The Andean Glacier and Water Atlas

Introduction

Mountains are often referred to as the water towers of the world, given their role in providing water to populations around the globe. This could not be truer than in the Andean region, where mountains play a crucial part in providing water to over 75 million people within the region, and a further 20 million people downstream. Some of this water is provided through rainfall. At higher elevations the glaciers have long provided a steady stream of meltwater when it is most needed, during the dry season. Yet the Andes is not, and has not been, immune to climate change. Several archaeologic studies have linked climate stress to the cultural behaviour of civilisations in the Andes (Binford et al., 1997; Dillehay & Kolata, 2004; Tung et al., 2016). The collapse of the Tiwanaka civilisation for example, coincided with rapid and significant climate change; drier conditions had affected the hydrological and ecological characteristics of the land the people used for agriculture (Binford et al., 1997). This mountainous region is once again entering a period of unprecedented change. Glaciers in the Andes are some of the fastest retreating in the world. In some areas, many glaciers have disappeared, while in other areas a steady decline will continue for decades to come.

With fast retreating glaciers, there is a paradox. Over the past few decades, many communities living beneath them may have enjoyed a period of relatively more abundant water, as the glaciers have released their meltwater. The evidence now shows most glaciers have reached their peak water output or will reach it within the coming decades. The signals are clear. They point to an urgency to better understand the environmental changes to come and to implement suitable adaptation responses. This atlas has been designed to provide a comprehensive overview of the status of glaciers across the Andes region and possible adaptation options. It is intended for policy makers in the region, as well as the general public. The start of the atlas focuses on introducing the region both in geographical, historical and socio-economic terms. Then, it describes the climate and specifically examines past and projected trends in temperature, and precipitation. The section entitled “Shrinking Ice” provides more detailed insights into glacial trends in each Andean country and projected trends. The “Accelerated Glacier Melt” section examines the impact on communities and various sectors of glacial melt and glacial outburst floods. A non-exhaustive overview of adaptation options is then provided and includes a series of best practise cases. The atlas concludes with a series of recommendations, particularly targeted at policy makers.

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