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Interview Details

Interview with Sebastien Humbert

  • LCA expert and Convener of the ISO Working Group ISO 14046 standard, Quantis
  • Dated: Wednesday, August 13th 2014
  • EWP: Can you explain to me, in the simplest of terms what water footprinting is? For example, a company wants to go for water footpring, they have to know how much and from where they are getting the water? Would they also need to know from where and how much water is used for their raw materials?

    Sebastien Humbert : Water footprinting allows water users to understand the impacts associated with the water they use or affect (polluted or degraded) in their production processes. The amount can be water withdrawal but more typically water consumed, subtracting water withdrawn from water discharged. It is important to note that not only site pollution from water discharge is taken into account, but air and soil pollution which could potentially impact water quality also needs to be considered.

    The Life Cycle Assessment approach, on which the new ISO 14046 standard is based, goes one step further in that water users need to look at their general supply chain in order to get an overview of how the product could be made more sustainable, in terms of water. This requires that the same calculation (i.e. water inventory and impact assessment) be repeated for all processes within the supply chain. This is an important step because, ultimately, companies or consumers do have an influence on the products that they source and thus whether their products are sources from sustainable suppliers or not.

    EWP: Water footprint assesses the water impact of products, processes and organization, how does the standard incorporate local water challenges into the standard (i.e. water stressed areas, possible eutrophication sensitive waterbodies, etc.)? And does it assess this local impact when a product is produced in several locations or when an organization has sites located around the globe? How is the impact from the raw materials added (if they are located in different drainage areas?)

    Sebastien Humbert : As scientists are still in the process of trying to agree on the best methodology for water stress, ISO decided that it was not conducive to mandate specific methodologies at the moment in order to given the scientific community greater opportunities to explore. The standard principles maintain that water users should make this assessment themselves, using the most up to date and innovative methodologies. Water users should demonstrate proof of how their water assessment was made and calculated.

    The new ISO/TR 14073, currently being drafted by the same ISO working group, will provide some guidance and examples of how these calculations could be performed. Eventually, ISO intends to give standard users some examples of possible methodologies to determine this impact and will look at recommendations from WULCA, an international group of experts developing water footprint methodologies for water consumption as well as from other bodies such as other international group of experts from UNEP-SETAC developing water footprint methodologies for water pollution.

    The overall benefit of Water Footprinting, as defined by ISO, rather than providing detailed information about water management at local level is to give water users general information about where the hot spots are in their (complex) supply chains. For water users with a straightforward supply chain, or a product produced on one site, Water Footprinting, as defined by ISO, may not provide extensive information. Rather, the exercise serves water users with especially complex supply chains or for water users exploring alternative supply chains. For example, a multinational may use Water Footprinting to identify where to prioritize limited time and resources to reduce its overall water footprint. Also, a company getting information about water related risks in supply chain activities in several areas of the world for investment purposes, water footprinting would help identify which option could be the most resilient.

    EWP: I understand that the Water Footprint Network participated in the development of the ISO standard - so if a company has calculated Water footprint according to the WFN, what is the relation to ISO, for example how would a company deal with the varying blue, green and grey water aspects as with WFN?

    Sebastien Humbert: WFN participated in the ISO working group WG 8, Water footprint, in order to provide its expertise and ensure alignment between the two initiatives. Companies that have already completed the WFN at the inventory level only will need to complete a bit more work in order to achieve compliance with the ISO standard, including adding the identifying local water stress to discriminate relative importance of “different” blue water. Although WFN at the moment includes this as a recommendation, reports show that the vast majority of those using WFN don’t delve into aspects of local water stress.  Also, ISO recommends to assess water pollution in a more comprehensive way that the traditional grey water footprint indicator of most WFN studies.

    Concerning blue, green and grey water aspects of water footprinting, studies showed that greenwater as the result of agricultural processes tended to constitute a large majority of total footprint. However, from ISO’s perspective green water does not necessarily result in an environmental impact and thus has not included this as a necessary component of the ISO at the impact level.

    EWP: The standard requires examples of water related impact categories-what would be an example of this? Water scarcity? Is there a method to calculate them?

    Sebastien Humbert: Again there are no defined methodologies for calculating water-related impact, but standard implementers are advised to use state of the art information available. A non-exhaustive list of some of the indicated categories would include for example: Water scarcity (i.e water consumed that would be in competition with other water users), Freshwater Ecotoxicity, Water eutrophication, Water acidification and Thermal pollution of rivers.

    For the sake of transparency, the ISO standard requires that each of them, if assessed or reported individually, should be used as a qualifier in the water footprint term, as for example “Water eutrophication footprint”, to be transparent in what as been assessed.

    DG Environment has collaborated with European Commissions Joint Research Centre to develop harmonized methodologies for the calculation of the environmental footprint of products and organizations. The Product (and Organizational) Environmental Footprint has compiled a specific list of impact categories that may also be used for users attempting to calculate their water related impacts.

  • Sebastien Humbert
  • LCA expert and Convener of the ISO Working Group ISO 14046 standard, Quantis
The newly released ISO 14046 specifies principles, requirements and guidelines related to the water footprint assessment of products, processes and organizations, based on life-cycle assessment.

- Sebastien Humbert
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