The Climatic Impact of Projected Landuse Change in Western Canada Simulated by a Convection-Permitting Regional Climate Model under RCP8.5

Climate change in the Northern Hemisphere high latitudes are more prominent compared to other regions due to polar amplification. Accompanying the significant warming and the increase of the length of growing season is the expansion of agriculture activity to the northern Canadian Prairies and northward shift of the boreal forest biome by the end of century. To understand the projected land use changes’ impact on the regional climate over the Canadian Prairies provinces, we conducted a set of simulations including a control simulation with current climate and landuse, a RCP8.5 pseudo-global warming simulation, and a simulation with RCP8.5 climate forcing and projected changes in land-use with high-resolution convection-permitting WRF. The changes due to the global warming and those due to landuse change are investigated through cross comparison with simulations with current landuse distribution and projected landuse distribution in a high-end emission scenario RCP8.5 by the end of 21^stcentury. The main findings of the study indicate that the warming under RCP8.5 plays more important role in changing the hydrometeorological condition in western Canada, especially those related to temperature changes. Landuse change moderately change the surface air temperature, land-surface atmosphere exchange, and precipitation statistics. Landuse change, especially in regions with significant replacement of wooded tundra by forests, can significantly change the precipitation’s distribution in intensity. As for regions with insignificant changes in precipitation under RCP8.5, landuse change can play a significant role in regulate the seasonal cycle of precipitation.