Climatic change and agricultural production in the Canadian Prairies

Implications of climatic change on agriculture in the Prairies are reviewed with special attention paid to the predictions of the Goddard Institute for Space Studies (GISS) general circulation model (GCM). The GISS GCM predicts an increase in growing season length of 48 days, advancing the growing season start by 19 days in the spring and extending it by 29 days in the fall, an increase in daily mean temperature of 1.3-2.3 degree C, an increase in precipitation by 30-40% and an increase in potential evapotranspiration of 40-60%, effectively making the area drier. Frequency of drought could be increased by a factor of 3-10. The overall result would be a shift of the climate in Nebraska 800 km to the south, north to Canada. It is suggested that spring wheat maturation time would be reduced 4-14 days, the present north-south pattern would be reversed, and maturity requirements throughout Saskatchewan would be more homogeneous. Taking into account a possible 15% increase in yields caused by enhanced carbon dioxide concentration, spring wheat production may still decrease 6-14%. Precipitation will have to increase substantially above projected levels in order to maintain productivity at current levels, a 20-25% increase in photosynthetic capacity will be needed to overcome projected temperature and moisture effects, yield and productivity decreases will be greater in northern agricultural areas, and yields and productivity throughout Saskatchewan will be more homogeneous. A shift to longer growing season varieties or the introduction of new crops will be required. Extensive shifts in crop zonation are likely. 26 refs