In the U.S. Energy Information Administration’s (EIA) Annual Energy Outlook 2021 (AEO2021), EIA projects that U.S. energy-related carbon dioxide (CO2) emissions will decline for most years through the mid-2030s but then begin to rise slightly from the mid-2030s through 2050. In the AEO2021 Reference case, EIA projects that, by 2050, U.S. energy-related CO2 emissions will be 5% higher than 2020 levels.