The world is currently grappling with a major global warming crisis that requires urgent remedial measures. This study uses the Feasible Generalized Least Squares (FGLS), Fixed Effect (FE), and panel threshold econometric techniques to examine the impact of export product diversification on CO2 emissions in China and across its regions, using province-level panel data from 2009 to 2017. We find that export product diversification and CO2 emissions are associated. Export product diversification has reduced CO2 emissions in China and across its regions. We also observed an inverted U-shaped relationship between CO2 emissions and export product diversification. Also, technical innovation (TI) and urbanization (Urban) significantly reduce CO2 emissions, but economic growth (EG) and energy consumption (EC) have statistically significant promoting effects on CO2 emissions in China. Except for economic growth, which is inversely related to CO2 emissions in the eastern region, the other controls have the same impact across the regions. Knowledge of the link between export product diversification (EPD) and CO2 emissions provides a theoretical foundation for economies to better leverage trade-related activities to achieve lower CO2 emission levels. Graphical abstract: [Figure not available: see fulltext.]