Climate change will impact on the Australian grazing industries both through policies to mitigate greenhouse gas emissions and through the physical impact of warmer temperatures, increased atmospheric CO2 concentrations and changed rainfall patterns on pasture and animal production. The effects of these changes are uncertain and likely to vary regionally, depending on the combination of biophysical and policy changes.
For producers to make informed decisions about mitigation and adaptation options, industry- and region-specific information is required, as the outcomes will be determined by multiple and complex interactions between climatic change and farm systems management.
Biophysical models are the only means that we currently have available to decipher these interactions and provide simulations of likely future outcomes at a regional scale.
This project was one component of the Climate Change Adaptation in the Southern Australian Livestock Industries program. It focused on conducting and coordinating modelling activities to address key industry questions on climate change impacts, adaptation and mitigation for the southern Australian grazing industries.
This project used biophysical models to examine what dairy, beef and sheep grazing systems might look like at a regional level under future climate scenarios. Adaptation and mitigation options were also modelled to determine their impact on productivity, greenhouse gas emissions and farm businesses.
The project builds on the development of a distributed modelling team from five states addressing the impacts of climate change on grazing systems,expanding this work to explore industry- and region-specific impacts and appropriate adaptation options.
The team found an historical trend towards greater frequency of short spring growing seasons, and that this would be compounded into the future, resulting in higher pasture growth rates in winter and early spring, but a contraction of the spring growing season and an earlier onset of the dry summer period. The impact of future climates on pasture production will depend on the extent of warming and drying — total annual pasture production is generally resilient to climate changes of +1°C with 10% less rainfall, but further changes are likely to reduce annual pasture growth.
A comparison of whole farm greenhouse gas emissions showed dairy farms produce the highest emissions per hectare, followed by beef, sheep and grains. In terms of emissions intensity, cow/calf farms emitted more greenhouse gases per unit of product than wool, followed by prime lamb, dairy, steers and finally grains.
The study highlighted a range of strategies available to lower the emissions intensity of production, however researchers emphasised that they must be profitable in their own right to be widely adopted.
Other outcomes from the project include more than 15 peer reviewed papers, 15 conference papers and two book chapters, as well as signifi cant new modelling capability and capacity.