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Projected changes in our climate
In the southwest of WA, rainfall has already decreased and is projected to continue decreasing throughout this century. Future increases in temperature and potential evaporation are also anticipated; however, predicting impacts of global climate change at a regional and local level is difficult.
The Indian Ocean Climate Initiative (IOCI) research program has been studying the climate of WA's southwest since 1998. Projections under all scenarios and all models point to drier conditions across the southwest in the future.
The current global climate models all agree on the direction of change in winter (June to August) across the southwest with a mean reduction in southwest WA's winter rainfall of approximately 20 percent predicted (Figure 1). Results from IOCI research for southwest WA projects that relative to 1960-1990 (Bates et al, 2008):
- By 2030, rainfall will decrease by between 2 to 20 percent;
- By 2030, summer temperatures will increase by between 0.5 to 2.1 degrees C;
- By 2030, winter temperatures will increase by between 0.5 to 2.0 degrees C;
- By 2070, rainfall will decrease by between 5 to 60 percent;
- By 2070, summer temperatures will increase by between 1.0 to 6.5 degrees C; and
- By 2070, winter temperatures will increase by between 1.0 to 5.5 degrees C.
Figure 1. Projected precipitation changes for 2030 relative to 1960–1990 as determined by runs from nine international climate models forced by the full range of the SRES scenarios and the 550 ppm and 450 ppm stabilization scenarios (Bates et al, 2008)
Fact sheet: The future of WA's climate
IOCI Stage 3 is improving our knowledge of future rainfall patterns over south-west and north-west WA. Research into the predictability of rainfall and efforts to improve climate models will provide useful information for climate-dependent industries such as agriculture.
Update to October 2010
- See Update on IOCI Research: WA Rainfall - What the past can tell us and what the future may hold
