The mystery of summoning up words. Where are they in the mind, in the brain? They appear to be an agency from nowhere. They exist somewhere in our ground or in our air. They come from unknown darkness. From a place we normally don't think about.

I think most of our major challenges are not going to be in the physical field at all. I think they’re going to be in the field of human relations, of getting on with each other, of contributing. People accepting that they have to contribute something, their thoughts, their ideas, maybe even their money, towards producing a world society that is perhaps a little bit more honest and reasonable than it is now.

There are many battles. There’s so much that needs to be done. We need to protect the environment. Save this little planet. Not just this little piece of real estate we call America, but save the planet.

So a great deal has changed, but we in the Truth and Reconciliation Commission said, “Watch it. You can kiss reconciliation and forgiveness goodbye, unless the gap between the rich and the poor — the haves and the have-nots — is narrowed, and narrowed quickly and dramatically.” So yes, we face very, very considerable problems.

The advice that I would give is try to find something that you like. Try to devote your energies to being very good at it. Try to achieve excellence. Don’t necessarily have as a goal success or getting prizes or whatever, but just doing very good work. And work hard. Keep working at it. Be patient. Realize that you don’t always see the benefits of what you’re doing, short-term. But in the end, the activities that I do, for example, scientific research, can be extremely rewarding. It’s really a very fascinating career.

In terms of this issue of these industrial gases affecting the environment, at the beginning the road was not easy, because we were suggesting that society had to change, that industries had to do something different than they were doing at that time. And of course, initially we did not meet with a good reception to these ideas from industry. And even from the scientific community — even though our ideas were well received in the small group of specialists in what we were doing — it was not necessarily well received by the scientific community at large. So we really had to continue doing as good a science as we could, and at the same time trying to well communicate our conviction that it was something important, something that had to change in the way society was functioning.

proud of recognizing that as a scientist, it was not only important to do research and find new things. I also felt a responsibility to apply them for the benefit of society.

Sherry offered me a list of research options: the one project that intrigued me the most consisted of finding out the environmental fate of certain very inert industrial chemicals – the chlorofluorocarbons (CFCs) – which had been accumulating in the atmosphere and which at that time were thought to have no significant effects on the environment. This project offered me the opportunity to learn a new field – atmospheric chemistry – about which I knew very little; trying to solve a challenging problem appeared to be an excellent way to plunge into a new research area.

As I was starting my academic career, it was almost considered to be a negative signal to your career to get involved in politics ... But to me that was a sign you were doing something useful.

At first the research did not seem to be particularly interesting – I carried out a systematic search for processes that might destroy the CFCs in the lower atmosphere, but nothing appeared to affect them. We knew, however, that they would eventually drift to sufficiently high altitudes to be destroyed by solar radiation. The question was not only what destroys them, but more importantly, what the consequences are.