Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 13, 977-990, 2017
https://doi.org/10.5194/cp-13-977-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
28 Jul 2017
Preindustrial nitrous oxide emissions from the land biosphere estimated by using a global biogeochemistry model
Rongting Xu1, Hanqin Tian1, Chaoqun Lu2, Shufen Pan1,3, Jian Chen4,1, Jia Yang1, and Bowen Zhang1 1International Center for Climate and Global Change Research and School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL 36849, USA
2Department of Ecology, Evolution, & Organismal Biology, Iowa State University, Ames, IA 50011, USA
3State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
4Department of Geosciences, College of Sciences and Mathematics, Auburn University, Auburn, AL 36849, USA
Abstract. To accurately assess how increased global nitrous oxide (N2O) emission has affected the climate system requires a robust estimation of the preindustrial N2O emissions since only the difference between current and preindustrial emissions represents net drivers of anthropogenic climate change. However, large uncertainty exists in previous estimates of preindustrial N2O emissions from the land biosphere, while preindustrial N2O emissions on the finer scales, such as regional, biome, or sector scales, have not been well quantified yet. In this study, we applied a process-based Dynamic Land Ecosystem Model (DLEM) to estimate the magnitude and spatial patterns of preindustrial N2O 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 preindustrial N2O emission was approximately 6.20 Tg N yr−1, with an uncertainty range of 4.76 to 8.13 Tg N yr−1. The estimated N2O emission varied significantly at spatial and biome levels. South America, Africa, and Southern Asia accounted for 34.12, 23.85, and 18.93 %, respectively, together contributing 76.90 % of global total emission. The tropics were identified as the major source of N2O released into the atmosphere, accounting for 64.66 % of the total emission. Our multi-scale estimates provide a robust reference for assessing the climate forcing of anthropogenic N2O emission from the land biosphere

Citation: Xu, R., Tian, H., Lu, C., Pan, S., Chen, J., Yang, J., and Zhang, B.: Preindustrial nitrous oxide emissions from the land biosphere estimated by using a global biogeochemistry model, Clim. Past, 13, 977-990, https://doi.org/10.5194/cp-13-977-2017, 2017.
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Short summary
As N2O emissions were present in preindustrial times, only the difference between current and preindustrial emissions represents net human-induced climate change. Large uncertainty exists in previous estimates of preindustrial N2O emissions from the land biosphere. Our estimate using process-based model was the first study that provided the preindustrial N2O emission at the biome, sector or country, and global level, which could be a useful reference for future climate mitigation.
As N2O emissions were present in preindustrial times, only the difference between current and...
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