Farm Table says:
What is the problem?
Climate change is predicted to cause a significant reduction in the productivity of grasslands and the livestock industry across southern Australia.This study aims to use simulation models to assess a range of pasture management practices as adaptation options.
What did the research involve?
The simulation use GRAZPLAN models in order to simulate the above-ground net primary productivity and profitability of livestock systems during a reference period and under future projected climate.The livestock submodel included an equation for reductions in animal intakes on hot days . The soil moisture budget and infiltration were simulated based on the SWRRB model of Williams et al. (1985).
What were the key findings?
The average annual rainfall differed widely among the four GCM projections: GFDL-CM2.1 showed the largest decrease of annual rainfall across the study area (10%, 11%, and 24% in 2030, 2050, and 2070, respectively), whereas 0%, 1%, and 3% increases were projected by CCSM3 for 2030, 2050, and 2070. Annual mean temperature increased at similar rates under all examined GCMs; the mean projected temperature increase averaged across the study area and all GCMs was 1.08C, 1.58C, and 2.48C in 2030, 2050, and 2070. Average annual rainfall and temperature were predicted to vary idely among downscaled GCMs across southern Australia. Declines in annual rainfall relative to the historical period increased over time.
For the climate scenarios modelled here, it is likely that in 2030, the feed-base adaptations we have examined can return profitability of all beef cattle and steer enterprises and the majority of Merino ewe enterprises to that of the 1970–99 reference period.At 2050 and 2070, at a majority of locations, the most profitable feed-base management option can partly return profitability of enterprises to that of the reference period.