Using producers’ own production and financial data from the Grenfell 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.
Three enterprises were examined – Merino x terminal; Self-replacing merino flock; and Yearling steers run on an annual grass and sub clover and grass/lucerne 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 20% lower, average maximum temperature was 4% higher and pasture production 29% lower.
- These figures are among the biggest impacts in the state for this period
- For 2030:
- The temperature increases are consistent (+9%) although the USA 1 model is exceptionally high
- Rainfall forecast is more variable ranging from a +2% to -13%, and averaging a 5% reduction.
- Rainfall is significantly less affected than during the dry 2000-2009 period
- On average, there is an 11% decrease in annual pasture production (although it ranges from +1% to -21%). The USA1 and German models show a considerable reduction while the USA2 and UK models show no change or a slight increase
- Autumn and spring rainfall are most affected
- Winters are likely to be warmer with fewer frosts and the number of days with a maximum temperature over 30 Celsius will increase
- Pasture growth rates will be higher in winter, lower in autumn and will decline faster in summer
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 prime lamb enterprise at Grenfell, please click on: