JB: What are the scientific issues bothering people today that don't worry you?

MADDOX: It's interesting that more than a quarter of a century has passed since the publication of The Limits to Growth, the Club of Rome document, which seemed to me to produce a far too simpleminded view of the global problem. The global problem is not the shortage of resources. It's true that we are using up petroleum at quite a rapid rate, two billion tons a year, and the amount of petroleum in the surface of the earth is not by any means infinite. But there's a natural balancing mechanism in those simple scenarios of shortage. The balancing mechanism is price. What we're pretty sure of is that we've now used up one dollar a barrel oil; it's all gone. There's some two dollar a barrel oil left in Saudi Arabia, but the Saudi Arabians are very careful about the degree to which they let their stuff be exploited, and that appears on the market at fifteen dollars a barrel like everybody else's oil. So price is really a regulator of scarcity.

Even when petroleum becomes so expensive that it's used only for the production of chemicals - some of the few chemicals that can be produced exclusively from petroleum - the world will not stop. There are plenty of other ways of generating energy which at present are more expensive than petroleum - like nuclear power, even solar power, in small quantities, like hydrogen, which can be made by electrolyzing water, and used as a fuel - so there are all kinds of ways. The future is going to be dependent upon on other sources of energy than the ones we at present use.

The argument that we're using scarce, irreplaceable sources of energy is an argument not worth its salt; not worth listening to seriously. We're using up cheap resources, and in due course we're going to have to use more expensive ones, which is an argument of course for wealth creation, economic growth. So my view of the Club of Rome's argument on the Limits of Growth is just that. It's an economic question, always has been, and it will be in the future and it will be dealt with in economic terms.

But the other environmental problems that seem to me to be much more important, are those concerning the safety of people's lives. After all, the avoidance of pollution is primarily a problem of how do you keep people healthy. That's what the end purpose is supposed to be, keeping people alive and healthy. The big threat there has been, and remains, infection, which we've talked about. It seems to me another is global warming. Global warming is the scenario that's supposed to happen when, because of the accumulation of carbon dioxide in the atmosphere, the temperature on the surface of the earth is increasing. I'm in a very odd position on this. I accept that global warming, because of carbon dioxide, is going to be a reality at some stage in the future. I disagree with the way in which the forecasts have been made by the organization called the Intergovernmental Panel on Climate Change, which is under the UN umbrella, although it's really a child of the United Nations Environmental Agency and the World Meteorological Organization.

These people have produced so far two assessments of the seriousness of global warming, and they predict that during the next century the temperature will increase by between two and three degrees centigrade - which doesn't sound much but actually would be a lot. This is the average temperature, and that would mean that in places like the southern Sahara it would become even more like a desert, and it might even mean that in some parts of the United States, like Texas, it would become a bit like the Sahara.

But the real problem is that all this is based on computer modeling, and while I'm fully enthusiastic about computer modeling as a way of understanding scientific problems, and comprehending large amounts of data, I think it's dangerous to rely on computer modeling when you are trying to make predictions about the real world. In fact the satellites that have been used to measure the temperature show that the temperature is increasing less rapidly than the computer models predict, by a factor of three. So I think that the scenario is less gloomy than the Intergovernmental Panel of Climate Change says.

On the other hand, it's going to happen sometime, and we have to do something about it. It raises the whole question about how do you get an equitable relationship between the rich and the poor countries. The rich countries have to acknowledge that they can't unilaterally deny developing countries the right to follow in the same kind of path as they themselves have followed in their own economic development. On the other hand, the poor countries have to accept that they can't let their demands on the global system increase as rapidly as their populations increase. They have to accept some kind of restraint on population as a tradeoff. That's going to be such a terribly difficult negotiation and it's very hard to see how it could be completed in the next century.