Hydrogen is both an important energy carrier and a climate-relevant trace gas whose atmospheric abundance is rising. The rapid expansion of the global hydrogen economy necessitates better understanding of hydrogen cyclings. This session advances understanding of the global hydrogen cycle and its interactions with methane through measurements and modeling from individual sites to the globe. We welcome contributions quantifying hydrogen sources and sinks, including but not limited to soil uptake, atmospheric processes, geological emissions, and anthropogenic emissions from natural gas systems and the hydrogen industrial chain; studies developing novel observational approaches for concentration and flux measurements, as well as emerging sensor technologies for leak detection and quantification; and work on coupled H₂–CH₄ cycling, integrating observations with inverse modeling and Earth system models to better constrain hydrogen budgets and assess climate impacts. These efforts will contribute to updated global hydrogen budgets being developed under the umbrella of the Global Carbon Project.

• A - Atmospheric Sciences
• GC - Global Environmental Change