Shallow marine sediments play a critical role in regulating methane release, a potent greenhouse gas whose 100-year global warming potential is 25 times greater than that of carbon dioxide. This review synthesizes two decades of research to evaluate four major methane removal pathways: anaerobic oxidation of methane (AOM), aerobic oxidation of methane (AeOM), diffusion release, and ebullition release, alongside their respective contributions to global methane budgets. Sulfate-driven AOM (SR-AOM), which occurs at the sulfate-methane transition zone (SMTZ), dominates methane removal at a global rate of 33.68 Tg yr⁻¹, while AeOM in surface sediments acts as a secondary filter (≥7.16 Tg yr⁻¹). Diffusion release (0.42-5.5 Tg yr⁻¹) and ebullition release (9-27 Tg yr⁻¹) represent key methane emission pathways, with ebullition intensified by seabed erosion and ocean warming. This study systematically analyzes methodological advances and comparative performance of geochemical analysis, direct field statistics, and acoustic inversion techniques, and identifies key uncertainties stemming from sampling artifacts, signal inversion errors, and sediment spatial heterogeneity. Multiple environmental factors, including organic carbon loading, sulfate availability, temperature and pressure, collectively modulate the efficiency of sedimentary methane removal, primarily by regulating microbial activity. Shallow marine systems characterized by low sulfate concentrations and high organic carbon input are particularly susceptible to methane diffusion release. Tectonic activity and environmental perturbations such as warming and decompression substantially boost methane ebullition, highlighting the urgent need to address methane emissions amplified by global warming. Although global methane removal estimates reveal significant spatial variability, major data gaps remain, particularly for quantifying bubble-mediated ebullition fluxes. This study emphasizes the necessity of adopting high-resolution, multidisciplinary approaches to refine global methane budgets and predict climate-driven feedback effects. It also provides a research framework to fill existing knowledge gaps regarding methane dynamics in vulnerable coastal sedimentary systems.

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