What is the difference between an LCA and a product carbon footprint, and which one does my buyer actually need?

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Senseible · Accepted Answer

A product carbon footprint measures one impact, climate change, in kg CO2e per unit. A full life cycle assessment covers many impacts, such as water use, acidification and eutrophication. If your buyer asks for a carbon footprint, PCF or Scope 3 data, a PCF is enough. An EPD or ecodesign request needs an LCA. ISO 14040 and ISO 14044 set out how to do an LCA. ISO 14067 defines a product carbon footprint as an LCA that looks at only one impact category, climate change. So a PCF uses the same life cycle method, with the same goal and scope, inventory and interpretation steps, but reports a single number in kg CO2e. Impacts: PCF covers greenhouse gases only. LCA covers a chosen set of impact categories, often ten or more. Standard: PCF follows ISO 14067 or the GHG Protocol Product Standard. LCA follows ISO 14040 and 14044, often with sector rules. Data needed: PCF needs energy, fuel, materials and transport with carbon factors. LCA needs the same inventory plus water, emissions to air, water and soil, and land use. Effort and cost: an LCA usually takes much longer and often needs specialist software and databases. Review: an LCA used for public comparative claims needs a critical review panel under ISO 14044. Request says carbon footprint, PCF, kg CO2e per unit, Scope 3 or supplier emissions: a PCF. Request says EPD, especially for construction products: an LCA to the product category rules, independently verified. Request says PEF, ecodesign or multiple environmental indicators: an LCA. Request is unclear: ask which indicators and which standard they will accept, and whether cradle-to-gate is enough. The inventory you build for a PCF, quantities of materials, energy and transport per unit, is the core of an LCA too. If a buyer later asks for more impacts, you extend the same data rather than starting again.