Abstract
Methane (CH4) is a potent greenhouse gas with a warming potential 84 times that of carbon dioxide (CO2) over a 20-year period. Atmospheric CH4 concentrations have been rising since the nineteenth century but the cause of large increases post-2007 is disputed. Tropical wetlands are thought to account for ∼20% of global CH4 emissions, but African tropical wetlands are understudied and their contribution is uncertain. In this work, we use the first airborne measurements of CH4 sampled over three wetland areas in Zambia to derive emission fluxes. Three independent approaches to flux quantification from airborne measurements were used: Airborne mass balance, airborne eddy-covariance, and an atmospheric inversion. Measured emissions (ranging from 5 to 28 mg m−2 hr−1) were found to be an order of magnitude greater than those simulated by land surface models (ranging from 0.6 to 3.9 mg m−2 hr−1), suggesting much greater emissions from tropical wetlands than currently accounted for. The prevalence of such underestimated CH4 sources may necessitate additional reductions in anthropogenic greenhouse gas emissions to keep global warming below a threshold of 2°C above preindustrial levels.
Original language | English |
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Article number | e2021GB007261 |
Number of pages | 21 |
Journal | Global Biogeochemical Cycles |
Volume | 36 |
Issue number | 6 |
DOIs | |
Publication status | Published - 10 Jun 2022 |
Bibliographical note
Funding Information:The aircraft data used in this publication have been collected as part of the Methane Observations and Yearly Assessments (MOYA) project funded by the Natural Environment Research Council (NERC) under Grant No. NE/N015835/1 (The University of Manchester) and NE/N016211/1 (Royal Holloway, University of London), as well as the NERC ZWAMPS project (NE/S00159X/1). MFL and PIP also acknowledge funding from MOYA (NE/N015916/1) and the NERC National Centre for Earth Observation (NE/R016518/1). AG is funded by a NERC Independent Research Fellowship (NE/L010992/1). RJP is funded via the UK National Centre for Earth Observation (NE/N018079/1 and NE/R016518/1). NG acknowledges funding from MOYA and from The Newton Fund via the Met Office Climate Science for Service Partnership Brazil (CSSP Brazil). SM acknowledges the National Ecological Observatory Network (NEON), a program sponsored by the National Science Foundation and operated under cooperative agreement by Battelle. This material is based in part upon work supported by the National Science Foundation through the NEON Program. We would like to thank Airtask Ltd. (who flew the aircraft),and all those involved in the operation and maintenance of the BAe-146-301 Atmospheric Research Aircraft including FAAM, Avalon Aero, UK Research and Innovation (UKRI) and the University of Leeds. We also thank The Zambian Geological Survey, Ministry of Mines, Zambia for their very strong support and participation in all stages of the work in Zambia. We would like to thank the Japanese Aerospace Exploration Agency, National Institute for Environmental Studies, and the Ministry of Environment for the GOSAT data and their continuous support as part of the Joint Research Agreement. This research used the ALICE High Performance Computing Facility at the University of Leicester for the GOSAT retrievals. GCP land surface model work contributions: CTEM, Joe Melton, Vivek Arora; DLEM, Hanqin Tian, Hao Shi; ELM, William Riley, Qing Zhu; JSBACH, Thomas Kleinen; JULES, Nicola Gedney; LPJ-GUESS, Paul Miller, Wenxin Zhang; LPJ-MPI, Thomas Kleinen; LPJ-wsl, Ben Poulter, Zhen Zhang; LPX-Bern, Jurek Muller, Fortunat Joos; ORCHIDEE, Sushi Peng; TEM-MDM, Qianlai Zhuang, Licheng Liu; TRIPLEX-GHG, Changhui Peng, Qiuan Zhu; VISIT, Akihiko Ito.Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of their respective institutions.
Funding Information:
The aircraft data used in this publication have been collected as part of the Methane Observations and Yearly Assessments (MOYA) project funded by the Natural Environment Research Council (NERC) under Grant No. NE/N015835/1 (The University of Manchester) and NE/N016211/1 (Royal Holloway, University of London), as well as the NERC ZWAMPS project (NE/S00159X/1). MFL and PIP also acknowledge funding from MOYA (NE/N015916/1) and the NERC National Centre for Earth Observation (NE/R016518/1). AG is funded by a NERC Independent Research Fellowship (NE/L010992/1). RJP is funded via the UK National Centre for Earth Observation (NE/N018079/1 and NE/R016518/1). NG acknowledges funding from MOYA and from The Newton Fund via the Met Office Climate Science for Service Partnership Brazil (CSSP Brazil). SM acknowledges the National Ecological Observatory Network (NEON), a program sponsored by the National Science Foundation and operated under cooperative agreement by Battelle. This material is based in part upon work supported by the National Science Foundation through the NEON Program. We would like to thank Airtask Ltd. (who flew the aircraft),and all those involved in the operation and maintenance of the BAe‐146‐301 Atmospheric Research Aircraft including FAAM, Avalon Aero, UK Research and Innovation (UKRI) and the University of Leeds. We also thank The Zambian Geological Survey, Ministry of Mines, Zambia for their very strong support and participation in all stages of the work in Zambia. We would like to thank the Japanese Aerospace Exploration Agency, National Institute for Environmental Studies, and the Ministry of Environment for the GOSAT data and their continuous support as part of the Joint Research Agreement. This research used the ALICE High Performance Computing Facility at the University of Leicester for the GOSAT retrievals. GCP land surface model work contributions: CTEM, Joe Melton, Vivek Arora; DLEM, Hanqin Tian, Hao Shi; ELM, William Riley, Qing Zhu; JSBACH, Thomas Kleinen; JULES, Nicola Gedney; LPJ‐GUESS, Paul Miller, Wenxin Zhang; LPJ‐MPI, Thomas Kleinen; LPJ‐wsl, Ben Poulter, Zhen Zhang; LPX‐Bern, Jurek Muller, Fortunat Joos; ORCHIDEE, Sushi Peng; TEM‐MDM, Qianlai Zhuang, Licheng Liu; TRIPLEX‐GHG, Changhui Peng, Qiuan Zhu; VISIT, Akihiko Ito.Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of their respective institutions.
Publisher Copyright:
© 2022. The Authors.
Keywords
- Africa
- emission flux
- methane
- model comparison
- satellite
- wetlands