MEDALUS-R: a revised framework for large-scale spatiotemporal assessment of desertification susceptibility

Desertification remains a persistent environmental challenge in Europe with direct implications for the EU’s 2030 sustainability objectives, driven by interacting climatic, biophysical, and human factors. Most existing assessment frameworks, however, rely on static representations, predefined indicator thresholds, or lack an explicit treatment of temporal dynamics and policy-related dimensions. This study introduces MEDALUS-R, a revised, data-driven framework for the spatiotemporal assessment of climate-conditioned desertification susceptibility at the continental scale. MEDALUS-R conceptualizes susceptibility as a continuous spatial property emerging from the interaction of climatic stress, intrinsic land sensitivity, human pressure, and mitigation potential. Using harmonized multi-decadal datasets, objective indicator weighting, and unsupervised parameter optimization, desertification susceptibility is assessed for 37 European countries at 1-km resolution across three consecutive decades spanning 1996–2025. Results indicate that desertification susceptibility across Europe is spatially structured and evolves primarily through gradual intensification within established susceptibility regimes, with higher susceptibility and stronger intensification concentrated in Mediterranean and climatic transition zones. Climatic stress exhibits the strongest spatial association with long-term susceptibility increases, while mitigation-related conditions partially moderate intensification patterns and intrinsic land properties condition regional variability. Sensitivity analysis reveals coherent spatial patterns alongside increasing uncertainty under intensifying conditions, reflecting heightened system responsiveness rather than reduced model robustness. By extending MEDALUS to a multi-temporal, climate-conditioned framework and explicitly incorporating mitigation- and policy-relevant components, MEDALUS-R provides a transparent and adaptable basis for continental-scale monitoring and comparative assessment of desertification susceptibility, supporting soil protection and land degradation neutrality strategies in Europe.