<p>Innovations in green technology: do they reduce carbon emissions? What factors in the process of green innovation affect changes in CO₂ emissions? To explore these issues, this study investigates the impact of green technology innovation on CO₂ emission changes by using a two-stage production-theoretical decomposition analysis (PDA) across 30 regions in China from 2014 to 2021. By dividing the innovation process into research and development (R&amp;D) and commercialization stages, we explore how efficiency at each stage influences CO2 emissions, identifying seven key drivers, including energy efficiency and green patent quality. The results show that while energy efficiency generally reduces emissions, the quality of green patents can sometimes lead to increased emissions. Moreover, regional disparities in innovation efficiency are evident, with Beijing, Jiangsu, Guangdong, and Qinghai demonstrating high overall efficiency, while regions such as Shanxi and Inner Mongolia show inefficiencies in R&amp;D, and Tianjin and Ningxia in commercialization. The study concludes that green technology innovation can reduce CO₂ emissions, but its effectiveness is contingent on both the stage of innovation and regional characteristics. Policymakers should focus on enhancing both R&amp;D and commercialization efficiency to fully realize the environmental benefits of green innovation.</p>