| Popis: |
Throughout the last few decades, scientists have generated a wealth of information from naturally occurring paleorecords of a wide spectrum of environmental and climate parameters which reflect evolution of Earth systems. A fundamental task of Global Change research is to disentangle human-induced climate change from the natural climatic variability of the past 200 years. A second fundamental task of Global Change research is to describe Earth system processes in sufficient detail to allow the development of a reliable global climatic model which will enable the calculation of scenarios of climatic and environmental change for given human forcings. To study the Earth system we rely on classical physical parameters, but new parameters reflecting the complex interplay of physical, chemical and biological processes also need to be analyzed in detail. An example of a parameter which integrates a broad spectrum of Earth system processes is the atmospheric CO2 concentration and its variability over the globe. Its fluctuations reflect changes in the physical and chemical steering of the ocean's biological pump and the exchange with the terrestrial biosphere and human activities such as CO2 production from fossil fuel use or human impact on the terrestrial biosphere. In the assessment of extreme events and their societal impacts the reference to similar events which happened in the past is essential. However, it is not the search for exact analogies of present events in the past, but of the underlying processes which will lead to a fundamental process-understanding of on-going and potential future extreme events. Hans Oeschger, chairman of PAGES – a core project of the International Geosphere-Biosphere Programme, gives his views on climate and environmental research and also the inherent dilemma of the scientists. |
