...[M]ore than half of the global surface ocean acidification is attributable to the CO2 emissions traced to the extraction, refining and combustion of fossil fuels and manufacturing of cement from the 88 largest carbon producers... Of these 88 major carbon producers, 48 are investor-owned fossil fuel companies whose climate responsibilities are the focus of growing policy, legal and societal scrutiny. Emissions from majority state-owned and nationalized companies fall within the primary responsibilities of nation-states. Emissions traced to extraction, refining, marketing, and combustion of fossil fuels by these 48 investor-owned companies between 1965 and 2015 account for 15.5% of global ocean acidification... [Because] we are not able to quantify the interaction between all ocean changes stemming from anthropogenic carbon emissions, we likely underestimate the full loss and damage to marine biodiversity and communities stemming from emissions traced to major industrial carbon producers... [T]his paper provides a conservative basis for assessing the contribution of emissions traced to major carbon producers to marine loss and damage. The impacts of acidification on marine ecosystems and human communities dependent upon them can be amplified by ocean warming and other climate-change stressors; further modeling of these compound stressors could quantify the contribution of carbon producer-traced emissions to these impacts.