Using an extended Kaya decomposition, we identify the drivers of long-run CO2 emissions since 1800 for Denmark, France, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, the UK, the United States, Canada and Japan. By considering biomass and carbon-free energy sources along with fossil fuels, we are able to shed light on the effects of past and present energy transitions on CO2 emissions. We find that at low levels of income per capita, fuel switching from biomass to fossil fuels is the main contributing factor to emissions growth. As income levels increase, scale effects, especially income effects, become dominant. Technological change proves to be the main offsetting factor in the long run. Particularly in the last decades, technological change and fuel switching have become important contributors to the decrease in emissions in Europe. Our results also contrast the differentiated historical paths of CO2 emissions taken by these countries. •We study the long-run drivers of CO2 emissions in twelve developed economies.•We use novel data and apply an extended Kaya decomposition.•At low levels of income per capita, fuel switching is usually the main CO2 driver.•Scale effects are most important at higher levels of income and in the long-run.•Technological change is the main offsetting factor in the long-run.