In 2021, U.S. energy-related carbon dioxide (CO2) emissions increased by 296 million metric tons (MMmt), or 6%, compared with 2020 levels. This increase followed a rise in economic activity and energy consumption once the initial economic impacts of the COVID-19 pandemic began to subside. Despite this increase in total emissions, in 2021, they were 274 MMmt (5%) lower than their pre-pandemic level in 2019 and 1,143 MMmt (19%) lower than their 2007 historical peak.