The sensitivity of cereal crop productivity to a carbon dioxide-induced climatic change: A case study in the Mackenzie Basin, Canada

Current climate conditions impose limitations on agricultural opportunities in the Mackenzie River Basin. Anthropologically-induced changes to the composition of the Earth's atmosphere could affect these opportunities. A crop-weather model was used to evaluate wheat and barley potential under a range of future climate regimes at 15 sites in 3 ecoclimatic regions (ECR) located in the Basin. The altered climate regimes were based on an effective doubling of atmospheric CO{dollar}sb2{dollar} given the baseline weather set; a Composite climate scenario developed for the region, and, scenarios generated by the Geophysical Fluid Dynamics Laboratory (GFDL) and the Canadian Climate Centre (CCC) global circulation models (GCMs). The effects of altered climates were estimated for seeding dates, days to maturity, crop moisture stress, grain weight to canopy weight ratios, and crop yields.; Estimated seeding dates were earlier and the estimated days to maturity were reduced in all ECRs under all climatic change scenarios. The 2XCO{dollar}sb2{dollar} regime generated large increases in estimated yields at nearly all sites. Estimated yields tended to be lower under the other regimes when compared to estimated yields under baseline conditions, except at the sites located in the High Boreal ECR. In most cases, there was little change in the estimated grain to canopy ratio, and there was a decrease in estimated crop moisture stress. These results imply that the beneficial direct impacts of elevated levels of atmospheric CO{dollar}sb2{dollar} on estimated cereal yields could be offset by changes in the climatic conditions that may result from these higher levels of CO{dollar}sb2{dollar}. Estimated changes to the variables analyzed often varied greatly between the specified climatic change scenarios, but a pattern of regional variation was not generally apparent.