The Carbon Majors Database contains greenhouse gas (GHG) emissions data on the largest company-related sources of all time. Attributing operational and product-related carbon dioxide and methane emissions to 100 fossil fuel producers (‘carbon majors’), the Database covers 52% of global industrial GHG emissions since the dawn of the industrial revolution (62% including nonextant companies). The novelty of the Database is that it presents a producer-side view of climate accountability and shows that significant contributions to anthropogenic climate change can be traced to a relatively small group of decisionmakers. It is also the most comprehensive database of corporate greenhouse gas emissions over time. The methodology described herein was used to complete a dataset of fossil fuel producer emissions covering the period from 1988: the year in which human-induced climate change was officially acknowledged by the international community through the establishment of the Intergovernmental Panel on Climate Change (IPCC). The dataset shows that half of global industrial greenhouse gases released since then can be traced to just 25 fossil fuel producing entities. Two of the coal producing states – China and Russia – are represented as nation state producers though it is a future objective to split these entities into constituent companies. In 2015, after the breaking up of these large state producers, half of global greenhouse gas emissions can be traced to 50 companies.