Global agricultural N2O emission reduction strategies deliver climate benefits with minimal impact on stratospheric O3 recovery
James Weber, James Keeble, Nathan Luke Abraham, David J. Beerling, Maria Val Martin
Abstract
Abstract Agricultural nitrous oxide (N 2 O) emission reduction strategies are required given the potency of N 2 O as a greenhouse gas. However, the growing influence of N 2 O on stratospheric ozone (O 3 ) with declining stratospheric chlorine means the wider atmospheric impact of N 2 O reductions requires investigation. We calculate a N 2 O emission reduction of 1.35 TgN 2 O yr -1 (~5% of 2020 emissions) using spatially separate deployment of nitrification inhibitors ($70–113 tCO 2 e −1 ) and crushed basalt (no-cost co-benefit) which also sequesters CO 2 . In Earth System model simulations for 2025–2075 under high (SSP3-7.0) and low (SSP1-2.6) surface warming scenarios, this N 2 O mitigation reduces NO x -driven O 3 destruction, driving regional stratospheric O 3 increases but with minimal impact on total O 3 column recovery. By 2075, the radiative forcing of the combined N 2 O and CO 2 reductions equates to a beneficial 9–11 ppm CO 2 removal. Our results support targeted agricultural N 2 O emission reductions for helping nations reach net-zero without hindering O 3 recovery.