Climate models tend to predict an increasingly arid future for the Southwestern United States, in large part because of increased evaporation due to rising global temperatures. But current climate models do not handle precipitation well, and are not able to accurately model natural variability. This talk will leave the climate models, and present actual precipitation data across the Southwestern United States from 1860 to the present, focusing on the long term natural variability, which to date is much larger than any global warming related precipitation component. Multi-decadal variations of average precipitation of +/-20% around the long term mean are largely driven by Pacific Ocean sea surface temperature changes.
Presented by Bob Harper. He has a A.B. in Applied Mathematics from Harvard University (1965) & a PhD in Space Physics from Rice University (1972). His dissertation was on the dynamics of the Earth's Upper Atmosphere. Harper was also a geophysicist in the Petroleum Industry.
Light refreshments afterwards.