Abstract
According to experts, a global warming resulting from the anthropogenic increase in the concentration of greenhouse gases in the atmosphere becomes more and more likely. These opinions are based on highly developed climate simulation models. However, as a result of the complexity of the system ocean - atmosphere - biosphere, there is still a great amount of uncertainty as to the regional extent of global warming.
Undoubtedly, in an interrelated world with an exponentially growing population, global climate changes mean a serious threat to man's foundations of life. Even within the frame of natural variability of the system, these changes can take place within very short time. This is confirmed by the results of ice core drillings on Greenland and stresses the importance of the issue of impact science.
Local and regional extents of global changes in climate cannot be safely predicted, but international scientists agree that the most severe effects will have to be expected in semi-natural and managed systems, which to a high degree are based on the present climate. As a result of these considerations, the scientific advisory committee of the Federal Government of Germany on global environmental change recommends the investigation and analysis of those systems (regions, sectors and social structures) in its annual report 1993, which, as a result of their sensitivity, seem to be especially endangered.
In Germany, especially in Northern Germany, the summer of 1992 and the spring of 1993 with extremely hot and dry weather, offered an ideal possibility of study the effects of a plausible climate change in a "natural laboratory". Scientists of various disciplines seized the opportunity and analysed the reactions of natural systems, and those which are influenced by man, towards this "climate anomaly". This was done in the interdisciplinary research project "Extreme Summer of 1992 in Northern Germany".
Coordinated by the Potsdam Institute for Climate Impact Research (PIK) and the Institute for Chemistry and Biology of the Marine Environment (ICBM) at Carl-von-Ossietzky-University in Oldenburg, quantifiable physical effects, socio-economic consequences and individual-psychological perceptions of the summer of 1992 were analysed. The summaries of the research work presented here comprise the most important results of all different parts of the project. Moreover, in "PIK Reports" the complete final report, consisting of two volumes and a German summary, have been published.
Within a narrow time frame, the following research topics had to be addressed:
• meteorological analysis
• complete recording of primary (and secondary) effects, if possible
• individual and social perception
• investigation of political, administrative, and personal reactions
• evaluation of models and forecasts
• integration to a common point of view
• identification of research deficits.
With regard to these goals a number of relevant and sometimes surprising details were found. Moreover, important experiences were made with regard to necessary interdisciplinary cooperation in research on regional effects of global change. It became very clear where further research is needed, which models and concepts of models have to be corrected and for which sectors models for a regional climate change scenario have to be developed. Moreover, it was realized that on the one hand the related effects weather - perception - reflection - reaction are correlated in different ways and react in a very sensitive way on distributions and that on the other hand the social system "Federal Republic of Germany" undoubtedly is flexible enough to cope with such irritations without a change of its internal structure, provided these irritations are results from singular events.
