Using producers’ own production and financial data from the Narrandra region, modelling was initially undertaken to assess pasture and livestock production, and enterprise profitability for two prior periods (1970-1999 and 2000-2009) to ensure the models were performing correctly. Modelling was then performed looking ahead to 2030, using 4 different climate scenarios. A self-replacing merino flock and a prime lamb enterprise was initially examined.
The enterprise modelled was based on an annual grass and sub clover pasture.
Weather predictions & pasture production
Projected weather for the four 2030 scenarios and the impact on pasture production are shown below
- Compared to 1970-1999, over the period 2000-2009 rainfall was 23% lower, average maximum temperature was 3% higher and pasture production 30% lower
- For 2030:
- The temperature increases are consistent (+8%) but the rainfall forecast is variable ranging from a 2% to a 19% decrease and averaging an 8% reduction.
- This leads, on average, to a decrease in annual pasture production of 23% and to maintain minimum ground cover a decrease in DSE/ha,
- The drop in pasture production (and subsequently stocking rate)is severe compared to other sites. A range of local soil types have been tried with no major beneficial effect. At present this site would appear to be an outlier and more works needs to be done.
Livestock & Financial Impacts, and Adaptations
Using the modelled pasture production figures, the impacts on livestock production and farm profitability were then calculated. Such impacts were initially based on a “business as usual” case i.e. no adaptations (changes to farm management practices) were made.
Then, by discussing these predicted results with farmers, a series of possible adaptations were agreed to and modelled. These adaptations were assessed for their ability (either individually or in combination) to help reduce the impact of climate change on livestock production and farm profitability.
To see the ‘business as usual’ impacts, and then what adaptations were proposed by producers and modelled for the sheep enterprises at Cootamundra, please click on: