Hume Weir in the Murray-Darling Basin.

Planning for climate change in the Murray-Darling Basin

Regional climate change scenarios have been completed for the Murray-Darling Basin to help decision-makers plan for adapting to and reducing the risks of climate change.

• 16 March 2006 | Updated 14 October 2011

• What CSIRO has done
• Temperatures will rise
• Reducing greenhouse emissions will reduce warming

What CSIRO has done

New regional climate change scenarios have been completed for the Murray-Darling Basin.

The region produces much of Australia’s food and fibre and is highly dependent on irrigated agriculture. Changes in water availability as a result of climate change will have a significant impact on how water is managed in the region.

These scenarios have been welcomed by decision-makers and underpin policy development and planning for adapting to and reducing the risks of climate change.

Temperatures will rise

Projections, first published by CSIRO in 2001, showed that by 2070, temperatures could rise between 1 °C and 6.5 °C during spring and summer in the Basin.

Since then, CSIRO researchers Dr Ramasamy Suppiah and Mr Paul Durack have updated and refined the projections.

Dr Suppiah and Mr Durack analysed 19 global and regional climate model simulations, and tested these against observed patterns of sea level pressure, temperature and precipitation. After extensive trials, they selected the nine best-performing models to construct temperature and rainfall changes for the Basin, and seven models to look at future potential evaporation.

The projections are based on the Special Report on Emissions Scenarios, published by the Inter-governmental Panel for Climate Change.

The team considered three possible scenarios for the years 2030 and 2070:

• 'business as usual': no explicit efforts to reduce emissions of CO₂
• reduce and stabilise emissions at 550 parts per million (ppm) by the year 2150
• stabilise CO₂ emissions at 450 ppm by the year 2100.

In the first scenario, 'business as usual', inland regions show warming in spring and summer of between 0.5 °C and 2.0 °C by the year 2030, and warming between 0.8 °C and 6.5 °C by 2070.

Rainfall predictions are highly variable and could decrease by as much as 60 per cent or increase by 40 per cent by 2070 in the Basin.  The changes more likely in the more northerly areas, which will be hotter, especially in spring. The southern and coastal parts of the Basin show less warming and a decreased shift in rainfall.

Rainfall projections for winter and spring are dominated by decreases. There are some projected rainfall increases in parts of the Basin, though these are mainly during periods of relatively low rainfall.

Evaporation will vary from 0 (no change) to 15 per cent in 2030 and 0 and 45 per cent in 2070. 

Reducing greenhouse emissions will reduce warming

These updated projections also confirm that policies which have the effect of reducing greenhouse emissions can have a measurable effect on regional global warming.

If we reduce CO₂ to 550 ppm (the second scenario), then warming will not be so marked, at least in the shorter term. The projection is for warming between 1 °C and 4 °C by 2070.

For the third scenario, 450 ppm, the projection is for warming between about 0.8 °C and 3.3 °C.

The range of rainfall decrease and evaporation increase are similarly less dramatic under scenarios of stabilised CO₂ concentrations.

The research was conducted as part of the Water for a Healthy Country Flagship’s Climate Change program. The findings will provide predictive capability to other research programs as we attempt to understand water variability in the Murray-Darling Basin.

View the projected temperature changes for the Murray Darling Basin by 2030 and 2070 for Figure 1. Units are in °C.

View the projected percentage changes in rainfall for the Murray Darling Basin by 2030 and 2070 for Figure 2.

View the projected percentage changes point potential evaporation for the Murray Darling Basin by 2030 and 2070 for Figure 3.

Read more about the Water for a Healthy Country Flagship’s Achievements.