Risk analysis of possible environmental change and future crop production in South Australia

Abstract

The potential impact of future environmental change (climate change plus pCO₂ change) on wheat production in Roseworthy, South Australia, was assessed in a view of risk by using the APSIM wheat model. Possible future environmental change scenarios for 2080 were generated from the output of 9 climate models including GCMs (General Circulation Models) and RCMs (Regional Climate Models), historical climate records (SILO) and IPCC (Intergovernmental Panel on Climate Change) SRES (Special Report on Emission Scenarios) for Roseworthy. Plant available water capacity for a typical soil in Roseworthy was derived from the state soils database (Maschmedt, pers comm.). The APSIM (Agricultural Production System Simulator) Wheat module was run for the historical climate record (baseline) and eighty possible environmental change scenarios. A wheat crop was simulated for each year of a 100-year period under each environmental scenario. A critical economic yield was derived from current input costs, grain prices, and standard return on investment (3%) and resulted in a critical yield for Roseworthy of 1,870 kg/ha. The conditional probability of not exceeding the critical yield increased from 27% (low level risk) of years under the historical baseline to 35~50% (medium level risk) of years under the most probable environmental change scenario. This result indicates that some solid adaptation strategies should be put forward to deal with the increased risk associated with Roseworthy wheat production.