This book contains the lectures of a meeting in December 1988, organized by the Association of German Engineers (VDI). The eleven contributions deal with the possible climatic changes caused by the increase in CO/sub 2/ of the atmosphere by the combustion of fossil fuel. A survey of the climatic fluctuations of the past is given and the principles of climate models are described. Other contributions deal with the influence of the cryosphere and the clouds on the climate and with the influence of aerosols on the radiation balance. The coupling of climate and biosphere and chemical reactors of trace gases in the atmosphere are also presented. Some important measures for the reduction of the increase of CO/sub 2/ by changes in the energy policy are discussed. (KW).