The greenhouse effect in WA
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Impacts of global climate change are difficult to predict at a sub-continental or regional level or for particular time scales. However, international global climate models suggest that as atmospheric greenhouse gas concentrations continue to rise, Western Australia will become warmer and rainfall patterns will change.
In the southwest of Western Australia, rainfall has already decreased and is projected to continue decreasing throughout this century. Future increases in temperature and potential evaporation are also anticipated.
| Climate variable
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2030
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2070
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Climate projections
versus predictions
A climate projection is based upon simulations by climate models, which include assumptions about future socioeconomic and technological developments that may or may not take place. They are therefore subject to uncertainty.
A climate prediction attempts to produce a most likely description or estimate of the actual evolution of the climate in the future.
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| Mean summer temperature (ºC) |
+0.5 to +2.1 |
+1.0 to +6.5 |
| Mean winter temperature (ºC) |
+0.5 to +2.0 |
+1.0 to +5.5 |
| Mean winter rainfall (%) |
-2 to -20 |
-5 to -60 |
| Potential winter evaporation (%) |
+0 to +10 |
+0 to +30 |
| Source: Indian Ocean Climate Initiative, 2005 |
| Note: These climate projections were done under a range of IPCC emissions scenarios and using nine international models that best reproduce Australian climatology. It should be noted that there is unavoidable uncertainty in the emission scenarios as it is impossible to predict human behaviour globally. |
These changes to the State's climate could directly affect agriculture, forestry, health, biodiversity, water resources, energy demand, tourism, fisheries and industry. The stress on Perth's water resources will only continue to grow, with further projected rainfall decreases.
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