Pergularia daemia (Forssk.) Chiov. exhibits dual ecological and socio-economic roles, functioning both as a valued ethnomedicinal plant and an invasive weed across tropical and subtropical drylands. Despite its wide adaptability, the species climatic niche dynamics and future distribution under climate change remain poorly quantified. This study provides the first global assessment of the climatic suitability, key environmental drivers, and potential future distribution of P. daemia under multiple emission scenarios. A total of 710 spatially thinned occurrence records were modelled using an Ensemble Species Distribution Modelling (ESDM) framework incorporating eight algorithms (GLM, GAM, MARS, ANN, CTA, SVM, MaxEnt, and Random Forest). Predictors included harmonized bioclimatic and non-bioclimatic variables for baseline modelling, while future projections (2050 and 2070 under RCP 4.5 and RCP 8.5) were generated using the BCCCSM2-MR GCM. Niche dynamics were further evaluated using ellipsoid niche hypervolume (ENH) analysis. Current estimates highlight high suitability in semi-arid regions of Sub-Saharan Africa and peninsular India, strongly influenced by annual precipitation (Bio12), precipitation seasonality (Bio15), and isothermality (BIO3). Future projections indicate a temporary increase in climatically suitable area by 2050; however, this potential expansion may not translate into realized habitat occupancy. By 2070, suitability declines markedly, with pronounced habitat fragmentation and a substantial rise in low-suitability zones, particularly under highemission scenarios. Peripheral and marginal suitability corridors critical for dispersal connectivity show >90% contraction. ENH analyses reveal initial niche expansion under moderate warming, followed by niche contraction and displacement under stronger warming trajectories.