The rapid retreat of mountain glaciers is a notable consequence of global climate change. Glaciers help ensure the viability of downstream irrigation systems, hydroelectric facilities, and domestic water supplies during otherwise dry periods and therefore significant ice loss in the world's mountain areas is a water resource management issue of paramount concern. In Ecuador, 35% of Volcán Chimborazo's glacier cover has been lost in the past quarter century. Located in a semi-arid portion of the Ecuadorian Andes, Chimborazos glaciers serve as headwaters for four river systems, upon which more than 200,000 people directly rely for their water supply. At present, very little is known about the exact role these glaciers play in the hydrologic system of the mountain or the specific water usage patterns of the people living in the catchment area. This research project will address these uncertainties by answering the following questions: How fast are Chimborazo's glaciers melting, how much further will they melt under various climate change scenarios, how will additional glacier retreat impact overall water supply, and how socially and economically vulnerable are watershed stakeholders to these potential hydrologic changes? This project employs an integrative methodological approach that combines data analysis from hydrology, climatology and glaciology as well as integrative modeling, analysis of remotely-sensed data, and qualitative social science research techniques such as focus groups and key-informant interviews to answer the questions it has posed.
This research has the potential to assist the people of Chimborazo in identifying spatial and temporal patterns of potential water resource vulnerability and better position them to make informed water management decisions in the face of potentially disruptive changes to their hydrologic environment. The results of this study will therefore provide critical guidance to a range of internal (watershed stakeholders) and external (governmental agencies and non-governmental organizations) actors seeking to understand and mitigate local impacts resulting from global climate change. Furthermore, the methodology employed in this research will be of particular interest to others who seek to move past traditional disciplinary divisions in order to perform similar research.
The agricultural communities of the Ecuadorian Andes are highly dependent upon reliable water resources in order to pursue their livelihood activities. At Volcán Chimborazo, glacier retreat and shifting weather patterns are of great concern to those who live below the mountain and use its water. This project has sought to answer two important questions: How will the significant recession of Chimborazo’s glaciers alter the mountain’s hydrologic system and what are the potential consequences of these changes for stakeholders reliant upon Chimborazo for their water supply? The intellectual merit of this project is twofold: 1) provide actionable information that will aid local stakeholders in better managing their water resources; and 2) demonstrate that importance of integrative research that combines social and physical science methods and perspectives to address the challenges presented by climate change. The key findings of this research provide much illumination about the current climatic, hydrologic and glaciologic state of the area, and of challenges facing water users at present and in the decades ahead. A new, accurate glacier inventory for Chimborazo has been produced, which shows that glaciers have lost more than 20% of their surface area since 1986. Changing climatic conditions are apparent, though there is a curious discrepancy between the changes evident in the instrumental record and the perceptions of local residents. On the one hand, (admittedly sparse) instrumental data suggest that temperatures have increased ~0.25?C over the past quarter century while seasonal precipitation totals have generally remained unchanged. Conversely, there is strong agreement among residents that precipitation has decreased and become less predictable and that surface water sources are diminishing. Potential explanations for this discrepancy include the possibility that data collection standards are unreliable, that total precipitation is in fact similar but that rain events are of greater intensity but either shorter duration or lower frequency, or that other increasing water consumption rather than decreased precipitation is the cause of lower water supplies. Preliminary hydrological analysis indicates that that 10-20% of the water in the Rio Mocha system, which is heavily exploited by the Las Abras irrigation canal (the largest and most important system in the region), is sourced from glacier melt runoff. In addition, there is strong evidence that glacier meltwater is an important source of groundwater that manifests as spring discharge at the base of the mountain, a water source heavily exploited for both irrigation and domestic purposes. Because there is very little unallocated water left that originates from the slopes of Chimborazo, the gradual reduction of water flows that will occur if glaciers continue to shrink will contribute to increased water stress. Local residents are essentially unanimous in their opinion that agricultural productivity in the region is decreasing, and that increasingly unreliable water supplies are a primary reason for this. Whereas smallholder farming has been the dominant agricultural activity in this region for many centuries, the majority of households in the agrarian communities below Chimborazo must now earn a portion of their annual income from day labor or other activities off of their land. Furthermore, seasonal or permanent emigration to locations outside of the region has become increasingly common. There is a strong sense that this economic transition has had a deleterious effect on community cohesion due to land abandonment, a decreased male presence in communities during the work day, and shifting social networks that diminish the traditional role of neighborly cooperation as a central tenant of civil society. Contrary to common perception, it is irrigators rather than non-irrigators who are more vulnerable to future water stress. While non-irrigators have already begun adjusting their livelihood activities, irrigators remain reliant upon a water supply that is unable to meet demand. Nearly 70% of irrigators surveyed report that they do not always receive their full water allocation due to insufficient supply. Should rainfall patterns shift and glaciers continue their retreat as anticipated with climate change, many of these farmers will be faced with the decision to abandon their lands in search of more secure economic activities. In this rural region with few non-agricultural economic activities, that most certainly will mean yet more emigration. The new information resulting from this project should aid local water users their efforts to better manage their water and to improve the efficiency of their irrigation infrastructure. Illuminating the fact that water supply is increasingly unable to meet demand and that there has been a notable socioeconomic response to these conditions should aid governmental and non-governmental entities charged with allocating limited development resources in this region. Beyond Chimborazo, this research also serves as a useful case study for other researchers seeking to address the implications of climate change, showing the value of integrative research and the possibility that useful information can be obtained without the need for very large research teams.
