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

Can Italian wines outperform European benchmarks in environmental impact? An examination through the product environmental footprint method

Nowadays, there is a pressing demand for precise tools to quantify sustainability and assess the contributions of products and processes to sustainable development. This requirement extends to the wine industry as well. In 2013, the European Commission introduced the Product Environmental Footprint (PEF), providing a standardized methodology grounded in life cycle thinking for evaluating the environmental impacts of products across various industries. Despite its potential and the availability of specific guidelines for wine, the application of PEF remains unexplored in the sector. This study contributes to the knowledge by applying PEF to assess environmental impacts of Italian still and sparkling wines production, identifying variations from European benchmarks. Additionally, it aims to pinpoint pivotal hotspots and provide guidance for effective mitigation strategies. Average data from 27 wines certified as sustainable under Italian VIVA program, were collected and used to perform a life cycle assessment in accordance with PEF protocol. Results revealed that Italian still wines exhibited a greater environmental impact than the European reference value, while sparkling wines displayed a slightly more favourable environmental performance compared to the European average. Notably, specific impact categories remained consistent across different wines and countries, with climate change, resource utilization, land use, and particulate matter harmful for human health accounting for nearly 80 % of the overall environmental footprint. Hotspot analysis identified the plantation/destruction of vines, energy usage in the winery, and packaging as significant factors influencing the environmental footprint of Italian wines. Addressing these elements could enhance the environmental competitiveness of the Italian wine sector relative to its European counterparts. However, to validate these findings, further studies are necessary, both within Italy and in other European wine-producing regions. Such research initiatives will improve and strengthen PEF methodology, bolstering its adoption as the primary tool for environmental impact assessment of wine at the community level.

Advancing water footprint assessments: Combining the impacts of water pollution and scarcity

Several water footprint indicators have been developed to curb freshwater stress. Volumetric footprints support water allocation decisions and strive to increase water productivity in all sectors. In contrast, impact-oriented footprints are used to minimize the impacts of water use on human health, ecosystems, and freshwater resources. Efforts to combine both perspectives in a harmonized framework have been undertaken, but common challenges remain, such as pollution and ecosystems impacts modelling. To address these knowledge gaps, we build upon a water footprint assessment framework proposed at conceptual level to expand and operationalize relevant features. We propose two regionalized indicators, namely the water biodiversity footprint and the water resource footprint, that aggregate all impacts from toxic chemicals, nutrients, and water scarcity. The first impact indicator represents the impacts on freshwater ecosystems. The second one models the competition for freshwater resources and its consequences on freshwater availability. As part of the framework, we complement the two indicators with a sustainability assessment representing the levels above which ecological and human freshwater needs are no longer sustained. We test our approach assessing the sustainability of water use in the European Union in 2010. Water stress hampers 15 % of domestic, agricultural and industrial water demand, mainly due to irrigation and pesticide emissions in southern Europe. Moreover, damage to the freshwater ecosystems is widespread and mostly resulting from chemical emissions from industry. Approximately 5 % of the area is exceeding the regional sustainability limits for ecosystems and human water requirements altogether. Concerted efforts from all sectors are needed to reduce the impacts of emissions and water consumption under the sustainability limits. These advances are considered an important step toward the harmonization of volumetric and impact-oriented approaches to achieve consistent and holistic water footprinting as well as contributing to strengthen the policy relevance of water footprint assessments.

Water-Food-Carbon Nexus Related to the Producer-Consumer Link: A Review

Clarifying the water-food-carbon nexus is key to promoting the harmonious development of human society and environmental resources. The sustainable development of agricultural production systems is being challenged by water scarcity and climate change. Crop growth and irrigation consume large amounts of water, and greenhouse gases are generated due to processes such as fertilizer application and enteric fermentation. These environmental impacts accompany the agricultural production process and are thus embedded in the entire life cycle of diverse food items; in turn, consumers' food choices indirectly impact water consumption and greenhouse gas emissions. Reducing agricultural water consumption and greenhouse gas emissions during food production have become crucial issues in mitigating the projected water, climate, and food crises. From the consumer's perspective, diets vary regionally due to different natural conditions for food production and varying socioeconomic and income levels. This review delves into the interactions between diet and its potential environmental impacts, including water consumption and greenhouse gas emissions, in order to support further development of the water-food-carbon nexus.

Assessing the impact of water use in conventional and organic carrot production in Poland

As global water resources are decreasing and the demand for it is constantly increasing, the problem of proper water management is becoming more pressing. Poland is one of the largest producers of vegetables in Europe, including carrots, with significant exports. However its freshwater resources are relatively small. The paper presents the results of research on the water footprint (WF) life cycle assessment (LCA) in conventional and organic carrot production. The methodology of calculating WF was used in accordance with PN-EN ISO 14046. It was found, e.g., that WF for organic production of carrot (WF = 1.9 m³ ha⁻¹) is over five times lower, as compared to conventional production (WF = 10.4 m³ ha⁻¹). In the case of conventional production, the fertilization process (67.0–67.7%) has the greatest impact on the shaping of WF in the individual impact categories, i.e. Human Health, Ecosystem Quality and resources. In organic production, the WF-shaping factor is carrot harvesting (41.9–43.1%). The research can be used to develop pro-ecological carrot production technologies, as well as to shape sustainable development plans in agricultural areas. It can also be used to outline policy directions regarding foreign trade in water-consuming agricultural products.

Development of Method for Assessing Water Footprint Sustainability

Large scale production of water-intensive industrial products can intensify water scarcity, resulting in potential unsustainable water use at local and regional scales. This study proposes a methodological framework for assessing the WF sustainability of multiple interdependent products in a system, and one of China’s four major large modern coal chemical industry bases is used as a case study. A Mixed-Unit Input-Output (MUIO) model was applied to calculate the blue water footprint (WF) for 19 major coal-based energy and chemicals in the study area, based on which the WF sustainability of production of the products were assessed using different indicators. Technical coefficient matrix and direct water consumption vector of the products were constructed based a database that were built by field research in the study area. Accounting result indicates that the blue WF of the coal-based products range from 2.5 × 10−4 m3/kWh for coal-fired power to 55.25 m3/t for Polytetrahydrofuran. The sustainability assessment reveals that the blue WF of all products produced in the study area are sustainable at both product and regional levels, while over half of them have reached the advanced level. However, the blue WF of a few products with large production capacities has just crossed the sustainable thresholds, posing potential threat to the local environment. This paper concludes with a discussion on the choice of blue WF accounting approach, methods to promote WF sustainability of coal-based products, and suggestions for the WF management in general.

