Climate Change and Tropical Andean Glacier Recession: Evaluating Hydrologic Changes and Livelihood Vulnerability in the Cordillera Blanca, Peru

Abstract

Abstract Climate change is forcing dramatic glacier mass loss in the Cordillera Blanca, Peru, resulting in hydrologic transformations across the Rio Santa watershed and increasing human vulnerability. This article presents results from two years of transdisciplinary collaborative research evaluating the complex relationships between coupled environmental and social change in the region. First, hydrologic results suggest there has been an average increase of 1.6 (± 1.1) percent in the specific discharge of the more glacier-covered catchments (>20 percent glacier area) as a function of changes in stable isotopes of water (δ18O and δ2H) from 2004 to 2006. Second, there is a large (mean 60 percent) component of groundwater in dry season discharge based on results from the hydrochemical basin characterization method. Third, findings from extensive key interviews and seventy-two randomly sampled household interviews within communities located in two case study watersheds demonstrate that a large majority of households perceive that glacier recession is proceeding very rapidly and that climate change–related impacts are affecting human vulnerability across multiple shifting vectors including access to water resources, agro-pastoral production, and weather variability. El cambio climático está causando una dramática pérdida de masa en los glaciares de la Cordillera Blanca, Perú, generando transformaciones hidrológicas en toda la cuenca del Río Santa e incrementando la vulnerabilidad humana. Este artículo presenta los resultados de dos años de investigación colaborativa transdisciplinaria para evaluar las complejas relaciones entre los cambios ambientales y sociales en la región. Primero, los resultados hidrológicos sugieren que ha habido un incremento promedio del 1.6 (±1.1) por ciento en la descarga específica de los desagües con mayor cobertura de glaciares (>20 por ciento de área glaciada), como una función del cambio en isótopos estables del agua (δ18O and δ2H) entre 2004 y 2006. Segundo, hay un gran componente (media de 60 por ciento) de agua subterránea en el descargue de la estación seca basado en resultados del método de caracterización de la cuenca hidroquímica. Tercero, los descubrimientos derivados de detalladas entrevistas a informantes claves y setenta y dos entrevistas de muestra aleatoria administradas a hogares de comunidades pertenecientes a dos estudios de caso de cuencas, demuestran que la gran mayoría de la gente intuye que la recesión de los glaciares está avanzando rápidamente y que los impactos relacionados con cambio climático afectan la vulnerabilidad humana por medio de muchos vectores cambiantes, incluyendo el acceso a los recursos hídricos, producción agro-pastoral y variación meteorológica. Key Words: climate changeglacier recessionhydrologylivelihoodsvulnerability关键词: 气候变化冰川衰退水文生计脆弱性Palabras clave: cambio climáticorecesión de glaciareshidrologíamedios de vidavulnerabilidad Acknowledgments This research was funded by the National Science Foundation (NSF No. 0752175, BCS—Geography and Regional Science) and included a Research Experience for Undergraduates (REU) Supplement. Additional funding for the LIDAR flight came from the National Aeronautics and Space Administration (NASA No. NNX06AF11G), The National Geographic Society Committee for Research and Exploration, and the Ohio State University Climate, Water & Carbon Program, and the Faculty Senate of the University of California, Santa Cruz. We acknowledge the cooperative assistance of Peruvian colleagues Ing. Ricardo J. Gomez, Ing. Marco Zapata, and others at the Unidad de Glaciología y Recursos Hídricos in Huaraz, Peru, and the following interview research assistants: Carlos Torres Beraun, Oscar Lazo Ita, Erlinda Marilu Pacpac, Jesus Yovana Castillo, and Gladys Jimenez. We recognize REU undergraduates Laurel Hunt, Sarah Knox, Galen Licht, Sara Reid, Michael Shoenfelt, Patrick Burns, Alyssa Singer, and Shawn Stone for fieldwork assistance. We also thank Kyung In Huh for assisting with LIDAR data display. This is Byrd Polar Research Center contribution number 1396.