National CDR pathways for the land system in Germany: Potentials, effects and barriers to implementation

Carbon Dioxide Removal (CDR) is widely recognized as an essential component for meeting global climate targets, as emphasized in the latest IPCC reports. This is reflected in many national targets and NDCs, which regard LULUCF a key sector for achieving these goals. This sector includes land-intensive measures such as afforestation/reforestation, forest management, and BECCS, which are attributed great potentials for CO₂ sequestration. Consequently, these methods are primarily integrated into future scenarios to model global CDR potentials. However, existing modelling efforts focus mainly on the biophysical potentials of land-based CDR, while its implementation is also shaped by socioeconomic contexts (e.g., societal values, demand or policy measures) at the national level. These factors influence direct and indirect land-use change dynamics (e.g., displacement effects and land-sparing or land-sharing outcomes) and the provision of food, materials, and other ecosystem services.

The transdisciplinary research project STEPSEC investigates the feasibility of land-based CDR measures – BECCS, forest management, and afforestation/reforestation – under socio-ecological constraints in Germany. For this purpose, an agent-based model of the German land system (CRAFTY-DE) was developed to simulate the implications for future land use and its effects on ecosystem service provision. The demand for ecosystem services drives a range of interrelated land use agents with different behaviour and productivity that depend on scenario-specific dynamic socioeconomic and environmental conditions. Therefore, a set of national scenarios and policy assumptions has been developed using a co-creation process with stakeholders. These include a) qualitative and quantitative land-use-related Shared Socioeconomic Pathways and b) scenario-specific policy measures for CDR. These aspects have been introduced into the model in the form of socioeconomic and environmental location factors as well as incentives and restrictions for land use change.

The model provides a range of plausible CDR pathways for land use development in Germany. The results allow a scenario-dependent assessment of the CO₂ sequestration potential of land-based CDR in Germany. Furthermore, they clearly demonstrate the extent of CDR required, how this would shape future land use, and what potential impacts this would have on ecosystem services. In a final step, these national-scale findings were discussed with key land use stakeholders in Germany to identify potential barriers to the implementation of CDR at the local level.

The project’s transdisciplinary approach aimed to integrate practical expertise into model design to simulate the effects of political targets and measures on the land system and perform a reality check on the model results to evaluate the practical feasibility of CDR measures at local level. The talk focuses on challenges and opportunities of this transdisciplinary approach and presents key findings on land system potentials, effects and limitations of CDR implementation. Results show that even ambitious scenarios involve significant synergy and trade-off effects and are unlikely to achieve CDR targets in line with other goals (e.g. food security, energy supply). Furthermore, an implementation gap exists at national to local level, which can be attributed to four key sets of barriers: Limited resources; Regulatory, economic and social environment; Current and expected lines of conflict; Knowledge gaps in practice and research.