A tool developed by the United Nations Environment Program (UNEP) for measuring energy use and carbon dioxide emissions in homes and offices is under consideration for standardization, a move that could lead to the creation of a uniform system for defining the climate impact of buildings. The Common Carbon Metric (CCM), developed by UNEP's Sustainable Buildings and Climate Initiative, is to be considered by the International Organization for Standardization (ISO), the world's largest developer and publisher of international standards, the UN agency said in a press release. The CCM is intended to create a uniform system for defining the climate impact of buildings through a consistent protocol, which can, in turn, help develop international baselines for use by architects, designers and the construction industry. The buildings are currently the single largest contributor to greenhouse gas emissions, with an estimated one third of global energy use taking place in offices and homes. Carbon dioxide emissions from buildings are set to rise from the 2004 level of 8.6 billion tons to 11.1 billion tons in 2020. “At UNEP we believe there is great potential for the building sector to contribute to significant reductions in greenhouse gas emissions,” said Sylvie Lemmet, the Director of UNEP's Division of Technology, Industry and Economics. “Development of the Common Carbon Metric and the ISO's decision to consider it as an international standard are important steps to remove the barriers to unlock this potential and provide a path to more energy efficiency in the building sector,” she added. Developing new standards for buildings can help governments plan more effectively towards achieving national targets on sustainability and reducing carbon emissions, according to UNEP. The CCM can also support the formulation of carbon credit schemes and other emission reduction mechanisms, the agency said. The tool is specifically designed to measure energy use when a building is operational. Given that the day-to-day use of buildings accounts for 80 percent to 90 percent of their total energy consumption, the CCM deals with the period in a building's lifespan where the greatest amount of emissions are produced. First launched during the UN Climate Change Conference in Copenhagen in 2009, the CCM measures both energy use and greenhouse gas emissions equivalent in buildings per metre squared or per occupant over the course of one year. It contains two approaches – a “top-down” model, which takes measurements from a collection of buildings, or a “bottom-up” model, which is applied to an individual building. BM/UN
