Defining freshwater as a natural resource: A framework linking water use to the area of protection natural resources.

PURPOSE: While many examples have shown unsustainable use of freshwater resources, existing LCIA methods for water use do not comprehensively address impacts to natural resources for future generations. This framework aims to (1) define freshwater resource as an item to protect within the Area of Protection (AoP) natural resources, (2) identify relevant impact pathways affecting freshwater resources, and (3) outline methodological choices for impact characterization model development. METHOD: Considering the current scope of the AoP natural resources, the complex nature of freshwater resources and its important dimensions to safeguard safe future supply, a definition of freshwater resource is proposed, including water quality aspects. In order to clearly define what is to be protected, the freshwater resource is put in perspective through the lens of the three main safeguard subjects defined by Dewulf et al. (2015). In addition, an extensive literature review identifies a wide range of possible impact pathways to freshwater resources, establishing the link between different inventory elementary flows (water consumption, emissions and land use) and their potential to cause long-term freshwater depletion or degradation. RESULTS AND DISCUSSION: Freshwater as a resource has a particular status in LCA resource assessment. First, it exists in the form of three types of resources: flow, fund, or stock. Then, in addition to being a resource for human economic activities (e.g. hydropower), it is above all a non-substitutable support for life that can be affected by both consumption (source function) and pollution (sink function). Therefore, both types of elementary flows (water consumption and emissions) should be linked to a damage indicator for freshwater as a resource. Land use is also identified as a potential stressor to freshwater resources by altering runoff, infiltration and erosion processes as well as evapotranspiration. It is suggested to use the concept of recovery period to operationalize this framework: when the recovery period lasts longer than a given period of time, impacts are considered to be irreversible and fall into the concern of freshwater resources protection (i.e. affecting future generations), while short-term impacts effect the AoP ecosystem quality and human health directly. It is shown that it is relevant to include this concept in the impact assessment stage in order to discriminate the long-term from the short-term impacts, as some dynamic fate models already do. CONCLUSION: This framework provides a solid basis for the consistent development of future LCIA methods for freshwater resources, thereby capturing the potential long-term impacts that could warn decision makers about potential safe water supply issues in the future.

Eutrophication and climate change impacts of a case study of New Zealand beef to the European market.

OBJECTIVE: Beef production in the Lake Taupo region of New Zealand (NZ) is regulated for nitrogen (N) leaching. The objectives of this study were to 1) evaluate the implications of nitrogen emission limitations on eutrophication and climate change impacts of NZ beef through its life cycle to a European market and uniquely link it to 2) estimation of the reduction in these impacts that can be funded by the consumer's willingness to pay (WTP) a premium for a low environmental-impact product. METHOD: The cradle-to-market Life Cycle Assessment (LCA) of NZ beef on the European market included beef production on farms, meat processing, packaging and transport stages. Various beef production systems in the Lake Taupo region were modelled: farm systems with and without regulated N leaching limits in place (using N fertiliser inputs of 0 and 100 kg N/ha/year respectively) using suckler beef or beef derived from surplus calves from a dairy farm. The FARMAX model was used to model farm productivity and profitability under these various scenarios, whereas the OVERSEER® model was used to model field/farm emissions (N, phosphorus (P)) and the NZ greenhouse gas (GHG) Inventory model was used to estimate total GHG emissions. Eutrophication and climate change impacts of NZ beef to the European market were calculated using recent regionalised LCA indicators. We estimated freshwater and marine eutrophication impacts of European beef using published N emissions to water and air. We estimated the European consumer's WTP for beef with positive environmental attributes based on a meta-regression analysis based on 21 published studies and compared farmer's profit for the farm system scenarios. RESULTS: When using common P-driven eutrophication indicators, the farms using 100 kg fertiliser-N/ha/year appeared to have a lower freshwater eutrophication impact than farms using no N fertiliser, which is in contradiction with the local freshwater policy for N regulations. When the contribution of both N and P were accounted for, the farms using no N fertiliser had the lowest estimated impact. Comparison with published environmental footprint of beef from Europe showed lower climate change and eutrophication impacts for NZ beef, thus showing potential positive environmental attributes for NZ beef. The European consumer's WTP (32% price premium) for such a beef product with low environmental impacts could offset the cost to farmers for implementing the reduction of N emissions. CONCLUSIONS: Bridging the gap between local freshwater policy and LCA indicators starts by considering both P and N emissions and impacts. Combining an environmental LCA with an economic analysis revealed that the consumer willingness to pay could compensate for the environmental cost of protecting the lake that currently only the farmers are bearing.

