Multi-Model Assessment of Future Hydrogen Soil Deposition and Lifetime using CMIP6 Data by Brown et al. can be found here.
Abstract
Alternate energy carriers to fossil fuels are needed to mitigate climate change, of which hydrogen is one candidate if generated sustainably. However, if hydrogen leaks into the atmosphere, it can increase the amounts of other greenhouse gases, including methane, water vapour in the stratosphere, and ozone at surface levels. Approximately 70% of hydrogen is lost to microbes in the soil. Soil uptake is poorly constrained and has a large impact on how long hydrogen stays in the atmosphere, therefore affecting its overall climate impact.
This work looks at four future pathways from five global climate models to calculate soil uptake in the future. We find hydrogen soil uptake increases over the century, with larger increases for pathways with stronger climate effects, leading to shorter hydrogen soil lifetimes. Hydrogen soil uptake has a 20% spread between models, which is due to large differences in soil moisture and porosity. The change in global warming potential (GWP) is estimated from the different soil lifetimes and we find that the spread from different models results in a 33.3% range in the GWP under present day conditions, with a maximum decrease of 5.3% by the end of the century.