Climatic Change partition between the main carbon reservoirs—ocean, terrestrial, and atmosphere—a climate model can assess the fraction of CO2 remaining in the atmosphere while keeping track of the CH4 lifetime in the atmosphere and the resulting change in GMST. Study of Earth processes over millennia demonstrates that both the land ice volume and ocean volume respond to global mean surface temperature (IPCC 2013). Once we have changes in GMST, we use the model to calculate changes in GSL (Kopp et al. 2016). Two time periods were investigated for removing annual emissions traced to major carbon producers. The first, 1880–2010, represents the historical period with sufficient data available. The second, 1980–2010, follows the publication of the U.S. National Research Council report on carbon dioxide and climate and represents the period of growing awareness in the scientific, fossil energy industry, and policy communities of climate change risks associated with anthropogenic carbon emissions (NRC 1979; Frumhoff et al. 2015; Banerjee 2015). 2 Methods 2.1 Emissions traced to major industrial carbon producers Heede (2014) traces the annual CO2 and CH4 emissions (subtracting lubricants, petrochemicals, road oil, and other non-energy, non-combustion uses) between 1854 and 2010 to the 83 industrial producers of oil, natural gas, coal, and 7 cement manufacturers with annual production exceeding 8 MtC/year in 2006. Of these 90 major carbon producers, 50 are investor-owned, 31 majority state-owned, and nine are current or former centrally planned state industries. The activities of any carbon producer acquired over the course of the historical period are added to those of the acquiring corporation. Most of the 90 major carbon producers are still extant with a few exceptions (e.g., government-run industries in the former Soviet Union). Heede (2014) assumes that carbon was released to the atmosphere the same year of reported activity (i.e., fossil fuel extracted and marketed for combustion and manufactured clinker, a component of cement) (Gibbs et al. 2000; Energy Information Administration 2004). His conclusion that 63% of total industrial gigatonne CO2-equivalent (GtCO2e) carbon emissions can be traced to combustion of their products and direct company operational emissions used a hundred year global warming potential (GWP) of 21 for CH4 emissions (Eggleston et al. 2006). While cumulative carbon emissions is a reasonable proxy for total impact of CO2 emissions on GMST (Allen et al. 2009; Matthews et al. 2009; IPCC 2013), the correspondence is not exact on shorter timescales (Ricke and Caldeira 2014) and does not apply for CH4 (under any value of GWP). Hence, we extend the calculations in Heede (2014) using a simple climate model. 2.2 Climate model We use a global energy-balance coupled climate-carbon-cycle model (Millar et al. 2016) to assess the change in atmospheric CO2 and CH4 concentrations, radiative forcing, GMST, and GSL resulting from emissions traced to these 90 major carbon producers. CO2 concentrations would be directly relevant to impacts such as ocean acidification, while GMST correlates closely with many terrestrial and ocean impacts. We use the GMST to calculate GSL after Kopp et al. (2016). Climate models that rely on the underpinnings of reduced-complexity climate models and fully coupled earth-system models afford a number of advantages. Calibrated with historical observations and fully coupled global climate models, they can