The previous reports have outlined the current scientific knowledge of climate change and its impacts on tropical Andean glaciers and hydrology (Part I: The scientific basis) and the ongoing research and monitoring activities by the various institutions currently active in the region (Part II: Climate and Glacier Monitoring). It is clear that some practical measures to adapt and prepare for future changes in runoff behavior need to be implemented without delay (e.g.

This report provides the scientific basis regarding climate change and glaciers in the tropical Andes. It is meant to facilitate a discussion amongst policy makers and local stakeholders, who are in charge of implementing adaptation and mitigation strategies. Such measures, designed to alleviate the magnitude and impacts of climate change, can only be put in place with an accurate and detailed knowledge on how future climate change will affect glaciological and hydrological systems in the Andes.

This paper describes the challenges surrounding current and future water use in the tropical Andes by first reviewing the modern and future projected hydrological cycle and anticipated impacts on environmental services provided by glaciers and wetland vegetation. The discussion then elaborates on the current tensions and conflicts surrounding water use from a social and economic perspective and ends by focusing on the challenges ahead and looking at possible solutions for more sustainable and equitable future water use in the region.