Microbial Functional Gene Abundance‐Integrated Modeling of Global Methane Sinks in Upland Soils Under Future Climate Change

Abstract

Methanotrophs are key microbial regulators of soil methane (CH 4 ) sinks, but the global impact of their functional gene abundance on CH 4 oxidation remains unquantified. This gap limits the integration of key functional genes abundance parameters (e.g., pmoA ) into soil CH 4 sink model. We integrated meta‐analysis, machine learning, and process‐based modeling to assess the relationship between pmoA gene abundance and soil CH 4 uptake. Our developed Functional Gene Abundance‐Based Methanotrophy Model (FGA‐MeMo) incorporates pmoA as a proxy for CH 4 oxidation capacity, significantly improving model simulations. FGA‐MeMo estimates global upland soil CH 4 uptake at 45.74 ± 0.26 Tg year −1 , which is 56%–58% higher than MeMo model. Under SSP5‐8.5 scenario, this increases to 64.68 ± 0.35 Tg year −1 by 2100, with mid‐ and high‐latitude regions showing enhanced CH 4 oxidation due to greater pmoA abundance. These findings highlight the importance of integrating microbial functional genes into Earth system models for improved CH 4 cycle predictions.

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