Greenhouse gas emissions from US irrigation pumping and implications for climate-smart irrigation policy

Abstract

Irrigation reduces crop vulnerability to drought and heat stress and thus is a promising climate change adaptation strategy. However, irrigation also produces greenhouse gas emissions through pump energy use. To assess potential conflicts between adaptive irrigation expansion and agricultural emissions mitigation efforts, we calculated county-level emissions from irrigation energy use in the US using fuel expenditures, prices, and emissions factors. Irrigation pump energy use produced 12.6 million metric tonnes CO2e in the US in 2018 (90% CI: 10.4, 15.0), predominantly attributable to groundwater pumping. Groundwater reliance, irrigated area extent, water demand, fuel choice, and electrical grid emissions intensity drove spatial heterogeneity in emissions. Due to heavy reliance on electrical pumps, projected reductions in electrical grid emissions intensity are estimated to reduce pumping emissions by 46% by 2050, with further reductions possible through pump electrification. Quantification of irrigation-related emissions will enable targeted emissions reduction efforts and climate-smart irrigation expansion.

Global energy use and carbon emissions from irrigated agriculture

“…Furthermore, earlier studies have estimated irrigation energy consumption and GHG emissions specifically from irrigation in China 21 , India 22 , the Mediterranean region 23 , Pakistan 24 , and the United States 25 . However, there is a notable gap in studies providing global coverage of energy-related GHG emissions stemming from irrigation.…”