Agent-based modelling of alternative futures in the German land use system: Can carbon dioxide removal through land benefit society and the environment?

Abstract

To reach net zero greenhouse gas emissions in the future, carbon dioxide removal (CDR), also known as negative emissions, will very likely become an additional but inevitable part of the climate mitigation portfolio. In Germany, land-based CDR option such as bioenergy with carbon capture and storage, agroforestry, afforestation and reforestation are increasingly being discussed and integrated into possible future scenarios. However, it remains unclear how such options will affect future land use change in Germany and what impacts this will have on food and material production as well as other ecosystem services. Depending on future socioeconomic development but also on the advance of climate change, Germany can follow different paths of implementing CDR measures in the land system.

Here we take a set of stakeholder-developed, qualitative and quantitative CDR-related visions and Shared Socioeconomic Pathways (SSPs) in combination with climate change scenarios, to simulate the development of the German land system with respect to bioenergy, agroforestry, and afforestation/reforestation. We develop CRAFTY-DE, a new agent-based model of the German land system that brings together a broad range of available land use/cover data and operates at a 1 km² resolution. CRAFTY-DE is an application of the globally-embedded CRAFTY agent-based modelling framework. By modelling the future of the German land system with CRAFTY-DE, we simulate how pathways of time-dependent actions might achieve CDR-related visions in Germany. We investigate which choice and proportions of land-based CDR methods best manage to reconcile climate mitigation, food security and environmental protection.

Identifying possible pathways of land use development along with arising synergies and trade-offs between CDR-related land uses in terms of their impact on society and the environment will become an important knowledge base about the scope for action in developing land-based CDR in Germany, for policy makers, industry and stakeholders.