The aim of this case study was to explain how voluntary climate initiatives are communicated to employees, and the role of employee involvement as an antecedent for more strategic environmental sustainability work. More specifically, the project explored enabling factors for stakeholder involvement from a Corporate Social Responsibility (CSR) communication perspective. A flexible research design was structured through qualitative methods and an inductive approach. Semi-structured interviews and corporate sustainability documents from two knowledge-intensive IT businesses were analyzed to understand the internal CSR landscape related to voluntary climate initiatives, like carbon offsetting actions and reduce-reuse-recycle efforts. The theoretical framework used concepts from CSR communication, environmental marketing and stakeholder management. Case study findings indicate that voluntary carbon offsetting initiatives may have a notable impact on building a more distinct company-wide climate change agenda. Furthermore, the study confirmed that employees are important drivers in environmental initiatives and may act as informal sustainability ambassadors by supporting the organizational climate impact work internally (and later externally) – by building credibility from the inside-out.