Existing LCA models may misrepresent embodied emissions LCAs comparing building materials can exaggerate the importance of one life-cycle phase (e.g. the embodied emissions of materials) by ignoring or discounting the contribution of other significant life-cycle emissions, such as operational stage emissions and the GHG impacts of other building systems. Used in isolation, these results can lead to decisions that are too narrow in scope and shift focus away from a more comprehensive picture of GHG emission reduction opportunities in buildings.
Building efficiency matters a great deal Despite tremendous progress on building efficiency, operational energy consumption remains the most important source of GHG emissions from a building over its life. Therefore, material choices need to be made on a building-by-building basis, driven not only by the need to reduce embodied GHG emissions, but by a holistic understanding of the role materials can play in enhancing the structure’s “whole life” environmental performance.
When combined factors such as forest regeneration rates, soil carbon loss and primary-to-new-growth-forest-conversion are all accounted for, the cradle-to-grave embodied emissions for a wood building could be 6% greater than for a concrete building.
When adding use phase emissions to the embodied emissions, the carbon impact of a wood building could be 1% greater than for a concrete building
International Institute for Sustainable Development • IISD.org SABMag - SUMMER 2019
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