Hydro-economic consequences of climate change in the upper Rio Grande

Social, economic, and environmental systems in arid regions are vulnerable to disruptions in water supplies that are likely to accompany future climate changes. With a particular focus on the Rio Grande in New Mexico, this paper uses a hydro-economic model to integrate plausible changes in population and climate over the coming 70 yr. Specifically, projections of regional population growth are combined with alternative climate scenarios in order to simulate changes in streamflows, water supplies, and water demands within a framework that economizes water use. The study uses 3 climate change scenarios across 2 distinct future time periods to model runoff, water supply, and water demand changes, and estimate the economic and water-use consequences. Specifically, temperature and precipitation scenarios were generated using results from 3 general circulation models (GCMs), namely, HadCM3 (Hadley Centre for Climate Prediction and Research Met Office), CSIRO (Commonwealth Scientific and Industrial Research Organization of Australia), and the GFDL0 (Geophysical Fluid Dynamics Laboratory of the National Oceanic and Atmospheric Administration), all of which were driven by the A1B emissions scenario from the Intergovernmental Panel on Climate Change's Special Report on Emissions Scenarios. The WATBAL hydrologic model and the Rio Grande hydro-economic model were used to model the hydrologic and economic consequences, respectively. Findings indicate that agricultural water users could be most affected by curtailed deliveries and higher water scarcity. Municipal water users are likely to face higher delivery costs as competition for scarce surface water supplies rises; however, groundwater supplies provide an effective buffer for many of the municipal systems and help ameliorate price spikes.