Discussion in a relaxed atmosphere: Dennis L. Meadows in his country home in Durham, New Hampshire, U.S. Meadows (born 1942) is one of the best-known voices to warn against the catastrophic consequences of excessive growth. He holds a Ph.D. from the renowned Massachusetts Institute of Technology (MIT), where for many years he taught systems dynamics. Meadows has been a tenured professor of management, engineering, and social sciences. His specialist subject is the computer modeling of complex cycles and the behavior of such simulated worlds when subject to stress. His publications include the eco best-seller "The Limits to Growth" (1972).

A call for uncompromising efficiency: 36 years on from the publication of "The Limits to Growth," a study based on computer models, the U.S. systems theorist Dennis L. Meadows takes stock. His conclusion is skeptical and sobering: "The growing consumption of resources has reduced our scope for achieving sustainable development."

Professor Meadows, the publication of "The Limits to Growth" on behalf of the Club of Rome caused quite a stir back in 1972. Since then, two updates have appeared, each proposing the same pessimistic conclusion: The human race is living way beyond its means, and the signs of impending crisis have become even clearer.

There's a crucial difference: Back in 1972, the human race was still having an impact that the planet could handle - i.e. there was a balance between the availability of resources and their sustainable use by the world's population. Today we're way beyond that point. And given that we haven't made any radical changes since then, we're now gradually seeing the initial consequences around us. Our inertia is reducing our options more and more.

One of the concepts you have introduced into the sustainability debate is that of "overshoot." Could you tell us what this means?

"Overshoot" describes excessive growth and the delayed reaction to it. A car driver sees a stop sign, but valuable time elapses before he or she starts to brake. And although the driver reacts, the car doesn't come to a halt until after the white line. This concept can be applied to any scenario, ranging from the home mortgage crisis in the U.S. to the collapse of an ecosystem.

Seemingly, the only way to change things internationally is to negotiate treaties in which richer countries ask poorer ones to renounce growth and prosperity. Can there really be a dialogue between the first and third worlds on those terms?

I think it's utopian to imagine that the rich countries are going to sacrifice anything for the rest of the planet. After all, they haven't done so for the last 500 years. The debate on CO2 emissions shows just how absurd the whole thing is. When we say that each state is going to reduce emissions by 10 percent, then that's obviously much less fair on developing and emerging economies than it is on the rich countries. In the Kyoto Treaty, the rich and the poor are treated in exactly the same way. That's a serious mistake. A much more sensible solution would have been to set a quota for each country.

How should the international community set about achieving compromises on climate change and establishing a more sustainable use of resources?

Kyoto was a good and important starting point. This kind of treaty is never perfect at the first go. It took four or five international contracts to prevent any further depletion of the ozone layer. If you just fold your arms and say, there are problems with this treaty and therefore I'm not going to sign it, then you'll never reach an agreement. The sad truth is that our climate is going to get worse for centuries to come - and that's even if we were to reduce CO2 emissions to pre-industrial levels. We can no longer eradicate this problem; we can only try to reduce its impact.

Nevertheless, can achieving a greater efficiency in our use of energy have an impact?

The Energy Watch Group in Germany has concluded that the high point of oil production - so-called peak oil - has now been reached and that the decline will be unexpectedly abrupt. Compared to today, the amount of oil available worldwide is set to halve by the year 2030. The chances are pretty dim that renewable energy and greater efficiency will be able to make up for this shortfall so quickly. And given that energy is such a key pillar of our standard of living, then obviously the latter is going to change dramatically!

What action do you suggest policymakers should take in order to prepare for this radical change?

If I were calling the shots in a country, I would concentrate on the transport sector. It's not only a major consumer of oil but also one of the areas where it's most difficult to replace oil with another source of energy. You could certainly adjust some technological levers here. The transport sector is crucially important for a country's labor market and therefore for its gross national product. Widespread electrification would be one sensible solution here - i.e. electric trains and the use of electric vehicles - along with regional power generation from alternative energy sources, such as wind and solar power.

Anyone who is serious about the arguments in "The Limits to Growth" can't help but think about less consumption or stagnating standards of living. That's far a less attractive proposition than the promise of unlimited growth.

Most people don't have a clue about what growth means as an abstract concept. What they really want are tangible things: a bigger house, a better car, a higher income. Up to now, people have assumed that continuing growth will bring more material possessions for everyone. But that's going to change drastically.

Has the human race now reached the point of no return, meaning that we can only go downhill from here - or do we still have a chance to do something about it?

That's a metaphor from the world of aviation: When an aircraft reaches the point of no return, it means that it no longer has enough fuel to fly back to its point of departure and can only land somewhere else. In that sense, we've always been past the point of no return, since we can never really return to a previous standard of living. In the past, however, we had considerably more attractive options and also more room to maneuver.

How can get we get people to give up their faith in growth?

Our species developed at a time when every day was a fight for survival and no one was able to plan for 40 or 50 years ahead. Over a period of a few hundred thousand years, our nervous system became adapted to this situation, with the result that I really doubt whether people are capable of dealing with these problems in a proactive way. That said, some things are changing. People's worries about the destruction of the environment in their own neighborhood is an important factor in making them act. And one of the biggest incentives to take action on a local level will be rising oil prices.

Are there any positive signs - new technologies or countries pursuing policies that might give you cause for hope?

There are, indeed: for example, the decision by the Spanish government from now on to invest more in the railroad net-work than in building new roads. The big question is whether these good examples will have a lasting impact. We don't necessarily need additional technology to tackle our problems. More than likely, it would be enough if we were to use the technology we already have as widely as possible.

Can innovative technology - such as increased efficiency in our use of energy or resources, or more economical engines and greater recycling - also provide a solution?

Enhanced technology can certainly help, but we need to be clear about the fact that it can't solve the fundamental problem! Whatever model you base your projections on here, there's no way we're going to be able to increase efficiency and introduce new technology fast enough to offset the drastic fall in the availability of fossil fuels. And I'm not just talking about oil here but also natural gas and coal.

Isn't any kind of action here doomed to failure on account of the demands of the market?

No, it really depends on how you phrase the question. This question has a psychological and a financial dimension, and to explain it I'm going to have to tell you a story. A good friend of mine manages a green investment fund with a portfolio of US$ 350 million. His stated mission is to finance a company with zero CO2 emissions. So I asked him what return his investors were expecting on their capital. His answer was "20 percent." Well you can forget that! Sustainability won't generate any double-digit returns, but it will generate long-term ones.

Until very recently, terms such as "sustainability" or "carbon footprint" were only of interest to the specialists. Why is that?

Lots of the world's top decision-makers have a big interest in maintaining the status quo. And that means globalization and free trade. Some experts are pushing the idea that we should approach the issue of climate change as an economic problem and try to solve it with the method of discounted cash flow. But that only makes sense if I have the option of buying a solution tomorrow for a problem I have today and I then find myself faced with a choice of the type: "Should I repair my car now or buy myself a new one instead?" In this case, all I need to know is: What are the costs or the benefits of waiting? With the destruction of the environment, however, you can't calculate like that. How am I supposed to buy myself out of the problems caused by global warming? What kind of value do I place on a species of animal or plant that is in the process of becoming extinct?

What can a company like Daimler do?

To my mind, the major task for Daimler is to concentrate on achieving long-term corporate success rather than short-term profits. In the past, modern companies tended to first set their profit targets and then develop the technology required to meet those goals. In the future, that's only going to work the other way round, i.e. you'll have to first develop the technology, and the earnings will derive from that. What companies like Daimler certainly can do is to use technology as a lever and start to think now about what the transport sector will look like in the future.