Global greenhouse gas emissions from agriculture: pathways to sustainable reductions

Authors: LI, LIDONG - University Of Nebraska; AWADA, TALA - University Of Nebraska; SHI, YEYIN - University Of Nebraska; Jin, Virginia; KAISER, MICHAEL - University Of Nebraska

Submitted to: Global Change Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2024
Publication Date: 12/27/2024
Citation: Li, L., Awada, T., Shi, Y., Jin, V.L., Kaiser, M. 2024. Global greenhouse gas emissions from agriculture: pathways to sustainable reductions. Global Change Biology. 31(1). Article e70015. https://doi.org/10.1111/gcb.70015.
DOI: https://doi.org/10.1111/gcb.70015

Interpretive Summary: Sustainable intensification of agricultural production plays a key role in reducing the total greenhouse gas (GHG) emissions contributed to the atmosphere as a result of meeting global demands for food, fiber, and energy. Here, we used global GHG emissions data from the United Nations Food and Agriculture Organization to evaluate the impacts of agricultural management on agricultural GHG emissions from 1990 to 2021. We then projected agricultural GHG emissions for 2022 to 2050 under three different scenarios: (1) no change in management or land use practices, (2) 100% decrease in forestlands converted to agricultural land use, and (3) 200% decrease in forestland conversion to agriculture. Decreasing land use change from forest to agriculture was the key factor that helped slow the rate of agricultural GHG emissions from 1990 to 2021. In all future scenarios, emissions from agriculture increased through 2050. Slowing the rate of land use change from forest to agriculture by 100% maintained agricultural GHG emissions by 2050, whereas slowing land use change by 200% decreased agricultural GHG emissions 17% compared to scenarios with no change in current land use or management. Intensification of agricultural production on existing arable lands and decreasing land use conversion from forest to agriculture are key drivers to maintain or decrease agricultural GHG emissions in the future.

Technical Abstract: Agriculture serves as both a source and a sink of global greenhouse gases (GHGs), with agricultural intensification continuing to contribute to global GHG emissions. Climate-smart agriculture, encompassing both nature- and technology-based, offers promising solutions to mitigate GHG emissions and adapt to climate change. In this paper, we synthesized global data from the Food and Agriculture Organization (FAO) of the United Nations between 1990 and 2021 to analyze the impacts of agricultural activities on global GHG emissions from agricultural land, using structural equation modeling. We then obtained predictive estimates of agricultural GHG emissions for the future period of 2022 to 2050 using a deep learning model. Our results indicate that, from 1990 to 2021, global livestock numbers, inorganic N fertilizer use, crop residue, and irrigation area increased by 27, 47, 49, and 37%, respectively, contributing to GHG emissions. However, overall agricultural GHG emissions declined from 11.50 to 10.89 GtCO2eq, due mainly to a 29% reduction in net forest loss to agriculture during this period. If current agricultural trends continue to persist, our model predicts that GHG emissions will rise to 11.82 ± 0.07 GtCO2eq in 2050. However, maintaining agricultural GHG emissions at the 2021 level through 2050 is possible if the rate of reduction in net forest loss is doubled. Further, if the rate is tripled, agricultural GHG emissions could be limited to 9.85 ± 0.07 GtCO2eq in 2050. Our findings demonstrate that sustainable agricultural intensification, alongside environmental impact mitigation, can be realized through accelerated forest conservation and the adoption of climate-smart agricultural practices.