Animal board invited review: Animal source foods in healthy, sustainable, and ethical diets - An argument against drastic limitation of livestock in the food system

Animal source foods are evolutionarily appropriate foods for humans. It is therefore remarkable that they are now presented by some as unhealthy, unsustainable, and unethical, particularly in the urban West. The benefits of consuming them are nonetheless substantial, as they offer a wide spectrum of nutrients that are needed for cell and tissue development, function, and survival. They play a role in proper physical and cognitive development of infants, children, and adolescents, and help promote maintenance of physical function with ageing. While high-red meat consumption in the West is associated with several forms of chronic disease, these associations remain uncertain in other cultural contexts or when consumption is part of wholesome diets. Besides health concerns, there is also widespread anxiety about the environmental impacts of animal source foods. Although several production methods are detrimental (intensive cropping for feed, overgrazing, deforestation, water pollution, etc.) and require substantial mitigation, damaging impacts are not intrinsic to animal husbandry. When well-managed, livestock farming contributes to ecosystem management and soil health, while delivering high-quality foodstuffs through the upcycling of resources that are otherwise non-suitable for food production, making use of marginal land and inedible materials (forage, by-products, etc.), integrating livestock and crop farming where possible has the potential to benefit plant food production through enhanced nutrient recycling, while minimising external input needs such as fertilisers and pesticides. Moreover, the impacts on land use, water wastage, and greenhouse gas emissions are highly contextual, and their estimation is often erroneous due to a reductionist use of metrics. Similarly, whether animal husbandry is ethical or not depends on practical specificities, not on the fact that animals are involved. Such discussions also need to factor in that animal husbandry plays an important role in culture, societal well-being, food security, and the provision of livelihoods. We seize this opportunity to argue for less preconceived assumptions about alleged effects of animal source foods on the health of the planet and the humans and animals involved, for less top-down planning based on isolated metrics or (Western) technocratic perspectives, and for more holistic and circumstantial approaches to the food system.

Arjen Y. Hoekstra: A Water Management Researcher to Be Remembered

On 18 November 2019, the life of Arjen Y [...]

Effects of different Danish food consumption patterns on Water ScarcityFootprint

Food production and consumption have been recognized as a major source of environmental impacts. To ensure food security and a sustainable food system, dietary changes have been identified as one of the valuable strategies to reduce impacts on the environment while promoting human health. The vast majority of scientific literature has been focused on the effects of food consumption on climate change while neglecting to assess the degree of water scarcity impacts due to water consumption embodied in food. The research paper investigates the nexus between food consumption and impacts on water consumption adding important findings to a more recent growing body of studies estimating the water footprint (WF) of different dietary scenarios. This study uses the Water Footprint Network methodology and the AWARE (Available Water REmaining) characterization model to assess both the WF and the blue WSF (water scarcity footprint), respectively, of four Danish diets: standard, carnivore, vegetarian and vegan. In order to make them comparable, a total intake of 2000 kcal person^-1 day^-1 was set as energetic reference for all the diet scenarios considered. Using detailed trade and production data of agri-foods, we were able to assess the location of primary production and consequently to reveal countries mainly affected by water scarcity associated with import to satisfy Danish diets consumption. We found that while the vegan scenario scored the best environmental profile requiring 1489 L/cap/day calculated with the volumetric WF approach, it has the largest potential impacts on blue WSF of 10,477 L_H20-eq/cap/day. This study has shown that more than 90% of impacts on water consumption occur outside the national borders, as a consequence of large quantities of fruits and nuts imported by countries already threatened by high water scarcity conditions such as USA and Mediterranean regions. This methodological approach may be used to compare environmental performances of recommended dietary guidelines and to assess impact scenarios of new trade policies, protecting local water scarcity levels.

Considering the Fate of Evaporated Water Across Basin Boundaries-Implications for Water Footprinting

Water consumption along value chains of goods and services has increased globally and led to increased attention on water footprinting. Most global water consumption is accounted for by evaporation (E), which is connected via bridges of atmospheric moisture transport to other regions on Earth. However, the resultant source-receptor relationships between different drainage basins have not yet been considered in water footprinting. Based on a previously developed data set on the fate of land evaporation, we aim to close this gap by using comprehensive information on evaporation recycling in water footprinting for the first time. By considering both basin internal evaporation recycling (BIER; >5% in 2% of the world's basins) and basin external evaporation recycling (BEER; >50% in 37% of the world's basins), we were able to use three types of water inventories (basin internal, basin external, and transboundary inventories), which imply different evaluation perspectives in water footprinting. Drawing on recently developed impact assessment methods, we produced characterization models for assessing the impacts of blue and green water evaporation on blue water availability for all evaluation perspectives. The results show that the negative effects of evaporation in the originating basins are counteracted (and partly overcompensated) by the positive effects of reprecipitation in receiving basins. By aggregating them, combined net impacts can be determined. While we argue that these offset results should not be used as a standalone evaluation, the water footprint community should consider atmospheric moisture recycling in future standards and guidelines.

A method for assessing sustainability, with beef production as an example

A comprehensive approach to decisions about the use of land and other world resources, taking full account of biological and other scientific information, is crucial for good decisions to be made now and in future. The sustainability of systems for producing food and other products is sometimes assessed using too narrow a range of component factors. A production system might be unsustainable because of adverse effects on a wide range of aspects of human welfare, animal welfare, or the environment. All factors should be included in sustainability evaluation, otherwise products or actions might be avoided without adequate consideration of key factors or of the diversity of production systems. A scoring method that is based on scientific information and potentially of general relevance is presented here, using beef production as a example with a review of each of its sustainability components. This includes an overall combined score and specific factors that make the system unacceptable for some consumers. The results show that, in this example, the sustainability of the best systems is very much better than that of the worst systems. By taking account of scores for a wide range of components of sustainability in comparing beef-production systems, better quality policies about beef use can be formulated than when statements referring only to one system are considered. The least sustainable beef-production systems are extensive grazing that causes land degradation and the use of feedlots or indoor housing with grain feeding. Semi-intensive silvopastoral systems are the most sustainable beef-production systems, and well-managed pasture-fed beef from areas where crop production is uneconomic is also sustainable. This simple, scientifically based scoring system could be modified to use positive as well as negative scores and is of value for policy makers, researchers, producers, organisations aiming to improve sustainability, and the general public.

