OPERATIONAL VS. EMBODIED CARBON
Emissions from construction (embodied carbon) and operation make up the majority of a building’s life cycle emissions. Planning and designing greener buildings requires an understanding of the distinction between embodied and operational carbon. Embodied carbon is the carbon that is released in the production of all the materials used in the initial construction, the production of all the materials used in repairs or renovations over the life of the building, the transport of materials to the site and the construction, repair and renovation of the building. Operational carbon, on the other hand, is carbon that is released during the ongoing operation of the building. Lighting, power, heating, ventilation, air conditioning,
and other services like lifts and automatic doors are just a few examples of the sources of operational carbon emissions. There is growing concern that embodied impacts will become the primary source of global emissions. One result of efforts to reduce operational emissions is an increase in the proportion of embodied impacts over a building’s life cycle, which causes environmental pressures to shift from one stage to the next. Embodied emissions can account for more than 50% and as much as 74-100% of a building’s life cycle carbon emissions, depending on the structural types and functions of the building, the geographic location and climate, the construction methods used, and other factors. 4
“Owners and tenants are looking for greater visibility and influence over decarbonisation and waste reduction across their portfolios.”
CARBON WASHING IS THE NEW GREENWASHING
As embodied carbon has come under the spotlight, more suppliers and manufacturers have started to make dubious claims about how they are addressing the problem. Terms like “biodegradable”, “compostable” and “circular” have been replaced by phrases like “climate neutral”, “carbon negative”, “net-zero” and “offsetting”. When it comes to design and product specification, the issue with such terms is that they are often imprecise or inaccurate. See below for examples: • It is widely understood that “net-zero” means that there are no net contributions to atmospheric carbon across the entire life cycle of a product, but there is no officially agreed definition of net-zero. • “Low carbon” claims are often ambiguous. It could imply “lower carbon” than other similar goods or services, or customers could even interpret it to mean “carbon neutral” in some cases. • Claims of “carbon neutrality” are often based on inaccurate or unsubstantiated claims about life cycle carbon impacts. Manufacturers claiming that a product is carbon neutral may not necessarily be offering a better, longer lasting product.
• “Offsetting” is an often misused term. Reducing embodied carbon emissions is difficult, but carbon offsetting should be a last resort when no further manufacturing improvements can be made. Claims about “recycled content” should also be carefully scrutinised. Recycled content can be composed of two types of materials: post-consumer and post-industrial materials. Post-consumer material is made from goods that have been used by consumers but are then disposed of in recycling bins or solid waste streams. Post-industrial materials are leftover products from manufacturing processes or reclaimed waste that never made it to the consumer. When an existing product has served its purpose and is reused as the basis for a new product, less carbon dioxide is released into the atmosphere, and there is less pressure on our finite natural resources and raw materials. Post-industrial materials, by definition, did not reach the consumer, so when they are used to make a building product, it is merely adding new materials to the loop.
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