Potential climate change and its effects on barley yields in Canada

The rising trend of global atmospheric carbon dioxide is expected to induce a change in climate. Despite the uncertainty regarding the magnitude of climate change, assessments of its impacts on agricultural production are demanded by policy makers. Currently, crop yield simulation models form a useful and practical approach for making the required assessments. The EPIC model, which incorporates the effects of elevated CO2 levels upon crop growth, was run to estimate barley yields from daily historic (1965-1995) maximum- and minimum air temperatures and precipitation at nine climate stations across the agricultural region of Canada. Climate change data, representing a 2xCO2 scenario, were constructed by superimposing the output from the Canadian Global Coupled model, which incorporates the effects of aerosols (CGCM1+A1) upon the historic data in such a way that both the mean and the variability of the weather parameters changed. Local soils and crop management practices were used , with the latter changing under the 2xCO2 scenario. Growing season temperatures increased by approximately 0.5 to 2 0C, depending on whether or not planting dates were adapted to the climate change scenario; precipitation changes were highly variable from one station to the next. Barley yields did not change significantly at most stations, but the yield variability increased under the 2xCO2 scenario.