Modelling planetary transition pathways to conservation agriculture under climate change

Agricultural production systems are increasingly constrained by interacting social-ecological pressures. While a growing world population and dietary shifts are increasing the demand for agricultural crop products, seven out of nine planetary boundaries are breached, with climate change at the forefront. On the production side, farmers face the challenge of implementing climate-resilient farming systems that can operate within planetary boundaries. Conservation agriculture, as part of sustainable and regenerative agriculture, is believed to potentially play a significant role in this development. However, this has not been sufficiently assessed at larger scales. Existing global modelling approaches have predominantly focused either on stylized biophysical potential assessments or macroeconomic optimization approaches. Both approaches often neglect the endogenous decision-making of individual land-use actors. Here, we introduce an integrated World–Earth modelling approach that couples farmers' socio-economic decision-making related to the adoption of farming practices with process-based terrestrial biosphere and, in particular, crop modelling. Using the recently bulit InSEEDS model embedded within the copan:LPJmL modelling framework, we investigate social-ecological co-evolutionary feedback mechanisms of land-use systems at the global scale. For this first large-scale application of InSEEDS, it is extended to include socio-economic and supra-regional communication feedbacks, alongside standardized procedures for providing empirical data for model validation. Modelled farmer agents can dynamically choose between tillage systems and decide on crop residue management and cover crop cultivation. We apply the model under a constant-climate scenario as well as SSP1-2.6 and SSP3-7.0 forcing scenarios. Our results indicate a strong influence of climate change on regional and temporal patterns in farmers' decision-making between conventional agriculture and conservation agriculture, taking into account socio-economic as well as socio-cultural factors. This highlights the importance of integrated modelling approaches for understanding co-evolutionary challenges and opportunities under climate change.