Nowadays, companies are major contributors to greenhouse-gas emissions, and there is a pressing need to reduce the environmental impact of organizational processes. This work advances a systemic approach that helps organizations understand, and ultimately improve, their environmental footprint. The approach starts from a standard business process and expands it into a sustainability-aware process by explicitly representing the resources used and the activities that differ in their environmental impact. I formalize a method for multi-level impact estimation, with a particular focus on allocation strategies required when shared resources are involved and must be apportioned across processes or organizational units. Finally, I enhance the implementation of a tool that operationalizes the proposed approach by introducing a database to persist data and analyses, and by outlining an experimental plan to assess the tool in practice—aiming to deliver a solution that is genuinely useful for companies..