The challenge
Changes to the climate system have occurred and are likely to continue
The international scientific community accepts that increases in greenhouse gases due to human activity have been the dominant cause of observed global warming since the mid-20th century. Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system.
Australia's changing climate represents a significant challenge to individuals, communities, governments, businesses, industry and the environment. Australia has already experienced increases in average temperatures over the past 60 years, with more frequent hot weather, fewer cold days, shifting rainfall patterns and rising sea levels. More of the same is expected in the future.
Our response
The most comprehensive climate projections for Australia
We worked with the Australian Bureau of Meteorology to produce the most comprehensive set of climate change projections for Australia ever released.
The projections are presented for eight distinct regions of Australia, each of which will be affected differently by climate change.
The projections are based on data from up to 40 global climate models, developed by institutions around the world, that were driven by four greenhouse gas and aerosol emissions scenarios. Results have been prepared for 21 climate variables (both on the land and in the ocean) and for four 20-year time periods (centered on 2030, 2050, 2070 and 2090).
Our scientists use results from climate models that are based on established laws of physics. Confidence ratings for the projections are based on five lines of evidence:
- model reliability at simulating the past climate
- consistency between models regarding the projected magnitude and direction of change
- results from relevant downscaled projections
- evidence for plausible processes driving the simulated changes, and
- the level of consistency with trends in the observations.
The projections draw on the full breadth of available data and peer-reviewed literature to provide a robust assessment of the potential future climate.
The results
Observed changes will continue into the future
Research has shown that most of the changes observed over recent decades will continue into the future. Projections suggest that for Australia:
Time series for Australian average temperature for 1910-2090 as simulated in the Couple Model Intercomparison Project Phase 5 (CMIP5), relative to the 1950-2005 mean. The central line is the median value, and the shading is the 10th and 90th percentile range of 20-year running means (inner) and single year values (outer). The grey shading indicates the period of historical simulation while three future scenarios are shown with colour coded shading. RCP8.5 (Purple, high emissions), RCP4.5 (Blue, intermediate emissions) and RCP2.6 (green, low emissions). ACORN-SAT observations are shown in brown and a series from a typical global climate model is shown into the future in light purple.
- hot days will become more frequent and hotter (very high confidence)
- sea levels will rise (very high confidence)
- oceans will become more acidic (very high confidence)
- snow depths will decline (very high confidence)
- extreme rainfall events will become more intense (high confidence).
Seasonal-average rainfall changes will vary across Australia.
- In southern mainland Australia, winter and spring rainfall is projected to decrease (high confidence), but increases are projected for Tasmania in winter (medium confidence).
- In eastern Australia, there is high confidence that in the near future (2030) natural variability will predominate over trends caused by greenhouse gas emissions. This means that while the trend is skewing the natural variability towards winter decreases, it will be relatively minor compared to the natural seasonal and annual changes, so continuing to manage for large natural variability will still be appropriate. For late in the century (2090), there is medium confidence in a winter rainfall decrease.
- In northern Australia and northern inland areas, there is high confidence that in the near future (2030), natural variability will predominate over trends due to greenhouse gas emissions. There is low confidence in the direction of future rainfall change by late in the century (2090), but substantial changes to wet-season and annual rainfall cannot be ruled out.
The time in drought is projected to increase over southern Australia (high confidence).
There is high confidence in increasing potential evapotranspiration (atmospheric moisture demand).
There is high confidence in decreasing soil moisture from mid-century in the southern regions (particularly in winter and spring) driven by the projected decrease in rainfall and higher evaporative demand. There is medium confidence in decreasing soil moisture elsewhere in Australia where evaporative demand is projected to increase but the direction of rainfall change in uncertain.
Southern and eastern Australia are projected to experience harsher fire weather (high confidence).
Tropical cyclones may occur less often, but become more intense (medium confidence).
Projected changes will be superimposed on significant natural climate variability.
Using the results
The Climate Change in Australia website provides easy access to the projections information and data.
The website houses 14 interactive tools for exploring data; a data download facility; a technical report describing the data sources, methods, observed changes and projections; reports and brochures that summarise the results for eight regions of Australia; a brochure on Data Delivery; a brochure on projections for selected cities; a Climate Campus for learning more about climate science and using projections in impact assessments; an online training course; and other resources for decision makers and communicators.