Global Photovoltaic Cool Island Effect Modulated by Dual Pathways of Evapotranspiration Suppression and Photovoltaic Conversion

As global photovoltaic (PV) deployment accelerates, PV systems, as a new land-atmosphere interface, significantly alter local thermal environments. However, the mechanisms driving the resulting surface cool island effect remain unclear. Utilizing multisource remote sensing data, this study quantifies global surface changes and cooling induced by PV installation through causal inference. Results show that PV installation leads to an 8.4% reduction in vegetation cover (-0.043) and a 4.82% decrease in surface albedo. Surface temperature decreases significantly, by 0.17 °C in daytime LST and 0.05 °C at night. Grassland and cropland cooling show significant seasonal variation, stronger in winter and weaker in summer; conversely, bare land maintains a stable cooling effect year-round. Causal inference reveals that the cool island effect is driven by two pathways: energy retention from reduced evapotranspiration and energy removal through photovoltaic conversion. In summer, the PV energy removal pathway is suppressed, while the stronger evapotranspiration pathway further weakens the cool island effect in photovoltaic areas relative to natural backgrounds; the opposite occurs in winter. These pathways, modulated by vegetation and climate, explain seasonal variations in the cool island effect. This study highlights the impacts of PV installation on surface energy balance, supporting synergies in carbon reduction, cooling, and ecological sustainability.