When, in October 2010, the then UK government chief construction adviser Paul Morrell announced via the Innovation Growth Team that rules and methodologies for quantifying whole life carbon were a necessity on all projects, and stressed the need to collect and benchmark the carbon data, RICS took the decision to respond to the challenge in bite-size segments. In December 2012 it issued the Methodology to calculate embodied carbon of materials information paper, providing the industry with rules and guidance for undertaking the first part of the process-cradle-to-gate. However, limitations were recognised, one being was the paper was predominantly UK focused.
Life cycle carbon emissions
Some local authorities in the UK are now including mandatory cradle-to-gate embodied carbon assessments as part of the planning process (e.g. Brighton and Hove City Council). Meanwhile, other companies and organisations are quantifying and mitigating life cycle carbon emissions, among them the Environment Agency, the Highways Agency, Network Rail, Marks and Spencer and Crossrail. As a result, in March 2013, RICS established an international steering group aimed at expanding the scope of the methodology to include the life cycle carbon emissions, leading to the development of the Methodology to calculate embodied carbon in a building's construction life cycle guidance note, (see Figure 1).
Figure 1: Whole life carbon scopes
The established methodology can be applied to calculate life cycle carbon emissions of a building element. Most of the focus in the built environment to date has been on managing and reducing the energy consumption in buildings, such as lighting, heating, ventilation and air conditioning, through better design and management in use (regulated and unregulated loads). However, the emissions that result from the production, installation, maintenance and disposal of a building's materials remain largely unchecked. Because more buildings are constructed to higher energy efficiency standards, the proportion of the carbon emissions created is shifting from the operational emissions (gas and electricity and the like) to energy consumed during other life cycle stages of projects, such as in the manufacture of the materials, their transportation, the construction activities themselves and the eventual demolition and disposal. This therefore makes the new guide particularly important.
Containing a number of case studies and worked examples, the main aim of the guidance note is to provide a framework of practical guidance for surveyors on how to calculate embodied carbon emissions associated with their projects (see Figure 2).
Figure 2: A worked example shows how to calculate the life cycle carbon of a curtain wall system
Some good practice carbon reduction solutions have also been provided. This presents an opportunity for surveyors to offer this advice as part of the standard cost planning service, which in turn should help project teams and clients in decision-making. RICS expects building information modelling (BIM) to have a major impact in carbon quantification and mitigation in future. However, there will always be a need for early feasibility studies. This guidance note is not intended to replace any of the existing guides such as e.g. PAS 2050 and the Green House Gas Protocol but to make carbon calculation more accessible to the surveyor community. It is acknowledged that embodied carbon is a complex and relatively new area of research and therefore a number of assumptions have to be made that affect the accuracy of the outcome. But because the primary objective of measuring carbon emissions is to improve sustainability performance, it is felt that this guidance note will provide a valuable resource for the construction industry. Having completed a rigorous global consultation process, the guidance note is due to be published in March.