Blueing green water from forests as strategy to cope with climate change in water scarce regions: The case of the Catalan river basin District.

Water scarcity in Mediterranean basins is a critical concern exacerbated by climate change and afforestation of abandoned lands. This study addresses the impact of forest management on water availability, specifically blue water, at a regional scale. Utilizing the SWAT + model, we assess water yield increases resulting from various forest thinning scenarios (light, moderate, heavy) and compare benefits to costs. Our approach incorporates site-specific marginal values of water yield, accounting for urban water supply abstractions. The findings reveal the efficacy of hydrological-oriented forest management in alleviating water scarcity. Thinning intensity positively correlates with water yield, with coniferous forests exhibiting the greatest response and deciduous forests the least. Emphasizing blue water enhancement as a significant co-benefit in forest management planning, our study underscores the economic advantages. Particularly valuable in certain areas, this approach can offset a substantial portion of associated costs. Spatially explicit results enable optimal resource allocation, facilitating efficient planning and prioritization of intervention areas for successful hydrological-oriented strategies. In conclusion, our study not only highlights the economic benefits of forest management in enhancing water availability but also offers actionable insights for sustainable and effective hydrological-oriented planning amid escalating water scarcity.

Optimal allocation of agricultural water resources in Yanghe watershed considering blue water to green water ratio.

BACKGROUND: Yanghe Watershed has low annual rainfall, uneven spatial and temporal distribution, extreme shortage of water resources in some areas. The contradiction between supply and demand of water for agricultural production is prominent and the expected production value cannot be achieved. Therefore, it is necessary to investigate the supply and demand of agricultural water resources and the impact of green water on agricultural crops in Yanghe Watershed. RESULTS: This article proposes a new crop economic model for increasing the green-water footprint to blue-water footprint ratio (GWF:BWF) in accordance with the regional characteristics, alleviating agricultural water shortage in irrigation areas, optimizing water resource allocation, and achieving sustainable agricultural development. The proposition is based on a study of five crops in eight districts and counties in the Yanghe River watershed. By combining the economic model F with a crop water production function, we achieved 89.3%, 88.9%, 97.1%, 81.5%, and 87.0% of the optimal water demands of the five crops, respectively, and effectively improved the underground irrigation of crops and the water resource utilization efficiency. CONCLUSION: The GWF:BWF threshold interval was subsequently selected based on the temporal changes in the BWF and GWF in the study area. This enabled significant reduction of the planting area of blue-water crops and increase in the proportion of green-water crops, while also improving the agricultural economy of the Yanghe Watershed. The proposed model promises to afford enhanced management of agricultural irrigation areas that experience rainfall shortage. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Classification analysis of blue and green water quantities for a large-scale watershed of southwest China.

Traditional blue water resources assessment and management may not meet the needs of sustainable water resource utilization; ignoring the number of green water resources will underestimate the availability of water resources. To rationally allocate and scientifically manage the limited water resources, it is necessary to divide the rich and poor flow situation of blue water and green water. The MIKE SHE-MIKE HYDRO integrated coupled model was selected and used in the Yalong River basin to ascertain the blue and green water in the hydrological cycle. The model was calibrated by matching simulated discharge against observed streamflow discharge at the Tongziling Station. At the same time, the research analyzed the component of green water and the total amount of blue water or green water on a temporal scale. The set pair analysis (SPA) was introduced to classify blue water and green water, which can not only understand the amount and distribution characteristics of water resources in the Yalong River Basin but also rationally allocate the total of water resources in the basin from the perspective of the regional water cycle. Furthermore, according to the situation of blue water and green water in the basin, the related policies are formulated to realize the efficient utilization of water resources in the Yalong River basin.

Water footprint of small-scale dairy farms in the central coast of Peru.

Worldwide, dairy sector consumes 19% of the water in the livestock sector. However, in Latin America, the amount of water used in this sector is unknown, especially in arid zones. On the other hand, water footprint (WF) is a methodology to estimate the use of water to produce a product. The aim of this work was to estimate the WF of dairy production in the arid zone of the Peruvian central coast. Data from five dairy farms were used. The WF was calculated in its three dimensions: green water, blue water and grey water. In addition, the WF was measured for categories: feed, drinking and service. To measure the WF of feed production, the CROPWAT software was used, whilst the NRC (2001) equations were used to estimate the drinking water. The reference unit was cubic metres per kilogram of fat and protein corrected milk (FPCM). In average, 99% of the WF comes from feed production, followed by drinking water (0.4%). From the three dimensions of the WF, green water is responsible of 60% of the WF, followed by the blue water (30%). Imported water represented 63% of the WF. In general, WF of dairy production in these systems was 0.66 m3/kg FPCM. In conclusion, feed production, as the main source of WF from which most is imported, shows the possibility of reducing the WF of these systems by prioritizing and optimizing water consumption by crops using local resources with lower water requirements.

Impact of climate change on hydrology components using CORDEX South Asia climate model in Wunna, Bharathpuzha, and Mahanadi, India.

