more variation in seasonal weather patterns in high moun- tain ranges. Given current patterns and predictions, a likely scenario in the long run is that the monsoon becomes more variable, and that the water flow in the dry season is further reduced, in some cases to critical levels, due to disappearing glaciers (Jianchu et al., 2009).

Because the impact of glacier melt on river regimes is so vari- able between regions, it is vitally important to model hydrolo- gical impacts of climate change on a catchment-by-catchment basis. This task presents considerable challenges due to the great number and diversity of glaciers in high mountain catch- ments, complexity of the terrain and local microclimates, and lack of data on many components of the hydrological system. Until such studies are conducted, however, any predictions about the impacts of climate change remain speculative.

Regional differences present challenges

Mountain regions are diverse and complex ecological and so- cio-cultural systems. The world’s high mountain ranges and glaciers are suffering the impacts of a global phenomenon, but the way these consequences are dealt with will need to vary considerably with the local context. Mountains regions are and will be among the most impacted regions in the world, but current policies and actions aimed at alleviating impacts of climate change do not adequately benefit moun- tain regions.Furthermore, the diversity and heterogeneity of mountain ecosystems mean that adaptation and mitigation strategies must be tailored to specific natural- and livelihood conditions in order to be effective. The span between adapta- tion and mitigation should be thought of as a continuum. A particular strategy for storing water or food may work well in a particular setting, but have little or no relevance in another context. However, while recognizing the challenges related to regional differences in mountain settings, these areas also require global solidarity and concerted regional cooperation. Adaptation is in many cases about making micro-level chang- es within national responsibilities, but the large mountain regions also need regional, and even transboundary actions. Many watersheds and river systems in high mountain areas flow across more than one country. The established national and bilateral perspectives on water management will not suf-

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fice for dealing with future challenges. In a likely future of in- creased water scarcity in the dry season and enhanced hazards in the rainy season the pressure to find improved means to deal with too much water and too little water will increase dramatically.

This can only be addressed through integrated water resources management across broader scales.

Water stress impacts food security

In the future, many regions will undoubtedly experience water scarcity (UNEP 2010). Firstly, population growth is increasing the demand for water, and while 20 to 30% of current global water consumption is by households and in- dustry, rising populations will also increase the agricultural production demand for water. Secondly, the higher demand