Here at Edge Environment, we have been grappling with how to best address temporary carbon storage in products, the inclusion of which can have a large bearing on the carbon footprint results for bio-based products (e.g. timber construction products).
With the recent launch of the Australasian EPD Programme, Environmental Product Declarations (EPDs) are gathering momentum, allowing the public communication of environmental impact results, and while not intended, an increase in direct product comparisons. In this instance the inclusion of temporary carbon storage in environmental impact results has the potential to create winners and losers when procurement decisions may be affected by a perceived climate benefit of one product over another.
Here is an attempt to decipher guidance from the most recent international standards, guidelines, and EPD Product Category Rules (PCRs) on how to address the issue.
First published in 2008, and then updated in 2011, the PAS 2050 offered guidance on carbon footprinting and greenhouse gas assessments – it allowed for carbon stored in products beyond the 100 year time horizon to be treated as carbon stored and included in the product footprint. Based on this guidance, carbon stored past 100 years (but not permanently) in bio-based products was effectively treated as equal to avoided fossil fuel emissions when calculating the carbon footprint of a product. While there is certainly a climate benefit with temporary storage of carbon in products (delayed emissions of CO2), the biogenic carbon cycle is complex and there is much uncertainty in the net climate impact of harvesting biomass. Some argue there is a delay of carbon uptake during biomass regrowth that may negate climate benefit of carbon storage in the product. Ultimately, aggregating impacts of biogenic carbon storage with fossil based carbon emissions should be avoided – we know that fossil emissions have more permanence and we can be much more certain of the climate impact.