The integration of sustainable thinking and performance within day-to-day business activities has become an important business need. Sustainable business requires information on the use, flows and destinies of energy, water, and materials including waste, along with monetary information on environment-related costs, earnings, and savings. Creating this holistic view of economic, social and environmental information is not a straightforward mission from an IT perspective, and implies tackling several challenges such as information granularity and overload, the different projections of the same factual information, and the heterogeneity of information systems. In this paper, we propose an entity-centric approach to Green Information Systems to assist organisations in forming a cohesive representation of the environmental impact of their business operations at both micro- and macrolevels. Initial results from a Small Medium-size Enterprise case study are discussed along with future research directions.