Monitoring CO2 Concentrations in Soil Gas: A Novel MRV Approach for Cropland-Based ERW?

• DOI: 10.31223/x5267r
• Publication Date: 2023-12-07T07:40:07Z
• Authors: Dirk Paessler; Ralf Steffens; Jens Hammes; Ingrid Smet

This paper discusses the challenges we have faced in the past 2.5 years of field experiments trying to measure the speed of Enhanced Rock Weathering (ERW) in agricultural settings for removing CO₂ from the atmosphere. Traditional measurements that allow quantification of carbon dioxide removal (CDR) in laboratory ERW tests include chemical analyses of the leached out soil water and monitoring with electronic pH and EC soil sensors. Unfortunately, application of these methods on our ERW field experiments has not given us any results, and it seems that it may take several more years for a relevant ERW signal to emerge. As an alternative quantification method, we used CO₂ sensors placed inside the soil in combination with automated CO₂ flux meters on top of the soil as a new way to assess the CDR effects resulting from ERW treatments in agricultural settings. This novel approach could provide a faster way to assess the effectiveness of ERW in removing CO₂ from the atmosphere. And in turn, this would expedite ERW experiments as it could make large-scale/multi-variant experiments feasible and eventually become a new methodology for MRV (monitoring, reporting and verification) of ERW. This approach may also enable a faster collection of the large datasets that are needed for the creation, calibration and validation of accurate ERW models.