A comprehensive planetary boundary-based method for the nitrogen cycle in life cycle assessment: Development and application to a tomato production case study.

Existing methods that apply the planetary boundary for the nitrogen cycle in life cycle assessment are spatially generic and use an indicator with limited environmental relevance. Here, we develop a spatially resolved method that can quantify the impact of nitrogen emissions to air, soil, freshwater or coastal water on "safe operating space" (SOS) for natural soil, freshwater and coastal water. The method can be used to identify potential "planetary boundary hotspots" in the life cycle of products and to inform appropriate interventions. The method is based on a coupling of existing environmental models and the identification of threshold and reference values in natural soil, freshwater and coastal water. The method is demonstrated for a case study on nitrogen emissions from open-field tomato production in 27 farming areas based on data for 199 farms in the year 2014. Nitrogen emissions were modelled from farm-level data on fertilizer application, fuel consumption and climate- and soil conditions. Two sharing principles, "status quo" and "gross value added", were tested for the assignment of SOS to 1 t of tomatoes. The coupling of models and identification of threshold and reference values resulted in spatially resolved characterization factors applicable to any nitrogen emission and estimations of SOS for each environmental compartment. In the case study, tomato production was found to range from not transgressing to transgressing its assigned SOS in each of the 27 farming areas, depending on the receiving compartment and sharing principle. A high nitrogen use efficiency scenario had the potential to reverse transgressions of assigned SOS for up to three farming locations. Despite of several sources of uncertainty, the developed method may be used in decision-support by stakeholders, ranging from individual producers to global governance institutions. To avoid sub-optimization, it should be applied with methods covering the other planetary boundaries.

Water scarcity footprint of dairy milk production in New Zealand - A comparison of methods and spatio-temporal resolution.

Water scarcity footprinting now has a consensual life cycle impact assessment indicator recommended by the UNEP/SETAC Life Cycle Initiative called AWaRe. It was used in this study to calculate the water scarcity footprint of New Zealand (NZ) milk produced in two contrasting regions; "non-irrigated moderate rainfall" (Waikato) and "irrigated low rainfall" (Canterbury). Two different spatial and temporal resolutions for the inventory flows and characterisation factors (CFs) were tested and compared: country and annual vs. regional and monthly resolution. An inventory of all the consumed water flows was carried out from cradle to farm-gate, i.e. from the production of dairy farm inputs to the milk and meat leaving the dairy farm, including all water uses on-farm such as irrigation water, cow drinking water and cleaning water. The results clearly showed the potential overestimation of a water scarcity footprint when using aggregated CFs. Impacts decreased by 74% (Waikato) and 33% (Canterbury) when regional and monthly CFs were used instead of country and annual CFs. The water scarcity footprint calculated at the regional and monthly resolution was 22 Lworld eq/kg FPCM (Fat Protein Corrected Milk) for Waikato milk, and 1118 Lworld eq/kg FPCM for Canterbury milk. The contribution of background processes dominated for milk from non-irrigated pasture, but was negligible for milk from irrigated pasture, where irrigation dominated the impacts. Results were also compared with the previously widely-used Pfister method (Pfister et al., 2009) and showed very similar ranking in terms of contribution analysis. An endpoint indicator was evaluated and showed damages to human health of 7.66 × 10-5 DALY/kg FPCM for Waikato and 2.05 × 10-3 DALY/kg FPCM for Canterbury, but the relevance of this indicator for food production needs reviewing. To conclude, this study highlighted the importance of using high-resolution CFs rather than aggregated CFs.