Climate Change in Queensland under Enhanced Greenhouse Conditions (Final Report)
A CSIRO report on research undertaken for Queensland Departments of State Devlopment, Main Roads, Health, Transport, Mines and Energy, Treasury, Public Works, Primary Industries and Natural Resources.
Kevin Walsh, Wenju Cai, Kevin Hennessy, Roger Jones, Kathy McInnes, Kim Nguyen, Cher Page and Peter Whetton
The CSIRO Division of Atmospheric Research was commissioned by the Queensland Government to investigate the climate's response to increasing concentrations of greenhouse gases in the atmosphere. Management of the project has been the responsibility of Natural Resource Sciences (NRSc) within NR&M, with funds provided by a range of State Agencies and Government owned corporations.
The report summarises the extent of potential changes in temperature and rainfall in Queensland as well as analysing potential impacts on water quality in Moreton Bay and water availability in the Burnett River.
The Queensland Government continues to engage the CSIRO Atmospheric Research group to undertake further climate change scenario development for the State. The current agreement focuses on improving projections of rainfall changes with some assessment of potential impacts in the Central Queensland region.
Projected climate changes for Queensland can be summarized as follows:
By 2030, annual mean temperatures are projected to increase by 0.3 to 2.0 degrees Celsius (oC) above 1990 values. Much larger ranges are projected for 2070, with increases from 0.8 to 6.0oC. For Brisbane, annual mean temperature may increase from 20oC to between 20.3 and 22oC in 2030 and to between 20.8 and 26oC by 2070.
In Brisbane, the number of summer days with temperatures over 35oC is projected to increase from its present average of 3 days to 3-6 days by 2030 and 4-35 days by 2070.
Annual rainfall over Queensland is projected to decline over most of the State, although projections of rainfall change are less certain than for temperature.
Soil moisture is expected to decrease over most of Queensland due to increased temperatures and declines in annual rainfall. This decrease is most pronounced in the far interior.
Maximum tropical cyclone wind speeds are likely to increase by 5 to 10%, by 2050. This will be accompanied by increases of 20 to 30% in peak tropical cyclone precipitation rates. However, little change is expected in the regions of tropical cyclone formation, and there is no evidence that tropical cyclones travel further south.
The ranges of projected temperature and rainfall quoted in the report reflect the consideration of possible future levels of global emissions of greenhouse gases and, to a lesser extent, uncertainties associated with modeling the Earth's climate system. If future global emissions continue to grow strongly, then temperatures are expected to be towards the upper end of the ranges quoted in the report. If there are big reductions in global emissions, then temperatures are expected to be at the lower end of the ranges quoted. Assessing future global emissions beyond 2030 becomes increasingly difficult, and hence wider temperature and rainfall ranges are quoted for 2070.
Nevertheless, while Queensland's climate is highly variable and will continue to remain variable, climate change will eventually result in patterns of temperature and variability not experienced since European settlement.
The changes in temperature, rainfall and soil moisture will have impacts on infrastructure, agriculture, the environment and health. Recent studies summarised in the CSIRO report have concluded the following:
Tropical forests are sensitive to climate change and large changes in the distribution of forest environments are expected even for relatively modest changes in temperature (0 to 1 degrees) and rainfall (-10% to +20%). Strongest effects were seen at the boundary between different types of forest, such as rainforest and open woodland.
By 2050, average electricity demand in Queensland is projected to rise 1-4% (assuming no technological improvement), with peak demand rising by 1.5-7%. This is a relatively small increase compared with the likely increase in demand due to non-climatic effects.
Increases in wheat yield may be possible in the short term, due to increased carbon dioxide concentrations in the atmosphere; however, the benefits will quickly be lost as soil moisture continues to decrease, and production will fall.
Modest increases in tree growth are likely in parts of the semi-arid tropics, but declines in growth rates are likely in the monsoon tropics of tropical north Queensland, due to the adverse effects of warming on tree growth.
There are some obvious implications for water resources of the predicted decrease in soil moisture, including reduced runoff in some locations.
