How effective and efficient is the generation of nature-based carbon removal quantified according to the regulation on carbon removal and carbon farming certification? An evaluation based on the example of a hypothetical agroforestry system in Baden-Württemberg

Abstract

Nature-based carbon removal (CR) could play a key role in achieving climate neutrality but it does face quantification challenges. This study evaluates the effectiveness and efficiency of CR quantification under the Carbon Removals and Carbon Farming (CRCF) Regulation, using Baden-Württemberg (Germany) as a case study. We designed a hypothetical agroforestry system for valuable timber production compliant with the CRCF requirements, modelling potential GHG emission reductions and the benefit-potential ratio (share of the CRCF-compliant net CR benefit within the total GHG emission mitigation potential). The results revealed a significant shortfall between the total GHG mitigation potential (350 kt CO₂eq) and the actual net CR benefit (205 kt CO₂eq), representing only 5 % of BW’s agricultural emissions. The benefit-potential ratio was at most 59 %, with abatement costs ranging from €59 to €153 t CO₂eq^-1. Conservative estimates to improve reliability further lowered the ratio to 24 %, pushing costs to €244 t CO₂eq^-1. While agroforestry does manifest regional CR generation potential, it is unlikely to contribute significantly to large-scale CR under the current CRCF framework, as both flaws within its quantification base and the inherent properties of nature-based CR limit its effectiveness. Although transferability is restricted by focusing on valuable timber production in BW, our results highlighted the need for harmonized emission factors, system boundary definitions (particularly indirect land use change), and a clear distinction between CR (e.g., from carbon sequestration in soils) and reduced soil emissions. We advocate balancing the use of agroforestry with more durable CR strategies and imposing caps on nature-based CR contributions to ensure robust climate action.