Possible Climate-Change Impacts on Water Supply of Metropolitan Boston

Abstract

A study of the possible impacts of climate change due to the equivalent of doubling the atmospheric CO 2 on the water-supply system of metropolitan Boston showed serious decreases in reservoir-system safe yield due to the climate-change scenarios of some general circulation models (GCMs). Temperature increases alone and a longer growing season also resulted in severe impacts. Impacts may be mitigated if there are increases in vegetation canopy evapotranspiration resistance due to enriched CO 2 or in precipitation. The decreases in reservoir yield occur because there is less streamflow and downstream-flow maintenance requirements require more water be released. The scenarios of other GCMs result in an increase in safe yield; in those scenarios, evaporation and evapotranspiration increases are offset by large increases in precipitation. The contradictory results of the GCMs are not surprising and again indicate the present uncertainty in climate-change impacts.