think of situations in which, if I were doing it over again, I would have been more sensitive.

Q. How green a lifestyle do you lead?

A. Well, what suits me. I see no reason to have my shirts ironed. It's irrational. My wife and I try hard to do things that are sensible. I reject synthetics and plastics as a kind of religion. I tell people it's against my religion to wear plastic clothing. It's uncomfortable.

Q. Do you use mass transit?

A. I never use mass transit because to get from Brooklyn Heights to Queens College means taking the train into Manhattan and out again to Queens, then a bus. My time availability can't tolerate that. So I drove to work every day for a long time until a conspiracy between my wife and the director of the center convinced me that I should stop driving. And I now travel by taxi. I have never been an eco-freak. I think it's just a business of trying to weigh what your aims are, what your life is about. To me, it's more important to get my work done than to ride the subway.

Q. You ran for president as the candidate of the Citizens Party in 1980 and finished fifth. Have you been tempted again to run for office?

A. Often. Every time Bush does anything, I feel I should have won. You see, if I had won, we wouldn't have had Reagan. And if we hadn't had Reagan, the entire course of the country would have been different. I actually think it was a mistake to run a presidential campaign. It would have been much more sensible for me to run in the primaries and to make a good showing in a few states and make a point there.

The peak of the campaign happened in Albuquerque, where a local reporter said to me, ''Dr. Commoner, are you a serious candidate or are you just running on the issues?''

Photo: WARNING BELL: Barry Commoner is the subject of a biography and a science symposium. (Photograph by Liz O. Baylen for The New York Times)