Future Changes in the Surface Water Balance over Western Canada Using the CanESM5 (CMIP6) Ensemble for the Shared Socioeconomic Pathways 5 Scenario

Soumik Basu,David J Sauchyn

doi:10.3390/w14050691

Abstract

The Prairie provinces of Canada have about 80% of Canada’s agricultural land and contribute to more than 90% of the nation’s wheat and canola production. A future change in the surface water balance over this region could seriously affect Canada’s agro-economy. In this study, we examined 25 ensemble members of historical (1975 to 2005), near future (2021–2050), far future (2050–2080), and end of the century (2080–2100) simulations of the Canadian Earth System Model version 5 (CanESM5) from the Coupled Model Intercomparison Project Phase 6 (CMIP6). A comprehensive analysis of a new Net Water Balance Index (NWBI) indicates an increased growing season dryness despite increased total precipitation over the Prairie provinces. Evapotranspiration increases by 100–300 mm with a 10–20% increase in moisture loss due to transpiration. Total evaporation decreases by 15–20% as the fractional contribution of evaporation from soil decreases by 20–25%. Total evaporation from vegetation increases by 10–15%. These changes in the surface water balance suggest enhanced plant productivity when soil moisture is sufficient, but evaporative water loss that exceeds precipitation in most years.

Highlights

Climate change may have a severe effect on food production at mid and high latitudes (FAO, 2016), including Canada where more than 80% of the agricultural land is located in the Prairie Provinces (Figure 1) at latitudes of 49◦ to 54◦ N [1]
We examined future projections of the water balance for western Canada, which includes the Prairie provinces and British Columbia
We used 25 ensemble members of Canadian Earth System Model version 5 (CanESM5) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) archive for historical simulations and future scenarios based on the emission pathway SSP5

Summary

Introduction

Climate change may have a severe effect on food production at mid and high latitudes (FAO, 2016), including Canada where more than 80% of the agricultural land is located in the Prairie Provinces (Figure 1) at latitudes of 49◦ to 54◦ N [1]. Considerable technological innovation and adaptation of farming methods transferred from more temperate climates have produced a commercially viable agricultural industry in this continental interior on the northern margin of the world’s agricultural ecumene. According to Farm Credit Canada (2019), it is among the four largest exporters of wheat and the world’s largest exporter of canola for human consumption. More than 90% of Canada’s wheat and canola production is in the Prairies provinces of Alberta, Saskatchewan, and Manitoba [1].

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Results

Conclusion