Individual US diets show wide variation in water scarcity footprints

Agriculture accounts for 80% of global freshwater consumption but the environmental impacts of water use are highly localized and depend on water scarcity. The water use impacts of food production should be a key consideration of sustainable diets, yet little is known of the water scarcity demands of diets, especially of individuals. Here we estimate the water scarcity footprint (WSF)-a water use impact metric that accounts for regional scarcity-of individual diets in the United States (n = 16,800) and find a fivefold variation between the highest and lowest quintile of diets ranked by WSF. Larger intakes of some meat, fruit, nuts and vegetables drive these differences. Meat consumption is the greatest contributor (31%) to the WSF of the average diet, and within that, beef contributes about six times that of chicken. Variation between substitutable foods provides insight into diet shifts that can reduce WSF. We introduce a novel, geospatially explicit approach that combines the types and quantities of foods in the diets of individuals, the irrigation water required to produce those foods and the relative scarcity of water where that irrigation occurs.

Life cycle assessment of fish and seafood processed products - A review of methodologies and new challenges

Life cycle assessment (LCA) has been widely applied in many different sectors, but the marine products and seafood segment have received relatively little attention in the past. In recent decades, global fish production experienced sustained growth and peaked at about 179 million tonnes in 2018. Consequently, increased interest in the environmental implications of fishery products along the supply chain, namely from capture to end of life, was recently experienced by society, industry and policy-makers. This timely review aims to describe the current framework of LCA and its application to the seafood sector that mainly focused on fish extraction and processing, but it also encompassed the remaining stages. An excess of 60 studies conducted over the last decade, along with some additional publications, were comprehensively reviewed; these focused on the main LCA methodological choices, including but not limited to, functional unit, system boundaries allocation methods and environmental indicators. The review identifies key recommendations on the progression of LCA for this increasingly important sustaining seafood sector. Specifically, these recommendations include (i) the need for specific indicators for fish-related activities, (ii) the target species and their geographical origin, (iii) knowledge and technology transfer and, (iv) the application and implementation of key recommendations from LCA research that will improve the accuracy of LCA models in this sector. Furthermore, the review comprises a section addressing previous and current challenges of the seafood sector. Wastewater treatment, ghost fishing or climate change, are also the objects of discussion together with advocating support for the water-energy-food nexus as a valuable tool to minimize environmental negativities and to frame successful synergies.

An assessment of the water use associated with Australian diets using a planetary boundary framework

OBJECTIVE

Agriculture accounts for around 70 % of global freshwater withdrawals. As such, the food system has been identified as a critical intervention point to address water scarcity. Various studies have identified dietary patterns that contribute less to water scarcity. However, it is unclear what level of reduction is necessary to be considered sustainable. The pursuit of unnecessarily aggressive reductions could limit dietary diversity. Our objective was to assess the sustainability of water use supporting Australian dietary habits and the adequacy of current dietary guidelines.

DESIGN

Dietary intake data were obtained from the National Nutrition and Physical Activity component of the Australian Health Survey. For each individual daily diet, the water scarcity footprint was quantified, following ISO14046:2014, as well as a diet quality score. Water scarcity footprint results were compared with the planetary boundary for freshwater use downscaled to the level of an individual diet.

SETTING

Australia.

PARTICIPANTS

9341 adults participating in the Australian Health Survey.

RESULTS

Dietary water scarcity footprints averaged 432·6 L-eq (95 % CI 432·5, 432·8), less than the 695 litres/person per d available to support the current global population of 7·8 billion, and the 603 litres/person per d available for a future population of 9 billion. Diets based on the Australian Dietary Guidelines required 521 L-eq/d, or 379 L-eq/d with lower water scarcity footprint food choices.

CONCLUSIONS

Diets based on the Australian Dietary Guidelines were found to be within the freshwater planetary boundary. What is needed in Australia is greater compliance with dietary guidelines.

The scarcity-weighted water footprint provides unreliable water sustainability scoring

To evaluate the environmental sustainability of blue water use or the blue water footprint (WF) of a product, organisation, geographical entity or a diet, two well-established indicators are generally applied: water efficiency and blue water stress. In recent years, the Life Cycle Assessment (LCA) community has developed, used and promoted the indicator scarcity-weighted WF, which aims to grasp both blue water use and blue water stress in one indicator. This indicator is now recommended in an ISO document on water footprinting and many scholars have used associated scarcity-weighted water use indicators. However, questions on its physical meaning and its ability to correctly evaluate water sustainability have emerged. Here, we analyse for global irrigated wheat production to what extend the scarcity-weighted WF addresses blue water stress and water efficiency. We observe inconsistent results, as a significant proportion of unsustainably produced irrigated wheat has better scarcity-weighted WF scores as compared to sustainably produced irrigated wheat. Using the scarcity-weighted WF or scarcity-weighted water use for policy-making including product labelling, punishes some farmers producing their wheat in a water-sustainable way and promotes some farmers producing wheat unsustainably. Applying the scarcity-weighted WF indicator thereby is contraproductive in reaching the Sustainable Development Goal (SDG) target 6.4 on reducing water stress. In line with the specifications of this SDG target, to evaluate the sustainability of blue water use or the blue WF, the two indicators water stress and water efficiency should be used separately, in a complementary way.

Shifting from volume to economic value in virtual water allocation problems: A proposed new framework and methodology

PURPOSE

The water footprint provided a full methodology to operationalise the virtual water concept (the volume of water used along a supply chain to produce products and services). A key theme in the water footprint literature is the efficient allocation of water resources at the global scale given the feasibility of trading water intensive commodities from water rich to water poor areas: this is an economic problem of resource allocation between alternative and competing demands, albeit with a novel international component. Moreover, given that price signals indicating relative scarcity are usually either absent or distorted for water, it is also a problem that can be seen through the lens of environmental (or non-market) valuation. However, to date environmental valuation has not been used to inform the efficient use and allocation of water within and between the different locations encompassed by international supply chains.

