Global assessment of climatic responses to the ozone-vegetation interactions

Abstract. The coupling between surface ozone (O₃) and vegetation significantly influences regional to global climate. O₃ uptake by plant stomata inhibits photosynthetic rate and stomatal conductance, impacting evapotranspiration through land surface ecosystems. Using the climate-vegetation-chemistry coupled ModelE2-YIBs model, we assess the global climatic responses to O₃-vegetation interactions during boreal summer of 2010s (2005–2014). High O₃ pollution reduces stomatal conductance, resulting in the warmer and drier conditions worldwide. The most significant responses are found in the eastern U.S. and eastern China, where local latent heat flux decreases by -8.17 % and -9.48 %, respectively. Consequently, surface air temperature rises by +0.33 °C and +0.56 °C, and sensible heat flux rises by +16.54 % and +25.46 % in the two hotspot regions. The O₃-vegetation interaction also affects atmospheric pollutants. Surface O₃ concentrations increase by +1.26 ppbv in eastern China and +0.98 ppbv in eastern U.S. due to the O₃-induced inhibition of stomatal uptake. With reduced atmospheric stability following the warmer climate, increased cloudiness but decreased relative humidity jointly reduce aerosol optical depth (AOD) over eastern China. This study suggests that vegetation feedback should be considered for a more accurate assessment of climatic perturbations caused by tropospheric O₃.