Modeling the effect of land-based mitigation technologies on the carbon cycle and climate
Authors: Wimmer Florian , Tourigny Etienne , Martinez Cano Isabel , Stuch Benjamin , Schaldach Rüdiger 
Published: February 2023

The H2020 research project LANDMARC1 (Land Use Based Mitigation for Resilient Climate Pathways) will enhance understanding of the realistic potential of land-based negative emission solutions in agriculture, forestry, and other land use sectors. An important component of LANDMARC is modeling the effects of land-based mitigation technologies (LMT) on carbon fluxes and climate on the global scale.We will present the development of a coupled modeling system consisting of the EC-Earth3-CC Earth System Model (ESM) and the LandSHIFT-G land use model. In this model system, LandSHIFT-G models sequences of land-use maps on a spatial resolution of 5 arc-minutes by integrating assumptions on the future development of the agricultural sector (e.g. crop/livestock production, changes in average crop yields) and assumptions on the implementation of a selection of LMTs as specified in global or regional scaling scenarios. Based on these land-use/land-cover changes (LULCC), EC-Earth3-CC simulates potential effects on vegetation (both natural and managed) and atmospheric CO2 concentrations and climate variables on a spatial resolution of approximately 70 km. Changes in potential crop yields due to climate change are fed back to the land-use model, potentially affecting subsequent land-use patterns. Carbon fluxes between the atmosphere, vegetation, and soils as well as crop yields are modeled by the dynamic vegetation model LPJ-GUESS, which is a component of EC-Earth3-CC. Hence, the system addresses three feedback loops between land-use, vegetation and climate. Land-use change is impacted by crop yields and pasture productivity. Carbon fluxes as well as crop yields and pasture productivity are impacted by land-use change and climate while climate is influenced by changes in atmospheric CO2 and land surface properties.In the first version of the model system, it is foreseen to cover six different LMTs building on the capabilities of the models that are coupled. The set consists of (i) enhancement of carbon in vegetation and soils by afforestation, increasing soil carbon by (ii) no/reduced tillage agriculture and (iii) organic farming, combination of fossil fuel substitution and medium to long-term storage of carbon by (iv) BECCS (bio-energy and carbon capture and storage) and (v) application of biochar on cropland, as well as (vi) avoiding deforestation by&#160; enhanced cropland irrigation.In the current implementation, a simulation is done with a simplified modeling system, in which LandSHIFT-G is only coupled to LPJ-GUESS which is driven by atmospheric forcings from a previous EC-Earth3-CC model run, thus neglecting the dynamic effects under which the carbon cycle and land cover change impact the climate. As a proof of concept, we will present results of preliminary experiments simulating the effect of selected LMTs, e.g. afforestation, on the total carbon storage on land.&#160;1 The LANDMARC project has received funding from the European Union&#8217;s Horizon 2020 Research and Innovation Programme under grant agreement No 869367.