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Whole life carbon emissions (WLC) are the entire amount of carbon produced by any particular built asset, from a house to an office block to an airport. If we truly want to achieve net zero cities, we need to understand the WLC implications of the designs we develop and the buildings we fund and use.
Getting it done
Every aspect of construction produces a potential carbon impact, so identifying where the emissions enter the life cycle of construction is the only way to make a credible carbon accounting within the built environment. WLC emissions result from the form, materials, construction methods, and operation of a building over its entire life, including its demolition and disposal. To understand a project’s total impact, we have to assess both the anticipated operational and embodied emissions over the whole life of the asset. To reduce lifetime emissions, WLC assessment needs to be part of a building or asset’s initial design specification so that clients and investors and designers can agree on the most sustainable solution. Only then can an entire project achieve Net Zero Operational Carbon – where CO2 emissions are reduced to a level consistent with reaching net zero on the 1.5oC pathway.
Embodied vs operational emissions
Whole life carbon emissions need to be understood in two dimensions: embodied and operational. Embodied emissions are comprised by the materials and energy used to produce and assemble them. These are easier to analyse and score than the just-as-important operational emissions. These are produced by the building’s day to day occupancy and use. For example, certain choices of façade mean a building in a particular climate can be passively heated and cooled, radically lowering energy costs throughout its life. If this isn’t prioritised, perhaps a client selects a design where the glazing absorbs a large amount of the sun’s rays every day, air conditioning will need to be used to a far greater extent. There are a myriad of operational emission considerations, driven by client goals, design specification, the buildings materials, location and purpose. They all need to feed into a rigorous whole life carbon assessment that can shape the most sustainable solution.
Learn more about Zero - Arup's new whole life carbon assessment tool
As regulators, investors, and insurers begin to evaluate new and existing buildings more closely, WLC assessment is rising in prominence as the means to assess an asset’s climate impact. In the longer term, a circular economy approach to managing WLC for building lifespans may well be a more efficient and reliable means of achieving net zero.
Once construction, transport and disassembly can be carried out with renewable energy, and with the use of predominantly recycled materials, the promise of net zero buildings can be realised. Until this is achieved, we must reduce WLC emissions progressively to achieve the target of net zero by 2030 and avert the impending disaster of climate change.