Ernst Ulrich von Weizsäcker is one of the pioneers of energy efficiency and eco-taxes in Germany. Founding President of the Wuppertal Institute (1991-2000), he was key in formulating the Energiewende (energy transition) debate in Germany. Previously he was a Professor of Biology and University President (at Kassel University) and from 1998-2005 a member of Parliament for the SPD (social democratic party) in the German Bundestag. He there headed the Commission of Inquiry into Globalization and was chairman of the Committee on the Environment.

You established the concept that prices must tell the ecological truth, so that dedicated consumers would not have to constantly struggle their way up a 'slippery slope'. In doing so, you have defined the need for a policy framework that would make sustainable consumption decisions become the norm. Where do you see signs that these ideas have been implemented in German politics?

In 1999, the Red-Green government introduced an ecological tax reform that has saved or created approximately 250,000 jobs and protects the environment. We have to pick up that thread once again.

What actions should politicians take to refine this legislative framework?

Ideally, there would be a political decision at EU level, and, if necessary, at the national level to raise the energy prices every year, matching the increase in energy efficiency in the previous year. With social tariffs for beneficiaries of the social welfare "Hartz IV" as well as revenue-neutrality for energy intensive industries. Such a decision would hardly cause any suffering, and it would trigger an avalanche of innovation and investment in energy efficiency, making the country richer and more competitive.

Which countries can provide a good example for the debate in Germany?

Japan, in the 1970s, under the shock of the oil crisis and a total dependence on energy imports, raised energy prices, making energy almost twice as expensive as in competing countries. The result was not the feared de-industrialization, but rather an explosion of technological innovation and a rapid strengthening of competitiveness.

The dynamics of economic development in emerging markets poses new challenges in the fight against the 'slippery slope'. Do you see any successful policy approaches there?

The emerging and developing countries can, in fact, much less afford to waste energy than the rich countries. China makes energy more expensive. India and South Africa are also on this path. They expect much from German efficiency technology.

Due to an increase in production and consumption, efficiency improvements have hardly produced the desired savings in energy and resource consumption so far. Where should we begin the fight against this "rebound effect"?

The rebound effect is the biggest problem. In most countries it is not even perceived or identified as a problem, but rather celebrated as growth. What we must achieve is a situation whereby efficiency is progressing faster than growth. Although this is currently technologically possible, it will not come about however, whilst energy is cheap.

Let's look at the demand side. How can the many successful civil society groups and initiatives form a critical mass, that is necessary to transform the market to fit sustainable production and consumption styles?

There are many encouraging initiatives for alternative lifestyles, such as the "Transition Towns" by Rob Hopkins. But these initiatives will remain a niche, unless the framework is changed, allowing sustainable consumption and production to become economically real, rational and lucrative.

Interview: Stefan Rostock