The Andean Glacier and Water Atlas

such as the location and distance from the glacier, as well as other sources of discharge. Many of the Andean rural highland areas are particularly vulnerable for water shortage, especially in the arid and semi-arid regions of the countries. For example, the Andean highlands of southern Peru and Bolivia are hotspots of water stress, because of the semi-arid climate and marked seasonality. With limited hydrological storage capacity of the small upland catchment flows, the glacier meltwater has acted as a buffer mechanism. The water stress is further exacerbated by the fact that these are typically rural communities at risk of poverty and with limited adaptation capacity (Heikkinen, 2017; Hunt & Watkiss, 2011; IPCC, 2007; Moench & Stapleton, 2007). The situation is also concerning in high altitude population centres and cities, especially the areas that have to cope with a long dry season, of five to six months. The tropical Andean region is particularly worth mentioning, as the mountainous areas are highly populated and encompass some major population centres, such as Cuzco in Peru and La Paz and El Alto in Bolivia. While larger cities have greater emphasis on water storage infrastructure but with high levels of water stress, glacial meltwater has acted as a buffer from year to year. For example, an estimate of the monthly maximum contribution of glacial melt water to available water supply during a normal year, found that glacier melt contributed to circa 5 per cent of available water supply in Quito (Ecuador), 61 per cent in La Paz (Bolivia) and 67 per cent in Huaraz (Peru), whereas the monthly maximum contribution during a drought year to available water supply would increase the dependency to circa 15 per cent in Quito (Ecuador), 85 per cent in La Paz (Bolivia) and 91 per cent in Huaraz (Peru) (Buytaert et al., 2017)

The potential human impact of the decrease of glacial meltwater is subject to high uncertainties, however the consequences will be unevenly distributed among countries and the communities of the Andes. The vulnerability to these changes depends on the degree of sensitivity to the threat and people’s adaptive capacity of the system. For example, the risks of water scarcity will not affect people evenly, but people with limited funds and lack of social safety nets are more likely to suffer the worst from the impacts (Montaña et al., 2016). In general, the Andean countries are characterised by their inherent vulnerability to the effects and impacts of climate change, based on a combination of manifold vulnerability aspects. These include widespread and extreme poverty concentrated mainly in rural areas, social inequality, the importance of agriculture in the economy, urbanisation in risk-prone areas, high incidence of hydrometeorological extreme events and weak institutions (Doornbos, 2009). It is also worth mentioning the cultural impact, as many Andean communities have had a strong connection to the glaciers through cultural beliefs, social values and perceptions. The disappearance of glaciers and the changes in the traditional natural landscape is seen to have a symbolic meaning, which can be associated with the local communities and the threats to their future livelihoods (Kaenzig, 2015; Vuille et al., 2018). The extent of glacial meltwater contributing to streamflow On a global level, it is estimated that 140 million people live in areas where glacier meltwater provides at least 25 per cent of river discharge, on a seasonal basis (Schaner et al., 2012). The contributions of glaciers to people depend on a number of factors,

55