The Andean Glacier and Water Atlas

The impact on future water availability Climate change projections highlight that Andean glaciers will continue to retreat, with smaller, low-lying glaciers expected to disappear in the near future. The overall impact on water resources may be limited to those areas closer to the glaciers. However, the impact on the seasonality of the streamflow in rivers fed by glaciers will be significant and reduce the buffer that glacial melt provides in the driest periods, even at large distances from the glaciated areas. These changes may be reinforced by the direct impacts of climate change on streamflow magnitude and variability. For example, one modelling study of the city of La Paz, Bolivia, highlights that in the case of a complete disappearance of glaciers and no changes in precipitation, the total water production for La Paz city will decrease by 12 per cent at an annual scale and by 24 per cent during the dry season (Soruco et al., 2015). Besides the impact of glacial retreat on water resources and the risk of glacial lake outburst floods (GLOFs), there are a number of other hazards related to climate change that pose risks to mountain and downstream societies. High-emission scenarios for the Andes project a significant amount of warming of between 2 to 5° celcius warming by the end of the century. Precipitation patterns, although difficult to predict, are likely to change in the future, with more precipitation projected by 2100 along the coastal regions of Colombia and Ecuador and in

some places along the eastern Andes, south of the equator, and decreases projected in the southern (tropical) Andes, including the Altiplano regions by 2100, leading to increased drought. Increases in extreme weather events, such as heavy rainfall, as well as an increase in extremely hot years, are also projected to increase, which in turn can contribute to floods, inundations, landslides and wildfires and direct impacts on food systems and human health. All of these will increase the vulnerability of the communities that live in or depend on the affected areas. Risk reduction and adaptation efforts also need to address these hazards. The decreasing amount of glacial meltwater, coupled with other climate change predictions, population growth, urbanisations trends, the growing importance of export-oriented large- scale agriculture, mining, energy and electricity – all point to increasing needs and competition for water resources in the Andean countries (Drenkhan et al., 2015). Results from several studies (such as Carey et al., 2017; Rasmussen, 2016; Buytaert & Bièvre, 2012) highlight that demographic changes in the Andean countries – for example population growth – are likely to be more important for future water scenarios and adaptation strategies than reduced water resources as a result of climate change. This also emphasises the need for adaptation strategies to water stress and scarcity, irrespective of glacial melting trends and future precipitation scenarios (Vuille et al., 2018).

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