METHODS

Drawing on an agri-food supply chain framework that we propose in this paper, we begin by conceptualising the economic values that accrue to water consumption (blue and green water) and degradation (grey water) at different points along a supply chain. Based on this conceptualisation, we assess the extent to which it is possible to approximate these economic values by relying on existing secondary data on the shadow value of water in different contexts. The use of secondary data in this way is known as benefit (or value) transfer. To achieve this, 706 unit estimates of the economic value of water are collected, standardised and reviewed encompassing off-stream water applications (agriculture, industry and municipal) and in-stream ecosystem services (waste assimilation, wildlife habitat, recreation, hydrological functions and passive uses). From this, a proposed methodology for valuing virtual water is presented and illustrated using the case study of global durum wheat pasta production.

RESULTS

The case study shows the total value of the virtual water used to produce one tonne of durum wheat pasta ($212). More importantly, the case study also highlights how variations in economic value between multiple locations where durum wheat is cultivated (Saskatchewan $0.10 m³, Arizona $0.08 m³ and Baja California $0.24 m³) indicate relative water scarcity and thus impact, as well as the potential for a more efficient allocation of virtual water.

CONCLUSIONS

The main conclusion from this research is that when geographical disparities in the economic value of water use within a supply chain are accounted for, what was perhaps considered sustainable in volume terms, might not, in fact, represent the optimal allocation. However, future research opportunities highlight the need for additional data collection on the economic value of water in several contexts. This additional data would help the environmental valuation community to undertake a more comprehensive and robust approach to virtual water valuation. This paper is accompanied by the Data in Brief article entitled "Dataset on the in-stream and off-stream economic value of water."

Blue water footprint linked to national consumption and international trade is unsustainable

Increasing pressure on the world's freshwater resources raises serious concerns about global food security and the sustainability of water use in agriculture. Here we quantify and map at a 5-arcmin spatial resolution the blue water footprint of each country's national consumption and where they infringe sustainable environmental flows as defined by the presumptive environmental flow standard or the 80% rule, in which runoff depletion by more than 20% will pose risk to ecosystems. We find that 52% of the blue water footprint of global consumption and 43% of international blue virtual water flows come from places where the sustainable environmental flow is violated. About 22% of the environmental flow infringement of the blue water footprint of global consumption lies outside the specific countries of consumption, indicating that a number of them have externalized their impacts. By establishing a link between the consumption of a product in one place and water scarcity in places far from the place of consumption, our assessment may aid a dialogue on how to assign and share responsibilities concerning water use.

Water Resources for Sustainable Healthy Diets: State of the Art and Outlook

Sustainable healthy diets are high on the research and policy agendas. One of the crucial resources to provide such diets are water resources. This paper provides a brief overview of the current research state regarding this topic, with a focus on the water footprint concept, as latter quantifies water use along a supply chain. The water footprint (WF) quantifies blue and green water consumption, as both these water resources are essential for food and energy production as well as for the environment. Different kinds of information are embedded in a dietary WF and different data sources and modelling approaches exist, leading to WF dietary amounts that are not always directly comparable. A full sustainability assessment of a dietary WF encompasses three components: (1) an equity assessment of the total WF amount; (2) an efficiency assessment for each food item in the diet as well as (3) an impact assessment (blue water stress and green water scarcity) for each food item in the diet. The paper concludes with an outlook on future research on the topic, listing the following points: (1) future clarity in system boundary and modelling assumptions, with comparison of results between different approaches; (2) full sustainability assessments including all three components; (3) dietary footprint family assessments with the WF as one member; (4) WF assessments for multiple dietary regimes with support to the development of local dietary guidelines and (5) assessment of the synergies with LCA-based mid-point (scarcity-weighted WF) and end-point (especially human health) indicators and evaluation of the validity and empirical significance of these two indicators

Tracing the Consumption Origins of Wastewater and Sludge for a Chinese City Based on Waste Input-Output Analysis

Water scarcity and pollution are grand challenges to sustainability. We developed a high-resolution wastewater input-output model for a Chinese city, Xiamen, incorporating detailed information on the treatment and quality of wastewater and sludge. We estimated consumption-based wastewater and sludge footprints of products (W²F and SF, respectively). Significant differences were found between the amounts of direct discharge (scope 1) and W²F (scopes 1-3), indicating the need to consider W²F in making plans for future wastewater management strategies. Reflecting its high organic content, food-related consumption was found to be a significant contributor to sludge generation. Scenario analyses were conducted to assess the effects of a shift from the traditional Chinese diet to the European diet and the anticipated industrial growth. Attempts were also made to establish links between the direct wastewater discharge of households and the final consumption of food items through human excretion, or the postconsumption footprints. It was found that the postconsumption W²F outweighed the preconsumption W²F for five out of nine food items, while the postconsumption SF outweighed the preconsumption SF in all cases except one. This research provides a scientific basis to identify the economy-wide fate of wastewater and sludge and to frame a policy for sustainable wastewater and sludge management.

Sustainable food system policies need to address environmental pressures and impacts: The example of water use and water stress

Sustainable food systems are high on the political and research agendas. One of the three pillars of sustainability is environmental sustainability. We argue that, when defining related policies, such as policies under the European Green Deal, both environmental pressures and impacts carry important and complementary information and should be used in combination. Although the environmental focus of a sustainable food system is to have a positive or neutral impact on the natural environment, addressing pressures is necessary to achieve this goal. We show this by means of the pressure water use (or water footprint) and its related impact water stress, by means of different arguments: 1) Water use and water stress are only weakly correlated; 2) water use can be evaluated towards a benchmark, addressing resource efficiency; 3) water use is used for resource allocation assessments within or between economic sectors; 4) water amounts are needed to set fair share amounts for citizens, regions, countries or on a global level 5) the pressure water use requires less data, whereas water stress assessments have more uncertainty and 6) both provide strong communication tools to citizens, including for food packaging labelling. As a result, we present a water quantity sustainability scheme, that addresses both water use and water stress, and can be used in support of food system policies, including food package labelling.

