A Modeling Perspective on Drought in Southwest North America

The IPCC AR5/CMIP5 global climate models robustly project a drying of southwest North America (SWNA) in the current century. However, it is far from easy to identify these trends in the century or so of observational data, likely due to the natural variability that impacts the region. An examination of the last millennium of drought history across the region and model analysis indicate that the near-term future hydroclimate of SWNA on the decadal timescale will depend on a mix of radiatively-forced change and evolving natural variability which could amplify or oppose the forced change at varying times and create bumps on the road to a drier climate.