Climatic Change the CO2 and CH4 contributions of major carbon producers, (3) full historical forcing minus all historical fossil fuel aerosols, and (4) full historical forcing minus all historical fossil fuel aerosols minus the CO2 and CH4 contributions of major carbon producers. The results of these simulations with the full range of sensitivity tests are in the ESM. 3 Global influence of emissions traced to major carbon producers 3.1 Atmospheric CO2 Atmospheric CO2 rose by ∼99 ppm from 1880 (289.8 ppm) to 2010 (388.4 ppm) (IPCC 2013). The model simulations with the best estimate parameters and full historical forcing yield an increase of ∼103 ppm over the same historical period (Fig. 1). Low thermal and carbon parameters with full historical forcing give the lowest ppm rise, and the high thermal and carbon parameters with full historical forcing minus all historical fossil fuel aerosols give the highest ppm rise (ESM). Removing the annual emissions traced to 90 major carbon producers from the best estimate full historical forcing case shows that the combustion of their products from the historical period led to a 58.8 (±3) ppm increase in atmospheric CO2 or 57.0 (±2.9)% of the total increased atmospheric CO2 over this period (ESM). This is predominantly (around three-quarters) due to major carbon producer-traced emissions of recent origin. Combustion of their products between 1980 and 2010 led to a 43.8 (±1.3) ppm increase, 42.5 (±1.3)% of total atmospheric CO2 increase between 1880 and 2010. For each forcing case, the contribution of major carbon producer-traced emissions to atmospheric CO2 is nearly evenly divided between the investor-owned companies, majority state-owned companies, and current or former centrally planned state industries (ESM). Along with atmospheric CO2, atmospheric CH4 changes were determined and incorporated into model calculations for radiative forcing, GMST, and GSL (Fig. 1 and ESM). To explore the potential climate responsibilities of non-state actors, it is of particular interest to understand the contribution of emissions traced to major carbon producers that are fully or partially investor-owned. Consider, for example, the contributions of emissions traced to the top 20 investor and majority state-owned companies to the increase in atmospheric CO2 (Fig. 2). Emissions traced to the top 20 investor and majority state-owned companies from 1880 to 2010 contributed ∼27.2 (±1.4)% of increase in atmospheric CO2 over the historical period, using best estimate parameters and full historical forcing (Fig. 2a). Combustion of products from the top 20 companies from 1980 to 2010 contributed 19.6 (±0.6)% of the historical rise in atmospheric CO2 (Fig. 2b). 3.2 Global mean surface temperature The IPCC AR5 reports a GMST increase from 1880 to 2012 of 0.85 (±0.2) °C (IPCC 2013). The model simulation for best estimate parameters with full historical forcing yields a GMST increase of ∼0.8 °C from 1880 to 2010 (ESM). The historical radiative forcing and GMST trend (ESM) demonstrate the competing influence of carbon emissions and intermittent volcanic eruptions (Robock 2000) or varying levels of historical fossil fuel aerosols (Shindell and Faluvegi 2010). Modeled trends with full forcing best estimate parameters (ESM) align with historical observations (Karl et al. 2015). As expected, removing the contribution of all historical fossil fuel aerosols for best estimate parameters yields a greater GMST modeled increase (∼0.97 °C) over this period.