Technical Report - Impacts of Climate Chnage on Water Resources
Matt Gibbs, Graham Green and Cameron Wood
Science, Monitoring and Information Division Department for Water, Government of South Australia
Climate Change projections for South Australia indicate that a hotter, drier future climate is generally expected. If these projections are realised, the resulting decrease in rainfall and increase in evapotranspiration will lead to a reduction in water resource availability for the state. General Circulation Models (GCMs) are the best tools available for simulating global and regional climate systems, and simulating the changes that may occur due to increases in greenhouse gas concentrations. Generally, these models provide reasonable representations of past trends over large spatial scales for a number of climate variables, such as temperature and air pressure.
However, GCM results are too coarse to be adopted directly in water resource impact models, and downscaling of the projections to the local weather station scale is required. A number of downscaling studies have been undertaken previously in South Australia (e.g. Charles et al. 2006 and Charles et al. 2009), however they are based on the projections from only one GCM, and do not consider changes to evapotranspiration, only rainfall. Hence, further downscaling of GCM projections is required to provide suitable inputs for the Department for Water Impacts of Climate Change on Water Resources (ICCWR) Project.