Rock Glaciers, Water Security and Climate Change in the Bolivian Andes
Thesis or dissertation
University of Exeter
Water security in the Bolivian Andes is projected to decrease with population growth and climate change. As one of the poorest countries in the region, Bolivia is particularly vulnerable to such changes due to its limited capacity to adapt. Key gaps exist in our knowledge of the Andean cryosphere, including a lack of information on alternative mountain water sources, such as ‘rock glaciers’. The presence and hydrological importance of these cryospheric features is unknown for the Bolivian Andes. Yet, with current and projected [ice] glacier recession forecasted to negatively impact water availabilty, it is important to gather data and understanding on these cryospheric landforms. Consequently, this PhD has created the first rock glacier inventory for the Bolivian Andes, estimated rock glacier water stores, assessed their hydrological importance in comparison to glaciers and modelled the implications of projected rising temperatures on rock glacier activity and permafrost extent. This information has contributed to scientific knowledge about the Bolivian cryosphere and, more specifically, has increased knowledge of the frozen store of water in rock glaciers in the arid mountains of Bolivia where future water security issues are expected in response to climatic change. The rock glacier inventory for the Bolivian Andes was built through expert photomorphic mapping of freely available, high resolution satellite data (Google Earth), supported by a programme of field work during July - August 2011 and July - August 2012. A total of 94 rock glaciers were found to exist in the Bolivian Andes between 15° and 22° S, of which 54 were classified as active, estimated to contain between 0.05 and 0.14 km3 of water. At the national scale, research demonstrated that Bolivian rock glaciers were not as relatively important as hydrological stores when compared to estimations of glacier water equivalences. At the regional scale, three study regions were identified and analysed: Cordillera Real, Sajama and Western Cordillera. Along the Western Cordillera where glaciers are absent, the hydrological stores of the rock glaciers could be considered important. With current and projected glacier recession, it can be assumed that the relative importance of rock glaciers will increase in the Cordillera Real and Sajama. Climate modelling of the the 0 °C isotherm as a proxy for permafrost extent also highlighted this projected decrease. The projected impact of this warming on permafrost extent is modelled to be a loss of up to 95% by 2050 and 99% by 2080 from present day extent. These results were disseminated back to residents of La Paz through a conference held in the third field season (2014). This research is valued as important as continued climate change and population growth are projected to reduce water security in arid regions of the South American Andes. Due to its elevation and high levels of poverty Bolivia is vulnerable to climate change with limited ability to adapt. Specifically for the city of La Paz, its heavy dependence on the glaciers of mountains for potable water supply leaves it particularly vulnerable, especially during the dry season.
NERC CASE studentship with Oxfam and Agua Sustentable
PhD in Geography