Cradle-to-Gate Water-Related Impacts on Production of Traditional Food Products in Malaysia

Modern technology and life-style advancements have increased the demand for clean water. Based on this trend it is expected that our water resources will be under stress leading to a high probability of scarcity. This study aims to evaluate the environmental impacts of selected traditional food manufacturing products namely: tempe, lemang, noodle laksam, fish crackers and salted fish in Malaysia. The cradle-to-gate approach on water footprint assessment (WFA) of these selected traditional food products was carried out using Water Footprint Network (WFN) and Life Cycle Assessment (LCA). Freshwater eutrophication (FEP), marine eutrophication (MEP), freshwater ecotoxicity (FETP), marine ecotoxicity (METP) and water consumption (WCP), LCA were investigated using ReCiPe 2016 methodology. Water footprint accounting of blue water footprint (WFblue), green water footprint (WFgreen) and grey water footprint (WFgrey) were established in this study. It was found that total water footprint for lemang production was highest at 3862.13 m3/ton. The lowest total water footprint was found to be fish cracker production at 135.88 m3/ton. Blue water scarcity (WSblue) and water pollution level (WPL) of these selected food products were also determined to identify the environmental hotspots. Results in this study showed that the WSblue and WPL of these selected food products did not exceed 1%, which is considered sustainable. Based on midpoint approach adopted in this study, the characterization factors for FEP, MEP, FETP, METP and WCP on these selected food products were evaluated. It is recommended that alternative ingredients or product processes be designed in order to produce more sustainable lemang.

Water and wastewater management for sustainable viticulture and oenology in South Portugal – a review

Assessing sustainability of the wine industry requires improved characterization of its environmental impacts, namely in terms of water use. Therefore, quantification of water inputs and wastewater (WW) outputs is needed to highlight inefficiencies in wine production and related consequences for the environment. Water use and WW generation in irrigated viticulture and oenology remains insufficiently quantified for dry Mediterranean regions (e.g. South Portugal). This paper is focused on wine production under warm and dry climate conditions in the winegrowing region of Alentejo (South Portugal). This region experiences increasingly dry conditions, while the irrigated area keeps expanding, which puts exacerbates the pressure on existing local and regional water resources. Additionally, more erratic variation in climate conditions and the tendency for increasingly extreme climate events (e.g. heat waves) pose more challenges to Alentejo’s wine sector. We conclude that quantitative information on water use and management is not always easy to obtain or access, which hinders improved strategies and/or policies for water use at farm, winery and region-level. Up-to-date statistics and robust metrics can help to better characterize water use and WW flows for Alentejo’s wine region, while optimizing management in vineyards and wineries, in companies and region-wide. The paper is focused on a “Farm-Winery” scenario, which is the most common in South Portugal’s wine sector

Spatial-temporal characteristics of China's industrial wastewater discharge at different scales

Industrial wastewater is one of the three industrial wastes. If substandard industrial wastewater is discharged into the environment, there will be a serious impact on the environmental quality. Excessive emissions also indicate that water resources utilization is unreasonable. Therefore, it is of great significance to study the changing trends and influencing factors of industrial wastewater discharge in order to effectively conserve resources and improve the environmental quality. In this study, the spatial autocorrelation and the environmental Kuznets curve were used to study the spatial-temporal changes and characteristics of industrial wastewater discharge at the provincial scale and prefectural scale in China in 2004-2015. Then, the Logarithmic Mean Divisia Index was used to analyze the influencing factors of wastewater discharge in this period. China's total industrial wastewater discharge showed a trend of increasing at the beginning and then decreasing, and more than half provinces or cities show this trend of decoupling from economic development. Moreover, wastewater discharge was higher in the east region and lower in the west region at both the provincial scale and prefectural scale, but the aggregation degree on the prefectural scale is more obvious than that on the provincial scale. The technical effect has a general inhibitory effect on industrial wastewater discharge, but it also promoted the discharge in a few cities; the structure effect on industrial wastewater discharge has generally changed from promotion to inhibition during the study period; and economic effect and population effect were mainly to promote industrial wastewater discharge. Therefore, a few cities should accelerate technology upgrading and industrial restructuring in recent years in order to change the promoting effect, and most cities need to strengthen the implementation of economic measures and improve the residents' environmental awareness.

A Methodological Framework for Developing More Just Footprints: The Contribution of Footprints to Environmental Policies and Justice

The rapid growth of human population and associated industrialisation creates strains on resources and climate. One way to understand the impact of human activity is to quantify the total environmental pressures by measuring the 'footprint'. Footprints account for the total direct and/or indirect effects of a product or a consumption activity, which may be related to e.g. carbon, water or land use, and can be seen as a proxy for environmental responsibility. Footprints shape climate and resource debates, especially concerning environmental strategies. However, in general, footprints hold a dichotomous producer-consumer perspective that is not unanimously accepted. In addition, the current footprinting system transmits a simplistic message about environmental responsibility that taints the justice debate and jeopardises the validity of policies based on them. Consequently, it is crucial to question who is (and should be) accountable for adverse environmental effects. It is also critical to investigate how the methodological characteristics of footprints shape and affect the efficacy of policies on climate and natural resources. This article examines these challenges, focusing on negative justice and policy implications resulting from assigning environmental responsibility to a sole agent. The article proposes, and morally justifies, the development of a footprinting method that includes justice parameters in an attempt to render fair results that are more meaningful for environmental action. The second objective is to establish the potential of this new framework to promote environmental responsibility and justice while facilitating policymaking. The suggested justice elements aim at turning footprints into a concrete environmental policy instrument framed under the value of environmental fairness.

Evaluation of Water Scarcity Footprint for Taiwanese Dairy Farming

Raw milk production in Taiwan has increased year after year, which means that the environmental impact might also be intensified in certain regions. To balance both consumer demand and environmental sustainability, evaluating the potential impact and understanding the causal relationship between production and environment is imperative. This study applied the life cycle assessment (LCA) protocol to explore water consumption for raw milk production from cradle to farm gate of five dairy farms in Hsinchu County and evaluate the stress-weighted water scarcity footprint (WSF) as well as the water scarcity productivity (WSP) of the 16 Taiwanese counties and cities. Results indicated that the highest stress-weighted WSF of the dairy farms for raw milk production was located in northern and central Taiwan and was around 44.8 H₂O_eq/kg fat- and protein-corrected milk (FPCM). On the other hand, both the smallest stress-weighted WSF (about 2.2 H₂O_eq/kg FPCM) and the highest WSP (0.749 kg FPCM/m³ water) of the dairy farms were located in Nantou and Chiayi Counties, because these two counties were the least water-stressed regions in Taiwan. The achievement of this study could be the first and important reference for the sustainable production of raw milk and optimizing the industrial policy of dairy farming by policy makers.

