Effects of changes in climatic variability on agricultural production

ABSTRACT: Daily outputs of the CSIRO Conformal Cubic Atmospheric Model (C-CAM) for the periods of 1961–1990 and 2065–2094 were used in the present study to derive changes in mean climate and in climatic variability, which were used by the stochastic weather generator LARS-WG to generate climatic change scenarios for 3 sites in southeast Australia. Climatic scenarios were coupled with the Agricultural Production System sIMulator (APSIM)-Wheat/Canola models to identify the influence of changes in climatic variability on wheat and canola production at 3 sites (Condobolin, Nhill and Wagga Wagga). Changes in climatic variability had negative effects on average wheat and canola yields at Wagga Wagga and Condobolin, and, in most cases, on the coefficients of variation (CV) of wheat yield, while the CV of canola yield experienced both positive (50% of the cases) and negative (50% of the cases) effects. Changes in climatic variability had positive (50% of the cases) or no (50% of the cases) effect on the average harvest index (HI) of wheat, whereas they had negative (33% of cases) or no (67% of cases) effect on the average HI of canola. Negative effects of changed climatic variability on the CV of HI for both crops were found. Our results demonstrate that the effects of changes in climatic variability on crop production vary across locations and impact indicators. Changes in climatic variability therefore need to be taken into account in agricultural impact assessment.