Effective carbon rates 2018 : pricing carbon emissions through taxes and emissions trading Decarbonisation keeps climate change in check and contributes to cleaner air and water. Countries can price CO2 emissions to decarbonise their economies and steer them along a carbon neutral growth path. Are countries using this tool to its full potential This report measures carbon pricing of CO2 emissions from energy use in 42 OECD and G20 countries covering 80% of world emissions. The analysis takes a comprehensive view of carbon prices including specific taxes on energy use carbon taxes and tradable emission permit prices. The ‘carbon pricing gap’ measures how much the 42 countries together as well as individually fall short of pricing emissions in line with levels needed for decarbonisation. On aggregate the ‘carbon pricing gap’ indicates how advanced the 42 countries are with the implementation of market based tools to decarbonise their economies. At the country level the gap can be seen as an indicator of long run competitiveness.