Water Footprint Assessment of Selected Polymers, Polymer Blends, Composites, and Biocomposites for Industrial Application

This paper presents a water footprint assessment of polymers, polymer blends, composites, and biocomposites based on a standardized EUR-pallet case study. The water footprint analysis is based on life cycle assessment (LCA). The study investigates six variants of EUR-pallet production depending on the materials used. The system boundary included the production of each material and the injection molding to obtain a standardized EUR-pallet of complex properties. This paper shows the results of a water footprint of six composition variants of analyzed EUR-pallet, produced from biocomposites and composites based on polypropylene, poly(lactic acid), cotton fibers, jute fibers, kenaf fibers, and glass fibers. Additionally, a water footprint of applied raw materials was evaluated. The highest water footprint was observed for cotton fibers as a reinforcement of the analyzed biocomposites and composites. The water footprint of cotton fibers is caused by the irrigation of cotton crops. The results demonstrate that the standard EUR-pallet produced from polypropylene with glass fibers as reinforcement can contribute to the lowest water footprint.

Impact of shale gas development on regional water resources in China from water footprint assessment view

Shale gas production in China could strengthen energy security while cutting CO₂ emissions for China. However, the availability of and access to water could become major issue for shale gas development in certain parts of China. This study aims to estimate the water intensity (WI) of shale gas extraction in China, and to examine the impact of regional shale gas development on local water resources, from the water footprint (WF) point of view. Results of this study indicate that WI of shale gas is in the range of 0.3-9.9 kg per m³ shale gas produced. For a single well, total WF is 549,994 m³, includes 35,469 m³ blue WF and 514,525 m³ grey WF. A large amount of wastewater generated during gas production is the major impact factor to high grey WF. To achieve 80 billion m³/year of shale gas production in 2030, 27-792 million m³ water will be demanded in that year. Water use for shale gas development will account for 0.03-0.4% and 0.1-1.5% of the local water supply, in the base case and the worst case, respectively. Although a large amount of water will be demand for shale gas production, it will not affect the local water supply significantly.

Water use indicators at farm scale - An agro-hydrological software solution

The challenge to sustainably intensify agricultural production in farming systems in face of the increasing variability in regional water resources requires concerted action from many stakeholders, locally, regionally and globally. Models, such as the AgroHyd Farmmodel presented here, can provide information on how farm management decisions affect local water resources at various scales for use in multiple assessment frameworks. It is a stand-alone web-based software that connects agricultural and water-related systems, including all water flows related to farming systems. Results from a case study of the production of 12 crops with rainfed and supplemental irrigation on a farm in northeastern Germany are described here. Indicators that relate the water use to plant production on the farm such as water intensity or water productivity are compared in detail for three consecutive years with greatly varying annual rainfall amounts (from 373 to 790 mm) to highlight the effect of local variability on water flows and indicator values. The discussion illustrates how information on the effect of management decisions, such as crop type, seeding date, crop rotation, cultivation and irrigation on water use can be processed into indicators to help farmers make more effective decisions.

Diet Quality and Water Scarcity: Evidence from a Large Australian Population Health Survey

There is widespread interest in dietary strategies that lower environmental impacts. However, various forms of malnutrition are also widely prevalent. In a first study of its kind, we quantify the water-scarcity footprint and diet quality score of a large (>9000) population of self-selected adult daily diets. Here, we show that excessive consumption of discretionary foods—i.e., energy-dense and nutrient-poor foods high in saturated fat, added sugars and salt, and alcohol—contributes up to 36% of the water-scarcity impacts and is the primary factor differentiating healthier diets with lower water-scarcity footprint from poorer quality diets with higher water-scarcity footprint. For core food groups (fruits, vegetables, etc.), large differences in water-scarcity footprint existed between individual foods, making difficult the amendment of dietary guidelines for water-scarcity impact reduction. Very large reductions in dietary water-scarcity footprint are possible, but likely best achieved though technological change, product reformulation and procurement strategies in the agricultural and food industries.

Is the nitrogen footprint fit for purpose? An assessment of models and proposed uses

The nitrogen footprint has been proposed as an environmental indicator to quantify and highlight how individuals, organizations, or countries contribute to nitrogen pollution. While some footprint indicators have been successful in raising awareness of environmental pressures among the public and policy-makers, they have also attracted criticism from members of the life cycle assessment (LCA) community who find some footprints confusing and misleading as they measure substance and energy flows without considering their environmental impacts. However, there are also legitimate reasons to defend footprints as a useful class of indicators despite their incompatibility with LCA principles. Here, in light of this previous research and debate, we critically assess models and proposed uses for the nitrogen footprint, and explore options for further development. As the nitrogen footprint merely quantifies gross nitrogen emissions irrespective of time, location, and chemical form, it is a crude proxy of environmental and health impacts compared to other, more sophisticated environmental impact indicators. However, developing the nitrogen footprint toward LCA-compatible impact assessment would imply more uncertainty, more complexity, and more work. Furthermore, we emphasize that impact assessment has an unavoidable subjective dimension that should be recognized in any development toward impact assessment. We argue that the nitrogen footprint in its present form is already fit for some purposes, and therefore further development towards impact assessment may be unnecessary or even undesirable. For some uses it seems more important that the footprint has a clear physical meaning. We conclude that the best way forward for the nitrogen footprint depends crucially on what story it is used to tell.

Developing and exploring indicators of water sustainable development

The pressures of rapid economic growth, population increase, and global warming are stretching the availabilities of natural freshwater sources which have implications for economic prosperity and human life. Water resources are entwined in a complex socio-economic system, affected by water demands as well as the environmental implications of pollution and waste discharges. Drawing on existing measures of social and economic wellbeing, this research presents the development of indicators that place economic growth within the context of social and environmental development, presenting a measure that assesses how water resources are used in a manner that is efficient and beneficial to society as a whole. From a study of 37 nations, the findings show that in countries with relatively high (by global standards) economic and social development, there is a discrepancy between social development and the productive use of water resources. This opens up potential applications for policy makers and industry leaders to monitor and measure their progress towards water sustainable practices and enable international comparisons of water sustainable development.

