It remains a continuing challenge for companies worldwide to reliably assess the greenhouse gas emissions incurred in connection with their operations. Here we argue that financial accounting offers an architectural template for corporate carbon accounting systems consistent with current reporting frameworks for carbon emissions. The resulting CO2-statements yield a measure of a company’s current corporate carbon footprint, while stock variables on the CO2-balance sheet convey summary information about an entity’s past emissions performance and any recent changes therein. All accounting metrics emerge from a single ledger based on a transactional system of double-entry bookkeeping. Taken together, CO2-statements enable a unified, comprehensive, and temporally consistent assessment of the direct and indirect emissions of a business entity and its sales products. The similarities to existing financial accounting systems are bound to facilitate the adoption of such statements from both an enterprise software and an assurance perspective.