Emergent methane mitigation and removal approaches: A review

Early control of atmospheric methane is essential to achieving a 1.5 °C warming pathway. This paper considers a range of academic and gray literature reviews of methane control techniques, as a starting point for a more comprehensive, integrative review. Novel approaches are considered across anthropogenic and natural sources; where these are lacking, existing approaches are discussed. Four principal sectors meriting action and research are identified: mining and oil & gas emissions, agriculture (including near-term minor interventions and future synthetic food production), effective waste management, and interventions in natural methane sources (e.g., permafrost, methane clathrates, and wetlands). Where abatement is impractical, this review discusses speculative geoengineering technologies (e.g., enhancing the •OH and •Cl sinks, photocatalysis, and adsorbent air capture). Atmospheric methane removal proposals merit research, but may remain impractical due to methane concentrations and lifetime.