Enhancing climate mitigation: photovoltaic deployment as a complement to afforestation

Abstract Large-scale photovoltaic (PV) deployment and afforestation represent vital climate change mitigation strategies, yet the climate mitigation potential of PV deployment in regions where afforestation is constrained remains understudied. Using the Community Earth System Model (CESM2.1.3), we quantitatively assess the carbon reduction and surface temperature effects of large-scale PV deployment and afforestation across global potential afforestation areas. Our results reveal regional limitations of afforestation and demonstrate strong climate benefits from PV deployment in these constrained regions. Our results demonstrate that PV deployment in potential afforestation regions could reduce carbon emissions by 3.47 Gt C yr-1 while decreasing global surface temperatures by 0.08 °C, whereas afforestation yields a smaller carbon sink (0.075 Gt C yr-1) and induces slight global warming (+0.02 °C). In arid zones, where solar radiation is high and bare land is prevalent, PV deployment mitigate 2.24 Gt C yr-1 (114 Mha) and cools the surface by -0.26 °C, whereas afforestation induces warming of +0.16 °C due to albedo reduction. In boreal regions, PV deployment cools surfaces by -0.26 °C, whereas afforestation leads to a +0.21 °C warming. These results demonstrate that in regions where afforestation is limited by water scarcity or induces biophysical warming, PV deployment can provide effective climate mitigation through stable carbon reduction and surface cooling.