Understanding the LCA and ISO water footprint: A response to Hoekstra (2016) “A critique on the water-scarcity weighted water footprint in LCA”

Abstract

Water footprinting has emerged as an important approach to assess water use related effects from consumption of goods and services. Assessment methods are proposed by two different communities, the Water Footprint Network (WFN) and the Life Cycle Assessment (LCA) community. The proposed methods are broadly similar and encompass both the computation of water use and its impacts, but differ in communication of a water footprint result. In this paper, we explain the role and goal of LCA and ISO-compatible water footprinting and resolve the six issues raised by Hoekstra (2016) in "A critique on the water-scarcity weighted water footprint in LCA". By clarifying the concerns, we identify both the overlapping goals in the WFN and LCA water footprint assessments and discrepancies between them. The main differing perspective between the WFN and LCA-based approach seems to relate to the fact that LCA aims to account for environmental impacts, while the WFN aims to account for water productivity of global fresh water as a limited resource. We conclude that there is potential to use synergies in research for the two approaches and highlight the need for proper declaration of the methods applied.

The WULCA consensus characterization model for water scarcity footprints: assessing impacts of water consumption based on available water remaining (AWARE)

“…1). Additional discussion and justification on this assumption can be found in the following publications: the first one justifying the use of the available water minus environmental demand in the denominator (Hoekstra 2016) and the answer to this paper explaining the reason for including the human demand as well (Pfister et al 2017). When the value of the demand is equal to or larger than the availability (negative AMD), the characterization factor (CF) is set to be maximal since the equation would no longer be continuous nor hold the same meaning (Eq.…”

BOARD-INVITED REVIEW: Quantifying water use in ruminant production1

“…Even though refining the specific methods is expected to enhance the accuracy of estimates, using similar terminologies while presenting divergent or conflicting results may confer contradicting information on the same issue to the public. There were some attempts made by LCA and WFA communities to discuss and find complementarities between the 2 approaches, but those efforts have not yet led to unified methods (Boulay et al, 2013;Pfister and Ridoutt, 2014;Hoekstra, 2016;Pfister et al, 2017). Peters et al (2010) stated that calculating all water inputs to ruminant production in WFA may be useful to inform economic policy (e.g., determining if a nation is maximizing financial gain) whereas it may well be inappropriate to include green water if the focus is mitigating environmental burdens.…”

“…With LCA, possible environmental impacts can be assessed by either midpoint or endpoint indicators along the causeand-effect chain. Midpoint indicators refer to potential environmental impacts in the middle of the cause-andeffect chain (e.g., water scarcity), and endpoint indicators denote damage occurring at the end of a cause-andeffect chain, such as negative impact on human health or ecosystems as a result of water use (Pfister et al, 2017). Two companion studies conducted in Australia (Ridoutt et al, 2011(Ridoutt et al, , 2012 were among the first to analyze the water use of ruminant production systems in the standardized framework of LCA.…”

“…Furthermore, ISO 14046:2014(ISO, 2014 does not classify water into the blue, green, and gray categories that are commonly referred to in WFA studies. Although there is ongoing debate regarding the definitions of terms and other aspects associated with the methodologies to estimate water use (Hoekstra, 2016;Pfister et al, 2017), the ISO document serves as a valuable reference be- …”

BOARD-INVITED REVIEW: Quantifying water use in ruminant production

“…Green and blue water are given equal importance in WFA (Hoekstra et al, 2011;Hoekstra, 2015). Another important distinction between the WFA and LCA methods is that WFA treats water as a global issue whereas LCA considers water use as a local issue, assuming that there is no global fresh water shortage (Pfister, 2015;Hoekstra, 2016;Pfister et al, 2017). Most WFA and LCA studies also differ in their approach of calculating and communicating water use estimates.…”