Regional climate change projections for use in impacts and adaptation research in south-east Australia.

Aim - NARCliM (NSW/ACT Regional Climate Modelling project) is a regional climate modelling project designed to provide regional climate change data for use in impacts and adaptation research across sectors. Method - The climate models used were carefully chosen to satisfy the following criteria: - The chosen models perform adequately for the recent past compared to observations. - The chosen models do not exhibit the same strengths and weaknesses in their representation of the climate (i.e. they are independent). - The chosen models span the plausible future climate change space. Using these criteria, an ensemble of 12 high-resolution simulations was performed using three Regional Climate Models (RCMs) driven by four different Global Climate Models (GCMs). First a series of long hindcast simulations (60 years) driven by reanalysis boundary conditions were performed to evaluate the regional climate model performance. Subsequently, a set of three 20-year simulations driven by GCM boundary conditions were performed. The three simulations cover the periods 1990-2009, 2020-2039, 2060-2079. Results - The ensemble is shown to span the range of uncertainty in the future climate change and can be used to inform risk assessments. The regional climate changes projected within NARCliM are compared to those obtained from the driving GCMs. Results show that regional scale climate influences can alter the projected future changes in various locations across Australia. Conclusion - Climate change impacts or adaptation research that relies directly on Global Climate Model simulations may be using future climate changes that are not a good estimate for their area of interest.

FIGURE 18: FUTURE CHANGE IN MEAN TEMPERATURE AND PRECIPITATION FOR THREE DIFFERENT REGIONS: REGION 5 (CENTRAL-WEST NSW); REGION 7 (SOUTH COAST); REGION 10 (SOUTH-EAST COAST)