I think it's the most urgent problem in the world... the population growth. We are now 5.7 billion people in this world. Roger Ravelle once calculated that this planet could at best feed 40 billion people if our...

[Q] ... demands for food would be lowered, in general.

Yes, if our demands for food would be lowered... not to eat too much meat, but to... that's a detour of the energy, of the free energy... and also if all the area in the world could be made as productive as the corn harvest in Iowa which is the highest yield you can think of. Well, I think we'll never get close to this stage when we use every bit of our planet for that, but you see how close we are to the limits and if you take our countries in Europe and some places in the United States locally we are populated as densely as if we would extend that over the whole world it would come up to 40 billion.  And we don't see yet how to get it under control, it grows and grows and grows and this would mean we would produce catastrophes with it. I looked at the growth law, it's even not exponential, it's hyperbolical, like in a hypercycle. What does it mean hyperbolic? It means it's not only a multiplication rate that children make children make children make children but at the same time more children reach an age where they can have children, that means the hygenic conditions, hygene conditions are becoming better, the food becomes better, the medication becomes better... but so even the periods of doubling shrink and shrink, it's not only... exponential all comes out of a constant doubling period, here the doubling periods shrink and shrink... so this is our problem. If we talk about environmental problems yes there are, of course, too many people and here we have to do a lot. We will need energy because energy is the only thing we almost could have an unlimited supply of if we really tried to make everything available. All the materials they are limited, they have to be circulated and... so these are problems and the question is if we look at the growth of our world in the last 50 years, if we think of what was brought about by communication, by computers, by ... we are not able to extrapolate what would happen in the next 50 years, what would happen in the next 500 years or... or larger times. If we go back 1000 years that was the time of Charlemagne if you would have asked him, 'What would happen in 1000 years?' I don't think he could have told you anything of what happened in fact.