As the world enters a second year of the Covid-19 pandemic, the annual Global Energy Review assesses the direction energy demand and carbon dioxide emissions are taking in 2021. The latest statistical data and real-time analysis confirm our initial estimates for 2020 energy demand and CO2 emissions while providing insights into how economic activity and energy use are rebounding in countries around the world – and what this means for global emissions. The report explores whether the rebound in activity risks pushing CO2 emissions to a new high and to what degree new policies targeting a sustainable recovery are able to curb a rebound in emissions. The pace of global vaccine rollouts, the possible emergence of new variants of the Covid-19 virus, and the size and effectiveness of economic stimulus measures all represent major uncertainties for the outlook. This analysis therefore not only charts a possible path for energy use and CO2 emissions in 2021 but also highlights the many factors that could lead to differing outcomes.