Agent-based modelling of alternative futures in the German land system: What are the socioecological impacts of land-based Carbon Dioxide Removal?

To achieve net-zero greenhouse gas emissions in the future, carbon dioxide removal (CDR), also known as negative CO₂ emissions, is likely to become an essential part of the climate mitigation portfolio. In Germany, land-based CDR options such as bioenergy with carbon capture and storage (BECCS), agroforestry, forest management, and afforestation/reforestation are increasingly being discussed and integrated into potential future scenarios. However, it remains unclear how these options will affect future land use in Germany and what impacts this will have on ecosystem service provision.

Depending on future socioeconomic development and the progression of climate change, Germany can follow different paths for implementing CDR in the land system. We use a set of stakeholder-developed qualitative and quantitative CDR visions and Shared Socioeconomic Pathways (SSPs) combined with climate change scenarios to simulate the future land use change in Germany concerning afforestation/reforestation, forest management, agroforestry, and BECCS. For this, we develop CRAFTY-DE, a new agent-based model of the German land system that integrates a wide range of available land use/cover data and operates at a 1 km² resolution. Here, the demand for ecosystem services drives a range of interrelated land use agents with different productivities and dependencies on changing socio-economic and environmental conditions.

With CRAFTY-DE, we simulate the conditions under which CDR targets can be achieved in the German land system. In particular, we investigate the role of selected policy measures. Our research addresses the following questions: Which scenarios offer favourable conditions for which CDR measures and thus synergies between ecosystem services? How can specific policy measures support this? What are the trade-offs and land use conflicts associated with CDR measures?

Identifying possible pathways of land use change and the resulting synergies and trade-offs associated with CDR will become an important knowledge base for policymakers, industry, and stakeholders regarding the scope for action in the development of land-based CDR in Germany.