3. Climate Change Effects on Ecosystem Services in the United States – Issues of National and Global Security

Climate change is one possible external driver of ecosystem services. In the tropical Pacific, short-term climate change is influenced by oceanic Kelvin waves that induce remote temperatures to rise (El Niño event) or decrease (La Niña event). This teleconnection is not globally uniform; in the United States (U.S.) drought conditions induced by El Niño commonly appear in the northern latitudes, whereas drought induced by La Niña occurs in the southern latitudes. Should natural or anthropogenic climate forcing influence the frequency or intensity of drought, there is a potential for catastrophic events to occur placing our national and global security at risk. Because climate forcing interacts with ecosystems characterized by nonlinear and multivariate processes over local-to-global and immediate-to-long-term scales, their assessment and prediction are challenging. This study demonstrates the efficacy of an alternative modeling paradigm based on using a self-organizing map to examine and predict the role that climatic change has on water-resource related ecosystem services. Examples include: (1) hindcasting 2,000 years of temperature and precipitation across states in the south-central and southwestern U.S.; (2) forecasting climate-induced groundwater recharge variability across subbasins in mid-western U.S.; and, (3) forecasting climate-change effects on post-fire hydrology and geomorphology in the western U.S.