Glaciers in the tropical Andes have been retreating for the past several decades, leading to a temporary increase in dry season water supply downstream. Projected future glacier shrinkage, however, will lead to a long-term reduction in dry season river discharge from glacierized catchments. This glacier retreat is closely related to the observed increase in high-elevation, surface air temperature in the region. Future projections using a simple freezing level height- equilibrium-line altitude scaling approach suggest that glaciers in the inner tropics, such as Antizana in Ecuador, may be most vulnerable to future warming while glaciers in the more arid outer tropics, such as Zongo in Bolivia, may persist, albeit in a smaller size, throughout the 21st century regardless of emission scenario. Nonetheless many uncertainties persist, most notably problems with accurate snowfall measurements in the glacier accumulation zone, uncertainties in establishing accurate thickness measurements on glaciers, unknown future changes associated with local-scale circulation and cloud cover affecting glacier energy balance, the role of aerosols and in particular black carbon deposition on Andean glaciers, and the role of groundwater and aquifers interacting with glacier meltwater. The reduction in water supply for export-oriented agriculture, mining, hydropower production and human consumption are the most commonly discussed concerns associated with glacier retreat, but many other aspects including glacial hazards, tourism and recreation, and ecosystem integrity are also affected by glacier retreat. Social and political problems surrounding water allocation for subsistence farming have led to conflicts due to lack of adequate water governance. Local water management practices in many regions reflect cultural belief systems, perceptions and spiritual values and glacier retreat in some places is seen as a threat to these local livelihoods. Comprehensive adaptation strategies, if they are to be successful, therefore need to consider science, policy, culture and practice, and involve local populations. Planning needs to be based not only on future scenarios derived from physically-based numerical models, but must also consider societal needs, economic agendas, political conflicts, socioeconomic inequality and cultural values. This review elaborates on the need for adaptation as well as the challenges and constraints many adaptation projects are faced with, and lays out future directions where opportunities exist to develop successful, culturally acceptable and sustainable adaptation strategies.
Bibliographical noteFunding Information:
This study was produced under the umbrella of the Andean Climate Change Interamerican Observatory Network (ACCION, grant S-LMAQM-11-GR-086 to M. Vuille), funded by the Bureau of Western Hemisphere Affairs of the United States Department of State . M. Vuille also gratefully acknowledges support from the International Hydrologic program ( IHP ) of the United Nations Educational Scientific and Cultural Organization ( UNESCO ). M. Carey's work was supported in part by the US National Science Foundation under grant # 1253779 . C. Huggel and N. Salzmann were supported by the Swiss Agency for Development and Cooperation through the Glaciares + project in collaboration with CARE Peru, and C. Huggel by the project AguaFuturo supported by the Swiss National Science Foundation (project no. 205121L_166272 ). A. Rabatel, T. Condom and J.E. Sicart acknowledge the contribution of LabEx OSUG@2020 (grant ANR-10-LABX-56 ), the Laboratoire Mixte International GREAT-ICE funded by the French Institut de Recherche pour le Développement ( IRD ) in collaboration with the Escuela Politécnica Nacional del Ecuador, Universidad Mayor de San Andrés in La Paz, and the French Service National d'Observation GLACIOCLIM. W. Buytaert acknowledges funding of the UK Natural Environment Research Council (contract NE/K010239/1 ). We acknowledge the World Climate Research Programme's Working Group on Coupled Modeling, which is responsible for CMIP, and we thank the climate modeling groups (listed in Table 1 of this paper) for producing and making available their model output. For CMIP the U.S. Department of Energy's Program for Climate Model Diagnosis and Intercomparison provides coordinating support and led development of software infrastructure in partnership with the Global Organization for Earth System Science Portals. We are grateful to two anonymous reviewers, whose comments helped to substantially improve this manuscript.
© 2017 Elsevier B.V.
- Climate change
- Water resources