Climate change–induced tropicalization of temperate ecosystems reshapes the global climatic context of zoonotic virus first detections

The tropicalization of temperate ecosystems driven by climate change is reshaping global patterns of zoonotic viral disease emergence. This study investigates the climatic drivers of emergences and evaluates how future climate change can alter their climatic suitability. Latitudinal analyses reveal a bimodal distribution of emergence sites, with a dominant peak near the equator and a secondary concentration in mid-latitudes. The highest emergence rates occur within the Intertropical Convergence Zone and decline toward the subtropics. Global hotspots are consistently concentrated in the core tropics. Climatic characterization shows that 80.5% of first detection sites occur in regions with mean annual temperatures above 18 °C, predominantly within tropical climate zones, especially tropical savannas. Ensemble learning identifies isothermality and the mean diurnal range as the strongest predictors of zoonotic virus emergence. Future projections under SSP2-4.5 and SSP3-7.0 scenarios indicate a progressive intensification and spatial reorganization of climatically suitable areas throughout the 21st century. High suitability remains centered in the tropics but is increasingly spreading into subtropical and temperate regions, especially under SSP3-7.0. By 2081–2100, many temperate areas see increased suitability, while parts of the tropical core stabilize or expand. Overall, the global risk landscape broadens and flattens, suggesting that future zoonotic viral emergence may become more spatially diffuse, with subtropical and temperate regions gaining importance alongside persistent tropical hotspots.