https://hdl.handle.net/10388/16539

Climate change has the potential to alter growing seasons worldwide. This study evaluates how agroclimatic indices and hotspots for compound events related to cool-season crops in Western Canada may change under the RCP8.5 scenario, using high-resolution climate data. The study employed a convection-permitting Weather Research and Forecasting model simulation for the current climate (CTL, 2000–2015) and future climate under the high-end emission scenario based on a pseudo-global-warming (PGW) approach. The multivariate quantile mapping method was applied to CTL and PGW to bias-correct the simulations to the GEM-CaPA dataset. An evaluation of the CTL simulation of daily temperatures and precipitation during the growing season against the gridded observation shows good agreement in Western Canada. The CTL captured the spatial pattern of agroclimatic indices and the hotspots of compound events, especially in the major croplands. Rising temperatures will result in substantial increases in growing degree-days (GDD) and reductions in frost days, favoring the expansion of crop fields and pushing temperatures to optimal conditions of growth for cool-season crops. However, plant heat stress and Temperature Humidity Index will substantially increase in the southern prairies, Okanagan, and the Fraser Valley offsetting the positive effects caused by the reduction in frost days and increases in GDD. Extended dry days coupled with substantial increases in precipitation intensity in the future growing season will lead to scarce (surplus) water at different stages of crop growth. The joint exceedance frequency of compound events related to extreme heat is projected to increase by up to 15 days per season, while events of cool waves and drought co-occurring will reduce in the major croplands by the end of the 21st century. The significant increases in heat-related ACIs, reduction in the frequency of precipitation while intensities increase, and the increased frequency of compound events suggest global warming will pose immense challenges to crop production on the Canadian prairies.

https://hdl.handle.net/10388/16539