The most visible manifestation of climate change in the American Southwest is its effects on water resources. Since 1999, the region's water supplies and major rivers have been tested by burgeoning population growth and drought. Model projections suggest increasing drought severity and duration due to rising temperatures, increased evapotranspiration, and enhanced atmospheric circulation from the tropics (Hadley circulation).

The Arizona Water Institute, Arizona State University, and University of Arizona convened a “knowledge network” of local, state, tribal, and federal water resources managers and scientists to identify climate change adaptation and response strategies.