Detecting the probable impact of climate change responses on hydrological components is most important for understanding such changes on water resources. The impact of climate change on virtual parameters of water was assessed through hydrological modeling of the Wunna, Mahanadi (Middle), and Bharathpuzha watersheds. In this article, future hydrological component responses under two Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios were considered for investigating the runoff, sediment, and water storage components. RegCM4 CSIRO-Mk3.6.0 CORDEX South Asia of RCM model was used which is specially downscaled for the Asian region by IITM-India. Delta change method was adopted to remove bias correction in RCM data. Hydrological simulation for current and future periods was performed by GIS interfaced Soil Water and Assessment Tool (SWAT) model. The surface runoff of Wunna and Bharathpuzha watersheds and the yield of sediment are expected to increase further under RCP8.5 than RCP4.5 and in contrast to Mahanadi watershed. Both blue water storage (BW) and green water storage (GWS) of Wunna watershed are expected to decline under RCP4.5, and rise under RCP8.5 scenario. Both BW and GWS of Bharathpuzha are expected to increase in the future except in western region under RCP4.5 scenario. BW of Mahanadi is expected to increase in the future. However, GWS will decrease in some of the sub-basins. The model-generated results will be helpful for future water resources planning and development.

Environmental impacts on water resources from summer crops in rainfed and irrigated systems.

Irrigation is an intensification technology to increase productivity in agricultural systems, but the impacts of irrigation on the environmental performance of crops are not well understood. We evaluated impacts on water use and quality of rainfed and irrigated systems for corn and soybean production in temperate South America using nonparametric ANOVA tests for small sample sizes. We modeled blue water footprint, ecotoxicity, N and P balance, and eutrophication potential for six farms producing corn and soybean in rainfed and irrigated systems in Uruguay. Crop yields were 5948 and 7862 kg ha-1 for corn and 2482 and 3423 kg ha-1 for soybean, under rainfed and irrigation, respectively. The average blue water footprint for irrigated systems was 264 m3 ton-1 and zero for rainfed systems, with no difference between corn and soybean. The ecotoxicity was greater for soybean than for corn (1679 vs 325 CTUe kg-1) but there were no statistically significant differences in ecotoxicity between rainfed and irrigated systems. Based on Usetox methodology, insecticides had a greater ecotoxic effect (3.2 × 106 CTUe ha-1) than herbicides (7.3 × 104 CTUe ha-1), despite the lower doses applied (insecticides: 0.51 kg ha-1; herbicides: 6.83 kg ha-1). The aquatic eutrophication potential (based on Impact 2002 + methodology) among rainfed and irrigated systems presented no differences (29 vs 24 kgPO4-eq ha-1 for corn and 19 vs 27 kgPO4-eq ha-1 for soybean). The standardized environmental impacts for corn calculated per ha were similar than those per kg of grain when comparing rainfed vs irrigated systems. For soybean, however, standardized environmental impacts per ha were greater in the irrigated than in the rainfed systems, but were similar per kg of grain (except for water footprint). In summary, irrigation resulted in higher productivity and increased blue water footprint than rainfed, but in the set of farms analyzed it did not significantly increase inputs use, so no differences were detected in nutrient balance, eutrophication potential, or ecotoxicity. Soybeans had greater environmental impacts than corn in ecotoxicity and N excess per unit of area, but no statistically significant difference was found in the other indicators. These indicators may be useful as a predictive tool for resource management. Decision makers should consider the trade-offs between productivity, water use, and water quality when using irrigation for intensification of crop production.

Internal (blue) water footprint of municipal consumption: a case study for Turkey.

This study aimed to develop a common approach to investigate (blue) water footprint of consumption of municipalities. Analysis framework consists of two distinct phases as: water abstraction profile and water distribution and water use profile. In the proposed approach municipal water footprint (WFmunicipal) comprises three components: domestic water footprint (WFdomestic), industrial/commercial water footprint (WFindustrial/commercial), and public water footprint (WFpublic). The application of the methodology was demonstrated in Turkey. The overall objective was to identify water consumption profile regarding model components and assess spatial and temporal distributions in the country scale. In this scope, each component was determined for 81 cities. After the investigation of spatial differences, an answer to the question of, "whether water use is increasing or decreasing over time" was found. Results investigated that WFmunicipal was 140 L/ca.day in average and reached up to 300 L/ca.day in some cities. WFdomestic was about 100 L/ca.day and cities having lower values mostly located on north-west, south-east of the country. Furthermore, few spots with high values were observed for WFindustrial/commercial (with 10 L/ca.day average), and relatively lower values belonged to the cities in south-eastern region. WFpublic having 30 L/ca.day mean value had extremes in eastern part. Based on water consumption characteristics, cities were grouped using factor analysis and results created four groups of cities. Although eastern and western cities had no trends in water abstraction rate, other regions had decreasing trend in last 20 years. Investigation of (blue) water footprint of consumption of municipalities is believed to assist water managers to identify water use profiles and assess spatial and temporal distributions. This is important because water resources are becoming increasingly stretched to accommodate continued population and economic growth and to restore environmental flows.

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

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.

Field-based experimental water footprint study of sunflower growth in a semi-arid region of China.

