Water for cities: The impact of climate change and demographic growth in the tropical Andes

[1] Globally, water resources for cities are under increasing stress. Two main stressors are climate change and population growth, but evaluating their relative impact is difficult, especially because of the complex topology of water supply. This is especially true in the tropical Andes, which is a region with strong climatic gradients and topographical limits to water resources. This paper presents an evaluation of both stressors on water resources in a geospatial framework to identify gradients in water availability that may lead to conflicts over water use. We focus on four major cities in, or receiving water from, the tropical Andes. A multimodel data set of 19 climate models is used as input for a regional water balance model. Per capita water availability is evaluated along topographic gradients for the present and for future scenarios of population growth and climate change. In all cases, the median projection of climate change suggests a relatively limited impact on water availability, but uncertainties are large. Despite these uncertainties, we find that the expected demographic changes are very likely to outpace the impact of climate change on water availability and should therefore be the priority for local policy making. However, distinctive geospatial patterns characterize the supply systems of the studied cities, highlighting the need to analyze the topology of water supply within an ecosystem services context. Our approach is flexible enough to be extended to other regions, stressors and water resources topologies.

[1]  C. Vera,et al.  Climate change scenarios for seasonal precipitation in South America from IPCC‐AR4 models , 2006 .

[2]  Marcos Villacís.  Ressources en eau glaciaire dans les Andes d'Equateur en relation avec les variations du climat : le cas du volcan Antizana , 2008 .

[3]  R. Célleri,et al.  Predicting climate change impacts on water resources in the tropical Andes: Effects of GCM uncertainty , 2009 .

[4]  R. Célleri,et al.  Hydrology and Earth System Sciences Uncertainties in Climate Change Projections and Regional Downscaling in the Tropical Andes: Implications for Water Resources Management , 2022 .

[5]  Wouter Buytaert,et al.  Human impact on the hydrology of the Andean páramos , 2006 .

[6]  Wouter Buytaert,et al.  Description and classification of nonallophanic Andosols in south Ecuadorian alpine grasslands (páramo) , 2006 .

[7]  D. Maraun,et al.  Precipitation downscaling under climate change: Recent developments to bridge the gap between dynamical models and the end user , 2010 .

[8]  N. Arnell.  Uncertainty in the relationship between climate forcing and hydrological response in UK catchments , 2011 .

[9]  J. Eischeid,et al.  Variability of Freezing Levels, Melting Season Indicators, and Snow Cover for Selected High-Elevation and Continental Regions in the Last 50 Years , 2003 .

[10]  O. Edenhofer,et al.  Intergovernmental Panel on Climate Change (IPCC) , 2013 .

[11]  C. Ringler,et al.  The nature and impact of climate change in the Challenge Program on Water and Food (CPWF) basins , 2011 .

[12]  L. Aragão,et al.  Exploring the likelihood and mechanism of a climate-change-induced dieback of the Amazon rainforest , 2009, Proceedings of the National Academy of Sciences.

[13]  Bernard Francou,et al.  Climate change and tropical Andean glaciers: Past, present and future , 2008 .

[14]  B. Bates,et al.  Climate change and water. , 2008 .

[15]  C. Vörösmarty,et al.  Global water resources: vulnerability from climate change and population growth. , 2000, Science.

[16]  D. Viviroli,et al.  Mountains of the World: Vulnerable Water Towers for the 21st Century , 2004, AMBIO: A Journal of the Human Environment.

[17]  E. Gerlach,et al.  Regulating Water Services for All in Developing Economies , 2010 .

[18]  M Falkenmark,et al.  Population and water resources: a delicate balance. , 1992, Population bulletin.

[19]  M. Vuille,et al.  Interannual Variability of Summertime Convective Cloudiness and Precipitation in the Central Andes Derived from ISCCP-B3 Data , 2004 .

[20]  A. Bebbington,et al.  Mining and social movements: struggles over Mining and social movements: struggles over livelihood and rural territorial development in the Andes , 2008 .

[21]  Keith Beven,et al.  I believe in climate change but how precautionary do we need to be in planning for the future? , 2011 .

[22]  M. Minvielle,et al.  Projecting rainfall changes over the South American Altiplano , 2011 .

[23]  L. S. Pereira,et al.  Crop evapotranspiration : guidelines for computing crop water requirements , 1998 .

[24]  O. Edenhofer,et al.  Mitigation from a cross-sectoral perspective , 2007 .

