Y. M. Svirezhev, W. von Bloh and H.-J. Schellnhuber
Environmental Modeling & Assessment 4(4), 287-294 (1999)
Potsdam Institute for Climate Impact Research (PIK),
Telegrafenberg, P.O. Box 60 12 03, 14412 Potsdam, Germany.
A novel approach to the problem of estimating climate impact on social systems
is suggested. This approach is based on a risk concept, where the notion of
critical events is introduced and the probability of such events is estimated.
The estimation considers both the inherent stochasticity of climatic processes
and the artificial stochasticity of climate predictions due to scientific
The method is worked out in some detail for the regional problem of crop
production and the risks associated with global climate change, and illustrated
by a case study (Kursk region of the FSU). In order to get local climatic
characteristics (weather) a so-called "statistical weather generator" is used.
One interesting finding is that the 3%-risk level remains constant up to
1.0 - 1.1°C rise of mean seasonal temperature, if the variance does
not change. On the other hand, the risk grows rapidly with increasing variance
(even if the mean temperature rises very slowly).
The risk approach allows to separate two problems: (i) assessment of
Global Change impact and (ii) decision making. The main task for the scientific
community is to provide the politicians with different options; the choice of
admissible (from the social point of view) critical events and the
corresponding risk levels is the business of decision makers.
Keywords: risk analysis, global change, agriculture
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