See the publication of Wilfried Haeberli (Geography Department, University of Zurich) and Rolf Weingartner (Institute of Geography, University of Bern)
Icy mountains with their surface ice in glaciers and subsurface ice in permafrost constitute important water towers relating to multiple human needs for water security. Vanishing of their ice as a consequence of global warming affects this function in a predominantly negative way. Key impacts are (1) the formation of new lakes with new options for use but also changing risk conditions related to decreasing stability of surrounding frozen peaks at local scales of source regions, (2) shifts in seasonality and higher inter-annual variability of runoff which may affect water supply at regional to continental scales including the surrounding lowlands, and (3) rising sea level at global scale. Long-term effects over decades, centuries and even millennia are involved, making serious impacts inevitable already now and irreversible for generations to come. Sustainable adaptation requires comprehensive systems analyses including dynamic socio-economic aspects.