Nitrogen deposition contributed to a global increase in nitrous oxide emissions from forest soils

Abstract Nitrous oxide is a potent greenhouse gas. Anthropogenically enhanced nitrogen deposition causes natural forest soils to release more nitrous oxide, exacerbating global warming. We used data from nitrogen addition experiments conducted in forests worldwide to quantify the spatially varying sensitivity of soil nitrous oxide emission to nitrogen deposition, thereby inferring soil nitrous oxide emission dynamics from nitrogen deposition data. From 1985 to 2015, nitrous oxide emitted from global forest soils increased from 3.55 to 3.85 teragrams of nitrogen per year. Nitrogen deposition contributed directly to 9.0% of global forest soil nitrous oxide emissions. The derived country-specific sensitivities of soil nitrous oxide emission to nitrogen deposition could be employed as localized emission factors for forestland nitrous oxide emission inventories. This study sheds light on a process-augmented data-driven approach to estimating global nitrous oxide emissions by synthesizing experimental and observational data.