Climate change and mountain water resources: overview and recommendations for research, management and politics

Abstract

Mountains are essential sources of freshwater for our world, but their role in global water resources could well be significantly altered from anticipated climate change. How well do we understand these changes today, and what are implications for water resources management and for policy? <br><br> With these questions in mind, a dozen researchers – most of them with experience in collaborating with water managers – from around the world assembled for a workshop in Göschenen, Switzerland on 16–19 September 2009 by invitation of the Mountain Research Initiative (MRI). Their goal was to develop an up-to-date overview of mountain water resources and climate change and to identify pressing issues with relevance for science and society. <br><br> This special issue of Hydrology and Earth System Sciences assembles contributions providing insight into climate change and water resources for selected case-study mountain regions from around the world. The present introductory article is based on analysis of these regions and on the workshop discussions. We will give a brief overview of the subject (Sect. 1), introduce the case-study regions (Sect. 2) and examine the state of knowledge regarding the importance of water supply from mountain areas for water resources in the adjacent lowlands and anticipated climate change impacts (Sect. 3). From there, we will identify research and monitoring needs (Sect. 4), make recommendations for research, water resources management and policy (Sect. 5) and finally draw conclusions (Sect. 6)

The ability of a GCM-forced hydrological model to reproduce global discharge variability

“…Ensemble uncertainties (CV) are large for arid African regions, the arid southwestern USA and for the desert region of Australia where the CV of precipitation of the ensemble of GCMs is large as well (Johnson and Sharma, 2009). High CV values are also obtained for mountainous regions, like the Andes ridge and parts of Asia, where the low GCM resolutions are unable to capture the high spatial heterogeneity (Viviroli et al, 2010). CV values are higher, and regions with high CV values are more extended, for relative Q90 and Q10 than for Q.…”

Glacier recession and water resources in Peru’s Cordillera Blanca

“…This model generates synthetic hydrographs from the watershed area, the glacierized surfaces, and the annual rate of loss of ice area. The glacierized coverage of a watershed is a critical parameter that generates disparities among basins in hydrological response to glacial retreat (Birsan and others, 2005;Lambrecht and Mayer, 2009;Alford and Armstrong, 2010;Koboltschnig and Schoner, 2010;Viviroli and others, 2010). However, the percentage of glacier area alone is often insufficient to describe glacial influence on stream discharge for a given watershed.…”

Uncertainties in climate change projections and regional downscaling in the tropical Andes: implications for water resources management

“…Mountain regions provide important environmental services, such as water supply for adjacent, drier lowlands (Viviroli et al, 2010), but they are also particularly fragile to environmental change. Many of the meteorological, hydrological and biological processes in mountain areas are characterised by strong spatial gradients that can be easily perturbed.…”