We document a substantial increase in global N2O emissions from mangroves. Based on our analysis of two decades of mangrove N2O emission studies, we estimate N2O emission of 0.023 Tg N year−1 from global mangrove ecosystems. N2O fluxes from mangrove ecosystems are strongly increased by sediment dissolved inorganic nitrogen (DIN) concentration transported from river catchments to coastal waters. Continuing growth of nutrient inputs from anthropogenic sources, i.e., agricultural intensification, excessive fertilizer use and waste water discharge, will appreciably increase DIN loading and consequently global N2O emission from mangroves. Based on the Millennium Ecosystem Assessment scenarios of riverine DIN inputs into mangrove ecosystems coupled with our estimates of DIN-controlled emissions rates, we expect N2O emission to increase by 20%–51% by 2030 and 27%–74% by 2050 compared with estimated emissions in the year 2000. These forecasts underline the urgency of improvements in catchment-scale nitrogen management strategies.
Bibliographical noteFunding Information:
We acknowledge the support from the European Union's Horizon 2020 Research and Innovation Program under the Marie Sk?odowska-Curie grant agreement no. 734317 (HiFreq), the University of Birmingham's Institute for Global Innovation, and Cardiff University's Darlithwyr Disglair Program. S.M.G. was supported by the US National Science Foundation under grant ICER/EAR-1829999 to Stanford University. Any opinions, findings, and conclusions or recommendations expressed in this material do not necessarily reflect the views of the funding organizations. We also thank Chantal Jackson for her support in producing the figures and thank Sybil Seitzinger and Emilio Mayorga for providing the NEWS 2 data. Conceptualization, F.M. S.K. and S.U.; methodology, F.M. S.K. and S.U.; writing ? original draft, F.M. S.K. and S.U.; writing ? review & editing, F.M. S.K. S.U. D.M.H. and S.M.G.; formal analysis, F.M.; visualization, F.M. The authors declare no competing interests.
© 2021 Elsevier Inc.
- climate change
- greenhouse gas
- nitrous oxide
- river catchments
ASJC Scopus subject areas
- Environmental Science(all)
- Earth and Planetary Sciences (miscellaneous)