ERCIM News No.34 - July 1998

Sustainable Development and Integrated Assessment

by Achim Sydow, Helge Rosé and Waltraud Rufeger

A new research project about sustainable development was initiated this year by the Hermann von Helmholtz Association of German Research Centers. In the course of this project at GMD Institute for Computer Architecture and Software Technology interactive and integrated simulation tools for complex environment systems modelling will be developed. The integrated assessment approach to model complex systems on different levels of a hierarchy is introduced as a possible tool to address questions connected with the problem of sustainable development and global change.

With the third millennium approaching, the question of sustainable development is becoming an important concept to investigate different possible scenarios of our future: Is it possible to realise a development that meets the needs of the present and as well as those of future generations? This problem is closely related to the natural resilience and buffer capacity of the biosphere responding to the impact of human development, ie the question of global change.

The progress in human development is becoming increasingly dependent on the environment and may be restricted by its future deterioration. The problem of global change is complex in nature, represented by various interactions that operate on different spatial-temporal scales. Addressing these issues demands an integrative consideration of all relevant interactions between humans and the environment.

The reductionistic approach has failed in providing an adequate analysis of complex, large-scale global phenomena. A more promising route seems to be a more holistic, integrated approach, based on a systems-oriented analysis, which concentrates on the interactions and feedback mechanisms between the different subsystems.

Since the 1970s, there is a growing interest in an integrated approach to the problem of global change, called integrated assessment. In general, integrated assessment can be defined as an interdisciplinary process of combining, interpreting and communicating knowledge from diverse scientific disciplines in such a way that the whole cause-effect chain of a problem can be evaluated from a synoptic perspective with two characteristics: it should have added value compared to single disciplinary oriented assessment and it should provide useful information to decision-makers.

Integrated assessment is an iterative, continuing process, where on the one hand integrated insights from the scientific community are communicated to the decision-making community and on the other hand experiences and learning effects from decision-makers form the input for scientific assessment. In Europe, integrated assessment has its origins in the population-environment, ecological and acidification research. In North America the attention was mainly concentrated on the economic modelling. During the last years, integrated assessment models have increasingly focused on climate change and sustainable development.

The main questions under consideration today are: human health management and population growth, management of fossil fuels and renewable energy resources, safeguarding of food and fresh water and the stability of the biogeochemical cycles with respect to the human perturbations.

To model these complex systems, the Pressure-State-Impact-Response concept may be used as organizing principle for achieving a plausible division of the cause-effect chains into subsystems. The Pressure System represents social, economic and ecological driving forces underlying the pressure onto the human and environmental system.

The State System represents physical, chemical and biological changes in the state of the biosphere, as well as changes in human population and resources / capitals. The Impact System represents social, economic and ecological impacts as a result of human and/or natural disturbance. The Response System represents human intervention in response to ecological and societal impacts.

Modern integrated assessment approaches use a hierarchic structure to overcome the complexity problem of modelling. At the lower level of aggregation, economy-energy models operate in multi-year time steps with national or regional political boundaries. Their regional and distributed output data may be used in theme-specific models like RAINS (Regional Acidification Information and Simulation) or IMAGE (Integrated Model to Assess the Greenhouse Effect) at the next level of aggregation. Their results of characteristic simulations provide a guide line to setting up metamodels which establish the building blocks for integrated assessment models, eg the TARGETS system (Tool to Assess Regional and Global Environmental and health Targets for Sustainability) of the National Institute for Public Health and the Environment, The Netherlands/RIVM, at the highest level of aggregation.

This hierarchic system of models describes the problem at different levels of aggregation and integration. Therefore it provides a flexible framework of simulation tools which can help to answer the multifaceted questions regarding the understanding and managing of complex environmental systems. Based on this concept the GMD Institute for Computer Architecture and Software Technology will develop an interactive and distributed modelling system which is supposed to tackle questions connected with the problem of sustainable development.

Please contact:

Achim Sydow - GMD
Tel: +49 30 6392 1813
E-mail: sydow@first.gmd.de

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