Cities as hotspots of indirect water consumption: The case study of Hong Kong

During the last years, the city of Hong Kong has made large investments to make its urban water supply system more water efficient and sustainable. As such, its municipal water abstraction - often defined as direct water use - has decreased from 355 litre per capita per day (l/cap/d) in 2005 to 326 l/cap/d in 2013. Due to its political history, Hong Kong is unique in the world in data availability on urban food consumption. It is therefore the ideal case study to show typical urban food consumption behaviour and its related indirect water use. The objective of this paper is to show the large water quantities associated with indirect water use and that the citizens of Hong Kong can additionally save much more water by looking at this indirect water use. The current average diet in Hong Kong is very different to the average Chinese diet. It is characterised by a high intake of water intensive products like animal products and sugar, leading to a food related indirect water use or water footprint (WF_cons) of 4727 l/cap/d. According to recommendations from the Chinese Nutrition Society for a healthy diet, the intake of some product groups should be increased (vegetables and fruit) and of other product groups reduced (sugar, crop oils, meat and animal fats). This would result in a reduction of the WF_cons of 40% to 2852 l/cap/d. Especially the reduced intake of meat (including offals) from currently 126 kg per capita per year (kg/cap/yr) to the recommended value 27 kg/cap/yrwould results in a substantial WF_cons reduction. Meat consumption in Hong Kong is extremely high. A pesco-vegetarian diet would result in a reduction of 49% (to 2398 l/cap/d) and a vegetarian diet in a 53% (to 2224 l/cap/d) reduction. Hong Kong citizens can thus save a lot of water through a change in their diet. Many of the products consumed, contribute to different levels of blue water scarcity in the regions of origin Hong Kong imports from. This poses a water-related risk to food security in Hong Kong. As all diet scenarios also result in a lower blue WF_cons, they decrease this risk. In order to become sustainable, (mega)cities should reduce their dependency on distant resources and ecosystems.

A comparison of the Mediterranean diet and current food consumption patterns in Spain from a nutritional and water perspective

The promotion of responsible consumption is a key strategy to achieve environmental benefits, sustainable food security, and enhance public health. Countries like Spain are making efforts to reverse growing obesity and promote healthy diets, such as the recommended and traditional Mediterranean, recognized as a key strategy to improve the population's health with locally grown, traditional, and seasonal products like fruits, vegetables, olive oil, and fish. With a view to connecting water, agriculture, food security, nutrition and health, this research aims to investigate and compare the nutritional and water implications of the current food consumption of Spanish households with the recommended Mediterranean diet. Besides, we calculate their nutritional composition, compare their water footprints, and develop a new methodological approach to assess nutritional water productivity (i.e. the nutritional value per unit of embedded water). Results show that the current Spanish diet is shifting away from the recommended Mediterranean towards an alternative one containing three times more meat, dairy and sugar products, and a third fewer fruits, vegetables, and cereals. The Mediterranean diet is also less caloric, as it contains smaller amounts of proteins and fats and is richer in fiber and micronutrients. Due to the high-embedded water content in animal products, a shift towards a Mediterranean diet would reduce the consumptive WF about 750 l/capita day. Additionally, the Mediterranean diet has better water-nutritional efficiency than the current one: it provides more energy, fiber, and nutrients per liter of consumptive water. The study confirms the Mediterranean diet is a healthier and more sustainable diet with strong cultural heritage.

A Prospective Life Cycle Assessment (LCA) of Monomer Synthesis: Comparison of Biocatalytic and Oxidative Chemistry

Biotechnological processes are typically perceived to be greener than chemical processes. A life cycle assessment (LCA) was performed to compare the chemical and biochemical synthesis of lactones obtained by Baeyer-Villiger oxidation. The LCA is prospective (based on experiments at a small scale with primary data) because the process is at an early stage. The results show that the synthesis route has no significant effect on the climate change impact [(1.65±0.59) kg CO 2  g_product ^-1 vs. (1.64±0.67) kg CO 2  g_product ^-1 ]. Key process performance metrics affecting the environmental impact were evaluated by performing a sensitivity analysis. Recycling of solvents and enzyme were shown to provide an advantage to the enzymatic synthesis. Additionally, the climate change impact was decreased by 71 % if renewable electricity was used. The study shows that comparative LCAs can be used to usefully support decisions at an early stage of process development.

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.

Marrying Unmarried Literatures: The Water Footprint and Environmental (Economic) Valuation

In this commentary, we set out the rationale for bringing together two research fields: Water Footprint Assessment and environmental (economic) valuation, which have evolved separately. This has the potential to inform the efficient allocation of virtual water flows at a global scale. It would also address some of the aims and objectives in the Water Footprint Assessment Manual regarding the assessment of environmental impacts and their sustainability, which thus far have not been covered in the literature. We also indicate how established practice in the environmental valuation community would need to develop to facilitate productive exchange between the two fields. Finally, we outline the key developments in the non-peer reviewed grey literature that signal the merit of such an exchange.

Water impacts of U.S. biofuels: Insights from an assessment combining economic and biophysical models

Biofuels policies induce land use changes (LUC), including cropland expansion and crop switching, and this in turn alters water and soil management practices. Policies differ in the extent and type of land use changes they induce and therefore in their impact on water resources. We quantify and compare the spatially varying water impacts of biofuel crops stemming from LUC induced by two different biofuels policies by coupling a biophysical model with an economic model to simulate the economically viable mix of crops, land uses, and crop management choices under alternative policy scenarios. We assess the outputs of an economic model with a high-resolution crop-water model for major agricultural crops and potential cellulosic feedstocks in the US to analyze the impacts of three alternative policy scenarios on water balances: a counterfactual 'no-biofuels policy' (BAU) scenario, a volumetric mandate (Mandate) scenario, and a clean fuel-intensity standard (CFS) scenario incentivizing fuels based on their carbon intensities. While both biofuel policies incentivize more biofuels than in the counterfactual, they differ in the mix of corn ethanol and advanced biofuels from miscanthus and switchgrass (more corn ethanol in Mandate and more cellulosic biofuels in CFS). The two policies differ in their impact on irrigated acreage, irrigation demand, groundwater use and runoff. Net irrigation requirements increase 0.7% in Mandate and decrease 3.8% in CFS, but in both scenarios increases are concentrated in regions of Kansas and Nebraska that rely upon the Ogallala aquifer for irrigation water. Our study illustrates the importance of accounting for the overall LUC and shifts in agricultural production and management practices in response to policies when assessing the water impacts of biofuels.

