Impacts of climate variability and climate change on prairie wheat yield.

摘要

This thesis focuses on the impacts of climate variability and climate change on the agricultural sector and regional economy of the Prairie Provinces. Three experiments, (historical analysis, climate variability simulations and climate change simulations) have been done to achieve this goal. Spring wheat yield of the region is chosen for analyses in this work as it dominates the regional output. The results indicate that spring wheat yield is highly dependent on water availability during the growing seasons. Dry pre-growing seasons give a better yield due to coincident warmer winters with longer growing season, and coincident higher summer precipitation. The influence of hot growing seasons on spring wheat yield varies, shifting from adverse to beneficial from south to north. The impact of the ENSO events on spring wheat yield is not statistically significant. Warming of the Prairies and elevated carbon dioxide concentration with no change or 25% higher than normal in annual precipitation give higher simulated yields, while the impact from high precipitation variability alone is negative on the yield. Warming Prairies with lower than normal precipitation reduces yields, except Manitoba which still shows a high yield due to an extending growing season. A warming climate favours to the northern Prairies more. The beneficial effect from elevated carbon dioxide concentration diminishes as carbon dioxide concentration increases. No significant difference is shown in simulated spring wheat under different scenarios, which indicates that spring wheat yield in the Prairies has a high level of climate resilience. Economic impact of climate change and climate variability on spring wheat is demonstrated, by the high correlation between regional GDP and spring wheat yield, further research on this issue is required.