- Main
Machine-learning-based estimates of global natural vegetated wetland methane emissions (2000–2025)
- Li, Mengze;
- Jackson, Robert B;
- Saunois, Marielle;
- Ciais, Philippe;
- Poulter, Ben;
- Canadell, Josep G;
- Patra, Prabir K;
- Tian, Hanqin;
- Zhang, Zhen;
- Fluet-Chouinard, Etienne;
- Ouyang, Zutao;
- Zhang, Ting;
- Beerling, David J;
- Belikov, Dmitry A;
- Bousquet, Philippe;
- Custodio, Danilo;
- Chandra, Naveen;
- Dou, Xinyu;
- Gedney, Nicola;
- Hopcroft, Peter O;
- Hoyt, Alison M;
- Ichii, Kazuhito;
- Ito, Akihito;
- Jain, Atul K;
- Jensen, Katherine;
- Joos, Fortunat;
- Kleinen, Thomas;
- Kondo, Masayuki;
- Li, Fa;
- Li, Tingting;
- Liu, Xiangyu;
- Maksyutov, Shamil;
- Malhotra, Avni;
- Martinez, Adrien;
- McDonald, Kyle;
- Melton, Joe R;
- Müller, Jurek;
- Niwa, Yosuke;
- Pan, Shufen;
- Peng, Shushi;
- Peng, Changhui;
- Qin, Zhangcai;
- Raymond, Peter;
- Riley, William;
- Segers, Arjo;
- Thompson, Rona L;
- Tsuruta, Aki;
- Xi, Yi;
- Yuan, Kunxiaojia;
- Zhang, Wenxin;
- Zheng, Bo;
- Zhu, Qing;
- Zhu, Qiuan;
- Zhuang, Qianlai
Published Web Location
https://doi.org/10.5194/essd-18-3507-2026Abstract
Wetlands are the largest natural source of atmospheric methane (CH 4 ), yet comprehensive global budgets are typically delayed by years, preventing a timely understanding of CH 4 sources, sinks, and trends. To reduce this delay, we present a model emulator-driven framework and accompanying workflow that enable timely, continuous emission updates using a machine-learning emulator to reconstruct spatially explicit monthly emission fields at 1° × 1° resolution. We apply this framework to a global dataset of natural vegetated wetland CH 4 emissions to extend the most recent Global Methane Budget (GMB; Saunois et al., 2025) record that covers the 2000–2020 emissions through 2025. In the test data (∼ 30 % of the total dataset), the emulator achieved a global R 2 of 0.65 ± 0.003 (mean ± 95 % CI, hereafter) and an RMSE of 5.49±0.12×10-3 Tg CH 4 yr −1 . The emulator is trained on 35 GMB model estimates, including 22 process-based models and 13 atmospheric inversions, paired with 10 ensemble realizations of 11 gridded climate predictor variables from atmospheric reanalyses. Our results show that the global mean predicted wetland CH 4 emissions for 2021–2025 (157.8 ± 2.4 Tg CH 4 yr −1 ) are not significantly higher (∼ 0.05 Tg CH 4 yr −1 ) than the 2000–2020 baseline. However, this stability masks a significant hemispheric redistribution of emissions. We detect an increase in Northern Hemisphere (NH) emissions in 2021–2025, with mid- and high-latitudes increasing by 0.76 ± 0.07 and 0.35 ± 0.03 Tg CH 4 yr −1 , respectively, while the tropics and Southern Hemisphere (SH) extratropics show offsetting negative trends (−0.95 ± 0.19 and -0.11±0.02 Tg CH 4 yr −1 , respectively). The predicted emissions are able to capture the low emissions in 2023 in South America linked to El Niño-related drought, as reported by recent studies (Ciais et al., 2026; Quinn et al., 2025). Furthermore, we identify a distinct seasonal amplification of global emission trends that peaks in late boreal summer. This new modeled dataset and operational framework bridge the gap between the latest updated budgets and low-latency monitoring, providing a scalable capacity to frequently update global emission estimates and critical early warnings of regional wetland feedback loops. The data are publicly available at https://doi.org/10.5281/zenodo.18870108 (Li et al., 2026).
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