Mankind has to introduce sustainable development within the 21st century if basic life conditions are not to be put at risk. Above all, this demands eventually taking note of the limitations of non-renewable energy resources and of the limited capacity of local and global ecosystems to deal with disposal and emissions. For the resulting problems, we have to develop solutions. But sustainability is more than the protection of the natural environment. Justice, social stability, and adequate opportunities for education and employment for all people are of similar importance for our future. Both a transformation of energy policy in industrialized countries and a new policy for support of the less developed countries are necessary to prepare the way for a sustainable global community. Today we are far from such sustainable development. Global energy con­ sumption and the resulting emissions are still rising considerably and in­ creasingly endanger the ecological stability of the earth. Growing scarcity and rising prices of fossil fuels may lead to economic and political instability in many countries in the near future. In addition to this critical develop­ ment there exists an extreme divide in prosperity between industrialized and less developed countries, which is partly caused by an imbalance in access to sufficient and affordable energy, and which itself leads to conflicts and environmental damage.