Assessment of the impact of “dual-carbon” goal on future changes in air pollution and climate in China

Abstract

<p indent=0mm>Carbon neutrality refers to achieving net-zero carbon dioxide emissions. Reducing CO₂ emissions is one of the major ways to achieve carbon neutrality and control air temperature rise. So far, numerous countries have pledged their goals of achieving carbon neutrality. In September 2020, China proposed a national dual-carbon goal and the associated timeline to achieve peak carbon and carbon neutrality. Therefore, how the proposal will lead to future changes in air quality and climate in China is of great interest. In the context of the dual-carbon goal, a series of emission reduction policies for different types of industries will be implemented to achieve CO₂ reductions. As a result, emissions of other pollutants will be reduced as well. Furthermore, future global climate change is also one of the main concerns. Most previous studies have focused on one single impacting factor without consideration of the dual-carbon goal. While carbon neutrality is an inevitable global trend, studies of its implication on air quality and climate change in China are still rare. Considering both regional emissions and global climate change will help predict future climate. Taking the dual-carbon goal into account will help adjust current emission reduction policies. In this study, we simulate the impacts of both regional emissions and global climate change in the future on China’s air quality and climate in the future under the dual-carbon goal scenario using a regional climate-ecology coupled model RegCM-Chem-YIBs, based on the Representative Concentration Pathway (RCP4.5) climate scenario and China’s 2030 emission data based on dynamics projection model (DPEC). Numerical simulations for present climate and present emissions, present climate and future emissions, and future climate and future emissions were performed. The comparison between the three sets of simulations provides how future regional emission reduction and global climate change will affect air pollution and climate in 2030. The study shows that, compared with 2015, the concentrations of fine particulate matter (PM_2.5), ozone (O₃), and carbon dioxide (CO₂) in China will decrease by approximately 36.8, <sc>19.8 μg m⁻³</sc> and <sc>1.9 ppm</sc> in 2030, respectively, under the combined effect of future regional emissions and global climate change. The temperature in the southern part of China will increase significantly, with an increase between 0.5 and <sc>1.5 K.</sc> Precipitation and clouds decrease by <sc>1−2 mm d⁻¹</sc> and <sc>3%−6%,</sc> respectively. The temperature in the northern part decreases slightly, generally below <sc>1 K.</sc> Precipitation and clouds increase by approximately 2 mm d⁻¹ and 6%, respectively. Overall, regional emission changes have a larger impact on PM_2.5, O₃ and CO₂ concentrations, which are the main influencing factors for future air quality changes, while global climate change has a greater impact on temperature, clouds and precipitation. Emission reduction policies under the dual-carbon target will significantly reduce air pollution, but may exacerbate warming at the surface because these policies will inevitably diminish the cooling effect of particulate matter. The mitigation of climate change will require GHG (greenhouse gas) and air pollution synergistic emission reduction policies and worldwide cooperation.