CO ₂ emissions are of global concern because of climate change. China has become the largest CO ₂ emitter in the world and presently accounts for 30% of global emissions. Here, we analyze the major drivers of energy-related CO ₂ emissions in China from 1978 when the reform and opening-up policy was launched. We find that 1) there has been a 6-fold increase in energy-related CO ₂ emissions, which was driven primarily (176%) by economic growth followed by population growth (16%), while the effects of energy intensity (−79%) and carbon intensity (−13%) slowed the growth of carbon emissions over most of this period; 2) energy-related CO ₂ emissions are positively related to per capita gross domestic product (GDP), population growth rate, carbon intensity, and energy intensity; and 3) a portfolio of command-and-control policies affecting the drivers has altered the total emission trend. However, given the major role of China in global climate change mitigation, significant future reductions in China’s CO ₂ emissions will require transformation toward low-carbon energy systems.