U.S. current and historical contributions to climate change and emissions 1850-2021

This figure contrasts the distribution of global population in 2021 (total = 7.86 billion), GHG emissions in 2021 (total = 51.6 GtCO₂e), cumulative CO₂ emissions (total = 2,200 GtCO₂) and historic contributions to warming (total = 1.61°C). Historic contributions to warming result from cumulative CO₂ emissions, but also estimated CH4, N₂O and F-gas emissions (cooling from aerosols is excluded, leading to a higher estimate of warming than currently observed). Note that due to missing data, these totals are not complete for all categories and exclude, for example, international transport. Current GHG and cumulative CO₂ emissions include net LULUCF CO₂ emissions (global bookkeeping approach) to align with historical emissions estimates (note that this leads to differences with section 2.3.1 where national inventories are used). Non-CO₂ gases are converted to CO₂ equivalents using global warming potentials with a 100-year time horizon from the IPCC AR6.