Vulnerability assessment of climate-induced water shortage in Phoenix

Abstract

Global warming has profound consequences for the climate of the American Southwest and its overallocated water supplies. This paper uses simulation modeling and the principles of decision making under uncertainty to translate climate information into tools for vulnerability assessment and urban climate adaptation. A dynamic simulation model, WaterSim, is used to explore future water-shortage conditions in Phoenix. Results indicate that policy action will be needed to attain water sustainability in 2030, even without reductions in river flows caused by climate change. Challenging but feasible changes in lifestyle and slower rates of population growth would allow the region to avoid shortage conditions and achieve groundwater sustainability under all but the most dire climate scenarios. Changes in lifestyle involve more native desert landscaping and fewer pools in addition to slower growth and higher urban densities. There is not a single most likely or optimal future for Phoenix. Urban climate adaptation involves using science-based models to anticipate water shortage and manage climate risk.water sustainability | climate change | decision making under uncertainty | simulation modeling

Modelling potential impacts of climate change on water and nitrate export from a mid-sized, semiarid watershed in the US Southwest

“…By forcing a physical process-based hydrological-biogeochemical model (i.e., SWAT, a process based hydrology and water quality model) with downscaled data from a GCM, we are able to assess likely local climate-change trends and understand details of impacts on hydrologic processes and nitrogen transformation and transport in arid watersheds. In the southwestern United States, model-predicted future dryness and challenges to regional sustainability under drought situations are well documented (Cayan et al 2010;Gober and Kirkwood 2010;MacDonald 2010;Garfin et al 2013). The study watershed provides a good (2011-2040), 2050s (2041-2070), and 2080s (2071-2100) in the Sycamore Creek watershed system to investigate hydrologic and biogeochemical changes in the absence of land-use change.…”

“…Water is the most precious natural resource in semi-arid central Arizona, where dwindling water supplies confront rapid urbanization (Gober and Kirkwood 2010;Karl et al 2009). Several studies suggest that global climate change will have negative impacts on water resources in this region, with projections of significant decreases in stream runoff (Barnett et al 2008).…”

“…Change in the hydrologic cycle represents an important aspect of global climate change that is difficult to predict and likely to vary strongly regionally. In arid and semi-arid regions, global climate change may affect future freshwater availability through changes in the timing of snowmelt and reduced river flows (Barnett et al 2008;Gober and Kirkwood 2010). The arid and semi-arid Southwest (USA) has seen significant warming (Karl et al 2009;MacDonald 2010), although changes in its hydrologic regimes remain difficult to detect against the characteristic high interannual variability of rainfall and streamflow.…”

“…In the American Southwest, predictions of a drier future combined with rapid urbanization point to a sharp increase in demand for water (Gober and Kirkwood 2010;Karl et al 2009). Central Arizona's Phoenix metropolitan area, for example, has consistently exhibited among the highest rates of population growth in the USA, yet for this urban growth to be sustainable, an adequate water supply must be assured in the future.…”

Roadmap for sustainable water resources in southwestern North America

“…1), and today the basin supports 50 million people, 92% of whom live in urban areas. Between 2000 and 2030, the population in this basin is expected to grow by another 23 million people (6).…”