Unveiling cascading lag effects of wetland methane emissions: Evidence from Lake Chad in Africa.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 42525760.
- Also identified by DOI 10.1126/sciadv.adx9866 and PMC identifier 13418730.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Wetland methane (CH<sub>4</sub>) emission seasonality is a major yet uncertain component of the global CH<sub>4</sub> seasonal cycle, with its quantification primarily limited by the challenges in accurately characterizing wetland dynamics and emission processes. Here, we proposed a remote sensing-based framework to analyze the seasonality of tropical wetland CH<sub>4</sub> emission systems by integrating satellite methane inversions with high-resolution wetland inundation mapping (distinguishing open water and inundated vegetation). Our results reveal a strong seasonal amplitude (4.75 teragrams per year) and pronounced seasonal hysteresis between precipitation and CH<sub>4</sub> emissions (7 months) in Lake Chad. We demonstrate that the cascading chain of precipitation-wetland inundation-vegetation succession-CH<sub>4</sub> emissions drives emission seasonality, characterized by a 3-month lag from precipitation to wetland inundation and a subsequent 4-month lag from inundation to peak emissions. These findings provide comprehensive and mechanistically generalizable insights into tropical wetland CH<sub>4</sub> seasonality and offer critical constraints for improving tropical CH<sub>4</sub> flux estimates.