Mountain regions occupy about one fifth of the Earth’s surface, they are home to approximately one tenth of the global population, and provide goods and services to about half of humanity (Messerli & Ives 1997; see Box 1). Accordingly, they received particular attention in "Agenda 21", a programme for sustainable development into the next century adopted by the United Nations Conference on Environment and Development (UNCED) in June 1992 in Rio de Janeiro. Chapter 13 of this document focuses on mountain regions, and states:
"Mountain environments are essential to the survival of the global ecosystem. Many of them are experiencing degradation in terms of accelerated soil erosion, landslides, and rapid loss of habitat and genetic diversity. Hence, proper management of mountain resources and socio-economic development of the people deserves immediate action."
Moreover, mountain regions often provide unique and sometimes the best opportunities to detect and analyse global change processes and phenomena:
1) Due to the often strong altitudinal gradients in mountain regions, meteorological, hydrological (including cryospheric), and ecological conditions (in particular vegetation and soils) change strongly over relatively short distances. Consequently, biodiversity tends to be high, and characteristic sequences of ecosystems and cryospheric systems are found along mountain slopes. The boundaries between these systems (e.g., ecotones, snowline, and glacier boundaries) may experience shifts due to environmental change and thus can be used as indicators; some of them can even be observed at the global scale by remote sensing.
2) Many mountain ranges, particularly their higher parts, are not affected by direct human activities. These areas include many national parks and other protected, "near-natural" environments, including biosphere reserves. They may serve as locations where the environmental impacts of climate change alone, including changes in atmospheric chemistry, can be studied directly.
3) Mountain regions are distributed all over the globe, from the Equator almost to the poles and from oceanic to highly continental climates. This global distribution allows us to perform comparative regional studies and to analyse the regional differentiation of environmental change processes in mountains as characterized above. Moreover, mountain regions typically offer a wide variety of ecosystems within a small geographical area, thus providing a small scale model for latitudinal changes.
The continued capacity of mountain ecosystems to provide the goods and services listed in Box 1 may be threatened by the increasingly global scope of human impact on the Earth. Global environmental change can be broadly classified into two categories: systemic vs. cumulative changes (cf. Turner et al. 1990). Systemic changes affect the environments at global scales (e.g., trace gas induced climate change). Cumulative changes are generated by processes that operate at a local scale but that are becoming globally pervasive (e.g., land cover/use change, air pollution, loss of biodiversity).
A third source of change in mountain environments is globalization, i.e. the growing global integration of social, political and economic relationships. Globalization as it affects mountain environments is reflected in (1) demographic changes, such as population growth, seasonal (including tourism) and permanent migration, and changing age/sex structures; (2) the incorporation of mountain economies into extra-regional economies; (3) the increasing influence of urban processes and perspectives, through urbanisation and new communications, including transport and various electronic media; (4) increases in consumption; and (5) changes in the location of decision-making and institutional arrangements, resulting from policy developments at all scales (Price et al. 1999).
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Box 1: Goods and Services Provided by Mountain Regions. Goods provided by mountain regions to those living in these regions as well as to populations in lowlands include:
Services provided by mountain ecosystems include:
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For all the reasons mentioned above, mountain regions are of particular significance for various aspects of global change research.
For the next few decades, globalization processes are likely to be at least as important as environmental changes as factors promoting change in mountain regions. At the same time, the cumulative and systemic environmental changes may significantly threaten the ability of mountain regions to provide the critical goods and services described above, both to mountain inhabitants and to supply the extra-regional demands of other communities. Therefore, in order to mitigate these threats, this integrated workplan describes a series of co-ordinated experimental, observational, and modelling studies, with the aims of detecting and articulating the consequences of global environmental change and informing policy processes at local to global scales (Figure 1).
