Since the Kyoto Protocol was established in 1997, a number of countries have made policies and plans to establish goals for greenhouse gas (GHG) emission reduction by the target year of 2020. Because GHG emissions in the construction industry account for a significant portion (approximately 12.9%) of the total GHG emissions, strategies for reducing GHG emission have been widely explored in the construction sector. However, these attempts have been focused mostly on individual or small construction projects. A systematic approach for managing and monitoring GHG emission factors at the macro level of collective projects must reflect the nature of large-scale construction projects. This paper proposes a conceptual framework for a carbon management system (CMS) for large-scale construction projects, focusing on carbon emissions. A preliminary analysis was conducted via literature review and survey. Based upon the results, a GT-PCM (Green Technology-Plan, Control, and Monitor) framework is proposed for implementing GHG emission policy for the duration of a mega-sized project at the program level that constitutes a complex set of interrelated and connected sub-projects. A case study application to a large-scale urban development project was conducted not only to assess the applicability of the framework but also to identify future research needs to overcome limitations of the current framework.