Simulating the economic and health impacts of synergistic emission reduction from accelerated energy transition in Guangdong-Hong Kong-Macao Greater Bay Area between 2020 and 2050

The pace of energy transition plays a pivotal role in realizing cleaner air and combating climate change in the forthcoming decades. In this study, using a system-based model, we assessed and simulated the climatic, economic and health impacts of synergistic reduction of CO2 and primary air pollutants (i.e., NOX, SO2, PM2.5, and PM10) under different paths of accelerated energy transition in Guangdong-Hong Kong-Macao Greater Bay Area (GBA) of China over 2017–2050. We show that fast decarbonization of the energy system targeting China's carbon peaking and carbon neutrality goal may lead to 90% (270 Mt) more reduction of GBA's CO2 emissions between 2020 and 2050, compared to Business-As-Usual scenario, meanwhile all primary pollutants would be reduced by 70%–80%, much higher than the scenarios prioritizing energy safety (higher reliance on all fossil fuels) or cleaner energy use (higher demand on natural gas). While the synergistic emission reduction effect of SO2, PM2.5 and PM10 may decrease after 2035, the decarbonization-oriented energy transition could still be an efficient tool for simultaneously reducing NOX and CO2 by 2050. A reduction of 1 t CO2 would be accompanied by reduction of 1.7–1.8 kg NOX in 2050, 78–132% higher than that in 2030. Fast-decarbonizing energy transition may result in 20% reduction of GBA's GDP growth rate after 2030, although 16–49% of the economic loss could be offset by the abated pollution-related health expenditures and premature deaths. This highlights the need for a more balanced strategy to accelerate energy transition, achieving fast decarbonization while also reduing the detrimental economic and health impacts of air pollutants.