Scrutinizing the feasibility of terrestrial CDR potentials under socio-ecological constraints
To limit global warming to well below 2°C in line with the Paris Agreement, it is assumed that large-scale carbon dioxide removal (CDR) is necessary alongside rapid emission reductions. Some of the most discussed CDR options are land-based, e.g. reforestation, changes in forest management, or cultivating bioenergy crops combined with carbon capture and storage (BECCS). Many previous studies assessed the eligibility of land-based mitigation options solely based on their biophysical capability to remove CO2 from the atmosphere. However, implementing land-based mitigation at large scales could also have detrimental side effects e.g. on biodiversity, water availability, food security, or local climate. Additionally, social constraints might limit the applicability of land-based mitigation efforts. STEPSEC aims to comprehensively assess the potential of land-based mitigation options globally and in Germany, taking into account biophysical, ecological, and social aspects, as well as potential synergies and trade-offs.
The main role of TUM in STEPSEC is to quantify the impacts of climate change, in particular more frequent and more extreme droughts, on the CDR potential and permanence of land-based mitigation options. This will be achieved by extending an existing plant hydraulics model in the LPJ-GUESS model, originally designed for the Amazon region, to temperate and boreal ecosystems. After evaluating the new model version for recent drought events in Europe, future simulations will be conducted for a range of climate projections and land-use scenarios. This allows us to identify regions most prone to climate change and explore potential adaptation measures.