This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Irrigating U.S. crops prevents higher greenhouse gas emissions by avoiding land conversion, new research by Colorado State University shows. Agricultural irrigation allows the United States to grow more food on less land.
If irrigation were suddenly shut off, the land-use change required to make up for lost yields would produce significantly more greenhouse gas emissions than irrigation emits—363 times more. CSU scientists estimate the emissions saved by avoiding land-use change would equate to 363 years' worth of today's U.S. annual greenhouse gas emissions from irrigation. Converting natural ecosystems to agricultural use releases carbon stored in soil and vegetation.
Land use and land conversion for agriculture to produce food, fiber and fuel contribute nearly a quarter of global greenhouse gas emissions, making the sector a key priority for emissions reductions, the study published in Proceedings of the National Academy of Sciences states. "It was clear from this work that irrigation has a net positive effect on emissions," said lead author Avery Driscoll, who conducted the research as a CSU Ph.D. student. "The avoided emissions from reductions in indirect land-use change were much greater than the direct emissions, and those could decline further with electrification." Pumping water for irrigation—both on farms and for interbasin transfers—uses energy, which produces most irrigation-related emissions.
This is also the easiest emissions source to address, the researchers said, by replacing fossil fuel pumps with electric pumps. They suggested policymakers might consider incentives for electrification when developing climate-smart agriculture programs. In previous studies, the researchers outlined direct emissions from irrigation, which also include smaller amounts of nitrous oxide released through microbial respiration and the dispersal of dissolved carbon dioxide when groundwater is sprayed on fields.
Their new research is the first study to compare the costs and benefits of direct and indirect emissions from irrigation. The avoided emissions due to irrigation amount to 6.86 gigatons—more than the total annual emissions of the U.S. in 2024 (5.91 gigatons), or about 13% of total global emissions that year, Driscoll said. The researchers said the study demonstrates that climate-smart agricultural policies must consider both direct and indirect emissions impacts.
"This comprehensive approach to accounting for direct emissions from the field and for the indirect land-use impacts lets us identify local opportunities to reduce emissions, through pump electrification and grid decarbonization, while also maximizing benefits associated with increasing productivity," said Driscoll, who is now a postdoctoral researcher at Purdue University. "Ideally, this is a win-win for addressing local emissions and also harnessing the global benefits of irrigation." To estimate the amount of land and emissions spared, the researchers first mapped yield benefits at the county level across the United States, calculating a ratio of rainfed to irrigated yields using existing survey data and a machine learning model. They then used a global economic model that simulates production, consumption and trade flows to determine how U.S. production would change if it were all rainfed.
Extract — continue reading at the source.
