Effect of irrigation development on greenhouse gas emissions in Alberta and Saskatchewan

Abstract

Irrigation can be a major emitter of greenhouse gases, and can contribute to global climate change. Most studies dealing with the evaluation of irrigation projects worldwide have not taken this aspect of irrigation development into account. In this study, changes in greenhouse gas emissions from converting a given area from dryland into irrigated acreage in Alberta and Saskatchewan were estimated. A systems approach was used in which changes in crop production mix are considered in terms of induced livestock production, increased input demand, and other induced economic activities. A modified Canadian Economic and Emissions Model for Agriculture was employed to estimate the change in emissions. The net contribution of irrigation to emissions of three major greenhouse gases (GHG): carbon dioxide, methane, and nitrous oxide was estimated. Results suggest that each hectare of land converted into irrigation leads directly to an additional emission of major GHG of 1.68-2.61 t yr-1 (in carbon dioxide equivalents). When various indirect and induced sources of emissions were included with the direct emissions, irrigation's net emission level is 3.35-3.65 t ha-1 yr-1 (in carbon dioxide equivalents). Additionally, storage reservoirs, developed for supplying water to these irrigation projects, could also be associated with emissions of GHGs. Considering all these sources, irrigation adds 3.7% and 6.5% of total (agriculture and agri-food sector level) GHG emissions in Saskatchewan and Alberta, respectively. This has implications for the assessment of future irrigation projects from an environmental perspective.