Product Environmental Footprint (PEF) Pilot Phase—Comparability over Flexibility?

The main goal of the European product environmental footprint (PEF) method is to increase comparability of environmental impacts of products within certain product categories by decreasing flexibility and therefore achieving reproducibility of results. Comparability is supposed to be further increased by developing product category specific rules (PEFCRs). The aim of this paper is to evaluate if the main goal of the PEF method has been achieved. This is done by a comprehensive analysis of the PEF guide, the current PEFCR guide, the developed PEFCRs, as well as the insights gained from participating in the pilot phase. The analysis reveals that the PEF method as well as its implementation in PEFCRs are not able to guarantee fair comparability due to shortcomings related to the (1) definition of product performance; (2) definition of the product category; (3) definition and determination of the representative product; (4) modeling of electricity; (5) requirements for the use of secondary data; (6) circular footprint formula; (7) life cycle impact assessment methods; and (8) approach to prioritize impact categories. For some of these shortcomings, recommendations for improvement are provided. This paper demonstrates that the PEF method has to be further improved to guarantee fair comparability.

A Multimedia Hydrological Fate Modeling Framework To Assess Water Consumption Impacts in Life Cycle Assessment

Many new methods have recently been developed to address environmental consequences of water consumption in life cycle assessment (LCA). However, such methods can only partially be compared and combined, because their modeling structure and metrics are inconsistent. Moreover, they focus on specific water sources (e.g., river) and miss description of transport flows between water compartments (e.g., from river to atmosphere via evaporation) and regions (e.g., atmospheric advection). Consequently, they provide a partial regard of the local and global hydrological cycle and derived impacts on the environment. This paper proposes consensus-based guidelines for a harmonized development of the next generation of water consumption LCA indicators, with a focus on consequences of water consumption on ecosystem quality. To include the consideration of the multimedia water fate between compartments of the water cycle, we provide spatial regionalization and temporal specification guidance. The principles and recommendations of the paper are applied to an illustrative case study. The guidelines set the basis of a more accurate, novel way of modeling water consumption impacts in LCA. The environmental relevance of this LCA impact category will improve, yet much research is needed to make the guidelines operational.

Assessing the magnitude of potential environmental impacts related to water and toxicity in the Peruvian hyper-arid coast: A case study for the cultivation of grapes for pisco production

The environmental sustainability of the cultivation of grapes for the production of alcoholic beverages has been extensively analyzed in the literature from a Life Cycle Assessment perspective, although certain impact categories have been repeatedly neglected despite their importance, such as toxic emissions or the depletion of freshwater resources. Hence, the current study provides a detailed assessment of water footprint-related impact categories, including toxicity, for the cultivation of grapes for pisco production, an alcoholic beverage produced in coastal Peru in hyper-arid areas that suffer high levels of water scarcity. Characterization factors at a sub-watershed level were used to calculate water consumption impact assessment of grape production using the AWARE method. Site-specific toxic emissions were modelled using the PestLCI model, considering primary climate and soil data. The USEtox assessment method was then used to compute freshwater eco-toxicity with these data. Results demonstrate the high water footprint of irrigating vineyards in coastal Peru, especially considering the inefficient flooding irrigation process. In terms of water consumption, despite the high variability shown between sub-watersheds, the shift to other irrigation technologies must be analyzed with care due to the high competition for water existing in the area. Eutrophication potential showed particularly high values compared to the literature, whereas freshwater eco-toxicity impacts were relatively low due to the high volatilization of pesticides to air. Nevertheless, the lack of an adequate wastewater management system implies that the estimated potential toxic and eutrophying emissions may constitute a further environmental threat to water bodies.

Dietary Strategies to Reduce Environmental Impact: A Critical Review of the Evidence Base

The food system is a major source of environmental impact, and dietary change has been recommended as an important and necessary strategy to reduce this impact. However, assessing the environmental performance of diets is complex due to the many types of foods eaten and the diversity of agricultural production systems and local environmental settings. To assess the state of science and identify knowledge gaps, an integrative review of the broad topic of environment and diet was undertaken, with particular focus on the completeness of coverage of environmental concerns and the metrics used. Compared with the 14 discrete environmental areas of concern identified in the United Nations Sustainable Development Goals, the located journal literature mainly addressed greenhouse gas (GHG) emissions and, to a lesser extent, land and water use. Some relevant concerns were rarely addressed or not addressed at all. In the case of GHG emissions, changes in land use and soil carbon stocks were seldom considered. This represents a disconnect between the science informing strategic climate action in the agricultural sector and the science informing public health nutrition. In the case of land and water use, few studies used metrics that are appropriate in a life-cycle context. Some metrics produce inherently biased results, which misinform about environmental impact. The limited evidence generally points to recommended diets having lower environmental impacts than typical diets, although not in every case. This is largely explained by the overconsumption of food energy associated with average diets, which is also a major driver of obesity. A shared-knowledge framework is identified as being needed to guide future research on this topic. Until the evidence base becomes more complete, commentators on sustainable diets should not be quick to assume that a dietary strategy to reduce overall environmental impact can be readily defined or recommended.

The Water Footprint of Hydropower Production-State of the Art and Methodological Challenges

This paper reviews published estimates of water consumption from hydropower production and the methodologies applied. Published values range from negative to more than 115 000 m3 MWh-1. Most gross water consumption rates are in the range 5.4-234 m3 MWh-1, while most net values are in the range 0.2-140 m3 MWh-1. Net values are often less than 40% of the gross values, sometimes only 1% of the gross water consumption estimates. The extremely wide range in estimates is explained by an inconsistent methodology and the very site-specific nature of hydropower projects. Scientific challenges, such as allocation from multipurpose reservoirs, and spatial assignments in river basins with several hydropower plants, affect the results dramatically and remain unresolved. As such, it is difficult to propose "typical values" for water consumption from hydropower production. This paper points out directions of research in order to prepare a consistent and improved methodology for the calculation of water consumption from hydropower projects. This should take into account the role of reservoirs in the provision of a large range of water services, as well as providing regulated power to the energy system.