Abstract

This paper uses dynamically and statistically downscaled projections to assess potential changes in the climate of the St. Louis metropolitan area, USA. Two sets of downscaled projections are used. The North American Climate Change Assessment Program (NARCCAP) provides dynamically downscaled projections for the relatively high A2 emissions scenario. The United States Geological Survey (USGS) provides statistically downscaled projections for multiple emissions scenarios; for this analysis, the A2, and the somewhat lower B1 emissions scenarios were used. For both data sets, projections for the 1971-2000 period are compared with projections for the 2041-2070 time period to assess potential changes by mid-century. There is a consensus among the models that temperatures in the St. Louis region would be expected to rise in each season. There is also an agreement among most models that increased greenhouse gas (GHG) concentrations would be associated with increases in spring and winter precipitation. The biggest discrepancy between the downscaled projections regards summer precipitation, with NARCCAP projecting decreases in summer precipitation, and USGS projecting increases. There is also an agreement among most model runs that increases in heavy precipitation would be associated with rising GHG concentrations. Socio-economic implications include a rising risk of flooding in the St. Louis area, rising risk of heat stress, and increased energy use. Possible adaptation options include levee system repair, adoption of stormwater best management practices, energy conservation and a multi-faceted response to heat waves.