Climatic Change The UNFCCC process, focused on the allocation of climate responsibilities among emitting nations, is a well-established approach to addressing this challenging problem. But, society can attribute climate responsibilities in other ways as well, including to individuals and major emitting industries. Shareholder resolutions and calls for institutional divestment from the primary producers of coal, oil, and natural gas are now contributing to growing public, investor, and scholarly discourse on the particular climate responsibilities of major investorowned producers of fossil fuels (Lubber 2012; Oreskes 2013; Rockefeller Brothers Fund 2014). This is a reflection, in part, of growing attention to the actions that companies took and could have taken in light of the scientific evidence of climate change (Frumhoff et al. 2015). The tools of attribution science are being applied to characterize specific damages resulting from anthropogenic climate change (Mitchell et al. 2016). Policymakers in several jurisdictions are now considering whether fossil fuel producers might bear some responsibility for such climate damages potentially traceable to emissions from their products (van Renssen 2016). The present analysis provides a first step to inform such considerations by characterizing several global consequences linked to these emissions. One source of uncertainty in characterizing the contribution of emissions to global climate change is the equilibrium climate sensitivity (ECS) and transient climate response (TCR) to an increase in atmospheric CO2 (IPCC 2013). Parameters were tested through their published range of values. The bestestimate parameters with full historical forcing yield results that most closely aligned with historical observations over recent decades. A secondary source of uncertainty is the short-term effects of fossil fuel aerosols. Typically, nations set the policies regarding aerosol emissions from fossil fuel combustion; hence the aerosols linked to a given product could vary under different regulations governing combustion. If policymakers decide to factor in aerosols traced back to carbon producers when considering their climate responsibilities, steps could then be taken to require reporting of production, processing, and combustion region to better estimate resulting aerosol emissions. Policy in this area should be cognizant, however, of the danger of providing corporations with an incentive to emit aerosols to offset the climate responsibilities implied by their products or Bprivate geoengineering.^ Over the long term, the legacy of long-lived heat-trapping emissions outlive the temporary offset from the associated short-lived aerosols from fossil fuel combustion, biomass burning, and other anthropogenic sources (Shindell and Faluvegi 2010; Solomon et al. 2010). With respect to the question of climate responsibility, a third source of uncertainty is the policy relevance of different time periods of historical carbon emissions. Researchers exploring the allocation of responsibilities among nations for greenhouse gas emissions typically consider cumulative emissions over the historical period since 1880, when GMST data are sufficiently abundant and biases in the early records are understood and can be corrected (Matthews et al. 2014; Karl et al. 2015). The attribution of climate responsibility among non-state actors such as investor-owned fossil fuel companies might also take account of the timing by which companies should have reasonably been expected to respond to evidence of the climate risks of their products by, for example, investing in low-carbon energy technologies, supporting climate policies and legislation, or communicating these risks with consumers and shareholders (Frumhoff et al. 2015). Strikingly, more than half of all emissions traced to carbon producers over the 1880–2010 period were produced since 1986, the period in which the climate risks of fossil fuel combustion were well established. Consistent with this, our results show that bounding consideration of cumulative emissions to recent decades (1980–2010) only modestly reduces