Estimation of pre-industrial nitrous oxide emissions from the land biosphere
Other literature type
(issn: 1814-9332, eissn: 1814-9332)
To accurately assess how increased global nitrous oxide (N<sub>2</sub>O) emission has affected the climate system requires a robust estimation of the pre-industrial N<sub>2</sub>O emissions since only the difference between current and pre-industrial emissions represents net drivers of anthropogenic climate change. However, large uncertainty exists in previous estimates of pre-industrial N<sub>2</sub>O emissions from the land biosphere, while pre-industrial N<sub>2</sub>O emissions at the finer scales such as regional, biome, or sector have not yet well quantified. In this study, we applied a process-based Dynamic Land Ecosystem Model (DLEM) to estimate the magnitude and spatial patterns of pre-industrial N<sub>2</sub>O fluxes at the biome-, continental-, and global-level as driven by multiple environmental factors. Uncertainties associated with key parameters were also evaluated. Our study indicates that the mean of the pre-industrial N<sub>2</sub>O emission was approximately 6.20 Tg N yr<sup>−1</sup>, with an uncertainty range of 4.76 to 8.13 Tg N yr<sup>−1</sup>. The estimated N<sub>2</sub>O emission varied significantly at spatial- and biome-levels. South America, Africa, and Southern Asia accounted for 34.12 %, 23.85 %, 18.93 %, respectively, together contributing of 76.90 % of global total emission. The tropics were identified as the major source of N<sub>2</sub>O released into the atmosphere, accounting for 64.66 % of the total emission. Our multi-scale estimates with a reasonable uncertainty range provides a robust reference for assessing the climate forcing of anthropogenic N<sub>2</sub>O emission from the land biosphere.