[25]  Jacqueline de Chazal,et al.  Climate change 2007 : impacts, adaptation and vulnerability : Working Group II contribution to the Fourth Assessment Report of the IPCC Intergovernmental Panel on Climate Change , 2014 .

[26]  M. Hulme,et al.  A high-resolution data set of surface climate over global land areas , 2002 .

[27]  Raymond S. Bradley,et al.  Interannual climate variability in the Central Andes and its relation to tropical Pacific and Atlantic forcing , 2000 .

[28]  Bodo Bookhagen,et al.  Orographic barriers, high‐resolution TRMM rainfall, and relief variations along the eastern Andes , 2008 .

[29]  M. Hulme,et al.  Assessing the robustness of adaptation decisions to climate change uncertainties: A case study on water resources management in the East of England , 2007 .

[30]  A. Liese,et al.  Explaining Varying Degrees of Openness in the Food and Agriculture Organization of the United Nations (FAO) , 2010 .

[31]  H. Fowler,et al.  Climate change and mountain water resources: overview and recommendations for research, management and policy , 2011 .

[32]  M. Beniston.  Climatic Change in Mountain Regions: A Review of Possible Impacts , 2003 .

[33]  Alistair Hunt,et al.  Climate change impacts and adaptation in cities: a review of the literature , 2011 .

[34]  J. Ronchail,et al.  Spatio‐temporal rainfall variability in the Amazon basin countries (Brazil, Peru, Bolivia, Colombia, and Ecuador) , 2009 .

[35]  R. Bradley,et al.  Climate Variability in the Andes of Ecuador and Its Relation to Tropical Pacific and Atlantic Sea Surface Temperature Anomalies , 2000 .

[36]  M. Rusticucci,et al.  Trends in Total and Extreme South American Rainfall in 1960–2000 and Links with Sea Surface Temperature , 2006 .

[37]  B. Bates,et al.  Climate change and water: technical paper of the intergovernmental panel on climate change , 2008 .

[38]  R. Bradley,et al.  20th Century Climate Change in the Tropical Andes: Observations and Model Results , 2003 .

[39]  Julien Lerat,et al.  Has land cover a significant impact on mean annual streamflow? An international assessment using 1508 catchments , 2008 .

[40]  Stephen H. Schneider,et al.  Simulating the effects of climate change on tropical montane cloud forests , 1999, Nature.

[41]  Petra Döll,et al.  Quantifying blue and green virtual water contents in global crop production as well as potential production losses without irrigation , 2010 .

[42]  P. McIntyre,et al.  Global threats to human water security and river biodiversity , 2010, Nature.

[43]  C. Vera,et al.  Climate change scenarios for seasonal precipitation in South America from IPCC-AR 4 models , 2006 .

[44]  H. Diaz,et al.  Threats to Water Supplies in the Tropical Andes , 2006, Science.

[45]  Richard Washington,et al.  Issues in the interpretation of climate model ensembles to inform decisions , 2007, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[46]  N. Arnell,et al.  Hydrology and Earth System Sciences Uncertainty in climate change impacts on basin-scale freshwater resources – preface to the special issue : the QUEST-GSI methodology and synthesis of results , 2011 .

[47]  L. Bruijnzeel,et al.  CLIMATIC CONDITIONS AND TROPICAL MONTANE FOREST PRODUCTIVITY: THE FOG HAS NOT LIFTED YET , 1998 .

[48]  D. R. Hardy,et al.  Recent changes in freezing level heights in the Tropics with implications for the deglacierization of high mountain regions , 2009 .

[49]  P. Döll,et al.  A global hydrological model for deriving water availability indicators: model tuning and validation , 2003 .

[50]  W. Buytaert,et al.  Potential impacts of climate change on the environmental services of humid tropical alpine regions , 2011 .

[51]  B. Mark,et al.  Tracing increasing tropical Andean glacier melt with stable isotopes in water. , 2007, Environmental science & technology.

[52]  Antoine Guisan,et al.  Predictive habitat distribution models in ecology , 2000 .

[53]  C. Gray,et al.  Environment, Land, and Rural Out-migration in the Southern Ecuadorian Andes , 2009 .

[54]  M. Meybeck,et al.  Mountains of the world, water towers for humanity: Typology, mapping, and global significance , 2007 .

[55]  Nigel W. Arnell,et al.  A comparative analysis of projected impacts of climate change on river runoff from global and catchment-scale hydrological models , 2010 .

[56]  G. Navarro,et al.  Mapa de ecosistemas de Los Andes del norte y Centrales. Bolivia, Colombia, Ecuador, Perú y Venezuela , 2009 .