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Gao Y, Burke EJ, Chadburn SE, Raivonen M, Markkanen T, Aurela M, Flanagan LB, Fortuniak K, Humphreys E, Lohila A, Li T, Mammarella I, Nevalainen O, Nilsson MB, Pawlak W, Tsuruta A, Yang H, Aalto T. Assessing modelled methane emissions over northern wetlands by the JULES-HIMMELI model. THE SCIENCE OF THE TOTAL ENVIRONMENT 2025; 980:179526. [PMID: 40318373 DOI: 10.1016/j.scitotenv.2025.179526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2024] [Revised: 03/31/2025] [Accepted: 04/22/2025] [Indexed: 05/07/2025]
Abstract
Northern wetlands are considered to be one of the most significant natural sources of methane (CH4) emissions. The default wetland CH4 emission scheme in JULES, a current state-of-art land surface model, only takes into account the CH4 emissions from inundated wetland areas in a simple manner based on soil temperature and substrate availability. In this work, a process-based peatland CH4 emission model HIMMELI was integrated with JULES, and the HIMMELI parameters were optimized with measured CH4 flux at six northern wetland sites for each site separately or multi-sites simultaneously. The simulated CH4 emission was significantly improved when using the optimized parameter values, with the bias of 54.88 mg m-2 d-1 averaged across all the studied sites in the simulation using the default parameter (DPR) values being reduced to -0.70 mg m-2 d-1 in the simulations using parameters values derived from the single site optimization (SSO) for each site. In the simulations using parameters values from the averages of single site optimization (SSO_AVG) and the multi-site optimization (MSO), the biases averaged across all the studied sites were -7.39 mg m-2 d-1 and -8.36 mg m-2 d-1, respectively. The MSO simulations demonstrated more stable root mean square error (RMSE) between the simulated and observed methane emissions than the SSO_AVG simulations over the studied sites, when the RMSEs of SSO simulations were used as reference points. To further reduce the uncertainties in the simulated CH4 emissions by the JULES-HIMMELI model, model processes related to the environment conditions (e.g. water table, soil carbon and vegetation) of wetland and northern wetland CH4 emission processes (e.g. snow and ice covering effect) are suggested to be improved in JULES and HIMMELI, respectively. This study presents a comprehensive analysis of the impact of different parameters on the CH4 emission in the JULES-HIMMELI model and obtains optimal parameter values for modelling CH4 emissions at the studied northern wetlands. These findings pave the way for accurate regional estimates of northern wetland CH4 emission.
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Affiliation(s)
- Yao Gao
- Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland; Department of Civil Engineering, University of Hongkong, Hong Kong, China.
| | | | | | - Maarit Raivonen
- Institute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, P.O. Box 68, 00014 Helsinki, Finland
| | - Tiina Markkanen
- Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland
| | - Mika Aurela
- Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland
| | - Lawrence B Flanagan
- Department of Biological Sciences, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, Canada
| | - Krzysztof Fortuniak
- Department of Meteorology and Climatology, Faculty of Geographical Sciences, University of Lodz, Lodz, Poland
| | - Elyn Humphreys
- Department of Geography and Environmental Studies, Carleton University, Ottawa, Canada
| | - Annalea Lohila
- Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland; Institute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, P.O. Box 68, 00014 Helsinki, Finland
| | - Tingting Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Ivan Mammarella
- Institute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, P.O. Box 68, 00014 Helsinki, Finland
| | - Olli Nevalainen
- Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland
| | - Mats B Nilsson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden
| | - Włodzimierz Pawlak
- Department of Meteorology and Climatology, Faculty of Geographical Sciences, University of Lodz, Lodz, Poland
| | - Aki Tsuruta
- Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland
| | - Huiyi Yang
- Livelihoods and Institutions Department, Natural Resources Institute, Faculty of Engineering & Science, University of Greenwich, UK
| | - Tuula Aalto
- Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland
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Schuster L, Taillardat P, Macreadie PI, Malerba ME. Freshwater wetland restoration and conservation are long-term natural climate solutions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 922:171218. [PMID: 38423329 DOI: 10.1016/j.scitotenv.2024.171218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/23/2023] [Accepted: 02/21/2024] [Indexed: 03/02/2024]
Abstract
Freshwater wetlands have a disproportionately large influence on the global carbon cycle, with the potential to serve as long-term carbon sinks. Many of the world's freshwater wetlands have been destroyed or degraded, thereby affecting carbon-sink capacity. Ecological restoration of degraded wetlands is thus becoming an increasingly sought-after natural climate solution. Yet the time required to revert a degraded wetland from a carbon source to sink remains largely unknown. Moreover, increased methane (CH4) and nitrous oxide (N2O) emissions might complicate the climate benefit that wetland restoration may represent. We conducted a global meta-analysis to evaluate the benefits of wetland restoration in terms of net ecosystem carbon and greenhouse gas balance. Most studies (76 %) investigated the benefits of wetland restoration in peatlands (bogs, fens, and peat swamps) in the northern hemisphere, whereas the effects of restoration in non-peat wetlands (freshwater marshes, non-peat swamps, and riparian wetlands) remain largely unexplored. Despite higher CH4 emissions, most restored (77 %) and all natural peatlands were net carbon sinks, whereas most degraded peatlands (69 %) were carbon sources. Conversely, CH4 emissions from non-peat wetlands were similar across degraded, restored, and natural non-peat wetlands. When considering the radiative forcings and atmospheric lifetimes of the different greenhouse gases, the average time for restored wetlands to have a net cooling effect on the climate after restoration is 525 years for peatlands and 141 years for non-peat wetlands. The radiative benefit of wetland restoration does, therefore, not meet the timeframe set by the Paris Agreement to limit global warming by 2100. The conservation and protection of natural freshwater wetlands should be prioritised over wetland restoration as those ecosystems already play a key role in climate change mitigation.
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Affiliation(s)
- Lukas Schuster
- School of Life and Environmental Sciences, Deakin University VIC 3125, Australia.
| | - Pierre Taillardat
- NUS Environmental Research Institute, National University of Singapore, Singapore 117411, Singapore
| | - Peter I Macreadie
- School of Life and Environmental Sciences, Deakin University VIC 3125, Australia
| | - Martino E Malerba
- School of Life and Environmental Sciences, Deakin University VIC 3125, Australia
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