Carbon accounting is a relatively new research area. Whereas corporate carbon accounting is important for external stakeholders to receive a true and fair representation of an organization’s carbon footprint and efforts in emissions reduction, organizational management issues of carbon accounting are highly relevant with regard to decision making, performance improvement and what is reported. In contrast to the reporting, stakeholder and regulatory focus, company-internal issues of carbon accounting have so far rarely been investigated in depth. By analysing an in depth case study of an organization’s “convergence project” between two corporate accounting approaches, we raise questions about what should be considered an effective environmental accounting framework.