United Nations Environment Programme (UNEP)
Global  Environment Outlook-1 - The Web version

Chapter 4: Looking to the Future

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The General Setting

The present chapter contains quantitative analyses of the status of and trends in selected environment and development issues current and future, regional and global. For selected issues, it describes events likely to occur in the relatively short time-frame considered in this report if no policy reforms are implemented.

Computer modelling techniques were used for the analyses in an attempt to capture the many complex interactions between the environment and the socio-economic fabric of life, especially for analysing potential future developments. The preparation of the chapter required the integration of diverse sets of information from different sources and disciplines. The basic data used for this chapter were also used to prepare the projections in the Department for Policy Coordination and Sustainable Development Trends Report.

A few important considerations should be kept in mind when reading a modelling effort like the one presented here: the analysis is not intended to predict the future even though it may seem so because only one scenario has been analysed so far. Besides, the current generation of modelling tools, although much improved since the early 1970s, is still limited. For instance, social factors, institutional practices, and the rate and type of technological development remain critical uncertainties. Furthermore, the ability of models to reflect reality in all its facets will always be limited by the possibilities of measurement as well as by gaps in knowledge about the interactions of biochemical cycles and human and environmental systems. And finally, results are always open to different interpretation by different groups of people.

In this chapter, present and future socio-economic driving forces are analysed, the resulting future conditions of the atmosphere and land are analysed, and the potential impacts on natural habitats and human health are projected.

Most assumptions in this chapter about future developments have been formulated by a team led by the Stockholm Environment Institute (SEI). It is a conventional development scenario, i.e., it does not consider any major future policy reforms. Tables 4.1 and 4.2 list the data used (Klein Goldewijk and Battjes, 1995; Raskin et al.,1996). Of course, there are many other "possible" futures. Some work on this is briefly illustrated in Figure 4.1.

Data used for the integrated modelling efforts in this chapter were previously collected by countries and compiled into international databases by the United Nations and other international organizations such as the United Nations Department of Economic and Social Information and Policy Analysis, the Food and Agriculture Organization, the United Nations Development Programme, the World Bank, the World Meteorological Organization, and the World Resources Institute. Complex processing of such base data then usually takes place during modelling exercises to derive value-added data sets such as population density, air emissions, or land cover. Details on data used for this chapter are given in van Woerden et al.(1995), while UNEP/UNDPCSD (1996) elaborates further on the core data issue.

For information on the models and the assumptions used to derive the analysis, the reader is referred to a separate Technical Report prepared by the National Institute of Public Health and the Environment (RIVM) in the Netherlands. Some of the models used (IMAGE, RAINS, AIM, TARGETS) have been extensively peer-reviewed and are therefore not documented in this chapter. Others (models for water satisfaction at drainage basin level, biodiversity pressures) are still being developed, so brief explanations are included in the text.

GEO-1 concentrates on the world while at the same time taking into account regional differences. The six regions used in the model-based analysis roughly match the UNEP regional divisions used elsewhere in this report. (See Figure 4.2.) Considering the many differences within some of the regions, subdivisions should be considered for future GEO Reports.

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