Measuring Embodied Carbon

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“If you can’t measure it, you can’t improve it”. Peter Drucker’s quote is well known in the business world but it’s critically important for tracking embodied carbon. A fundamental piece of tracking embodied carbon is using a consistent way to measure embodied carbon: what phases of a building’s life you measure, what happens at the factory, how a material is shipped and installed, what repair and refurbishment are required, and what happens when the building is obsolete. This concept, commonly used in the consumer products and manufacturing sectors, is a method of environmental accounting called Life Cycle Assessment (LCA) and can be applied at either the product or building level. At the building level, it is referred to as a Whole Building Life Cycle Assessment (WBLCA) and considers the energy and inputs that go into a process and the environmental outputs as a result of that process.

Throughout pieces within the 2019 Stewardship Report, you will come across several references to LCA and Whole Building LCA. These reports and numbers are based on data sets of varying specificity. However, as specifiers request or regulators require procure specifiers regulators and procure building materials increasingly ask for this information material suppliers will be able to provide better information.

In some cases, the information is provided at an industry average level applicable to a specific country or region. In other cases, suppliers can provide embodied carbon data for their product for a single product from a single manufacturing site. Once we measure to this level of precision, specifiers can take into account factors such as more efficient manufacturing processes developed by suppliers, the specific fuel source, and products that consume large amounts of electricity in their manufacturing process—is it from fossil fuels or from renewable resources?

LCA data will always contain a level of uncertainty. However, it’s important to understand that even with uncertain data we can still take action to achieve meaningful reductions. Consistency and transparency are key to Life Cycle Assessment. LCA is performed per ISO standards and it is important to understand that when you compare two products that they both be functionally equivalent. Do they both perform the same function, or functions, and have the same expected life span? When you’re comparing options, one must ensure that they both will provide the same service for the same duration. Consider a roofing membrane for a building, if one lasts 15 years but the other has a 30-year expected life, a functionally equivalent comparison of the two must include double the material of the 15-year product as well as the energy expended to remove the first installation and any burdens associated with disposal.

At its simplest, Life Cycle Assessment is environmental accounting. You can’t have a budget if you don’t know how to count and you can’t manage embodied carbon if you don’t perform LCA.