Historic GHG emissions from human activity were assessed in both AR6 WGI and WGIII. Chapter 5 of WGI assessed 141CO2and CH4emissions in the context of the carbon cycle (Canadellet al., 2021). Chapter 2 of WGIII, published one 142year later (Dhakal et al., 2022), assessed the sectoral sources of emissions and gave the most up-to-date understanding 143of the current level of emissions. This section bases its methods and data on those employed in this WGIII chapter