ABSTRACT
This chapter examines the consequences of current world consumption and production systems for the various natural systems that sustain life on Earth. It includes a discussion of criteria that can be used to determine which of the changes inflicted on the life-sustaining system by humankind should be regarded as problematic and an overview of the main problems. Natural catastrophes may endanger the life-sustaining system but they are not considered environmental problems though their contribution to problematic situations can be enormous. A more or less constant flow of energy is indispensable to maintain the vital functions of the living species. Ecosystems can be characterised by the quantity of biomass that they contain and the energy that is consumed in the system. The lithosphere contains 99.99% of all carbon: there is far more carbon in the lithosphere than in fossil fuels.