BACKGROUND: Field-scale changes in the water footprint during crop growth play an important role in formulating sustainable water utilisation strategies. This study aimed to explore field-scale variation in the water footprint of growing sunflowers in the western Jilin Province, China, during a 3-year field experiment. The goals of this study were to (1) determine the components of the 'blue' and 'green' water footprints for sunflowers sown with water, and (2) analyse variations in water footprints and soil water balance under different combinations of temperature and precipitation. Specific actions could be adopted to maintain sustainable agricultural water utilisation in the semi-arid region based on this study. RESULTS: The green, blue, and grey water footprints accounted for 93.7-94.7%, 0.4-0.5%, and 4.9-5.8%, respectively, of the water footprint of growing sunflowers. The green water footprint for effective precipitation during the growing season accounted for 58.8% in a normal drought year but 48.2% in an extreme drought year. When the effective precipitation during the growing season could not meet the green water use, a moisture deficit arose. This increase in the moisture deficit can have a significant impact on soil water balance. CONCLUSION: Green water was the primary water source for sunflower growth in the study area, where a scarcity of irrigation water during sunflower growth damaged the soil water balance, particularly in years with continuous drought. The combination of temperature and precipitation effected the growing environment, leading to differences in yield and water footprint. The field experiments in this area may benefit from further water footprint studies at the global, national and regional scale. © 2016 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The food security risks in the Yangtze River Delta of China associated with water scarcity, grain production, and grain trade.

Grain production consumes a large amount of water and is affected by the degree of water scarcity and participation in the grain trade in various regions. The grain trade has changed the food security risks in regions where grain exports and imports. Therefore, it is crucial to consider regional water scarcity to understand food security risks from the grain trade network. Here, we construct a new framework for measuring regional food security risks associated with water scarcity, grain production, and grain trade based on a cross-city grain trade network combined with virtual water flows to evaluate the regional food security risks in the Yangtze River Delta region (YRD) of China in 2017. The results show that under the current domestic grain trade pattern in China, the YRD and its four provincial-level administrative regions are in a net grain import state. The grain trade within the YRD is concentrated in exports from the two major grain-producing areas of Anhui and Jiangsu to Zhejiang and Shanghai, especially from northern Jiangsu to southeastern Zhejiang. The net import results of virtual blue water in most cities indicate that the YRD has shifted its water resource pressure to other grain exporting regions in China, with Shanghai and Zhejiang being the greatest beneficiaries. Extreme risk only exists in Shanghai, and severe and moderate risks are concentrated in Jiangsu. The current grain trade has reduced the overall food security risk in the YRD by 1.3 % but increased the risks in Shanghai and Zhejiang by 2.1 % and 0.8 % respectively. This study highlights the potential risks that excessive production of food in water-scarce areas in the grain trade system may bring to a stable food supply, providing useful information for a comprehensive understanding of the food and water security situation and for future trade-offs.

A novel partitioning of gross primary production and water use efficiency for sustaining water and food security using Budyko hypothesis.

This study coupled the green water and blue water accounting with the existing standard Budyko framework and Fu's 1-parameter Budyko framework to diagnose the basin hydrological behavior. Both Budyko frameworks were employed to determine green water consumption (ETGreen) and blue water consumption (ETBlue) which, in turn, were used to map the blue water index (BWI) hotspots and green water index (GWI) bright spots. The relative contributions of green water and blue water were quantified for sustaining water and food security. A new methodology is proposed using BWI and GWI for partitioning the Gross Primary Production (GPP) and Water Use Efficiency (WUE) into GPPBlue, GPPGreen and WUEBlue and WUEGreen. The methodology was applied to five sub-basins of the Central Godavari River Basin (CGRB): Purna, Dhalegaon, GR Bridge, Yeli and Delta. Results showed that all five basins exhibited larger deviations from the theoretical Budyko curve of Fu's 1-parameter Budyko framework than did the standard Budyko framework and the Dhalegaon basin showed the largest deviations. The partitioning of GPP and WUE by the proposed methodology showed that the proportion of GPPGreen to the total GPP was much higher than that of the GPPBlue. Similarly, the proportion of WUEGreen to WUE was more than that of WUEBlue. The mapping of GPPBlue and GPPGreen, and WUEBlue and WUEGreen showed that the Delta and Yeli basins had the highest values of both GPPGreen & GPPBlue and WUEBlue and WUEGreen (bright spot basins) and the Dhalegaon and parts of GR Bridge basin had the lowest values (hot spot basins). The proposed partitioning of GPP and WUE will help identify the relative contributions of green water and blue water (for managing agricultural waters) and formulate agronomical and engineering practices for stakeholders and policy makers for increasing the overall WUE and GPP to sustain water and food security.

The virtual water content of major grain crops and virtual water flows between regions in China.

BACKGROUND: The disproportionate distribution of arable land and water resources has become a bottleneck for guaranteeing food security in China. Virtual water and virtual water trade theory have provided a potential solution to improve water resources management in agriculture and alleviate water crises in water-scarce regions. The present study evaluates the green and blue virtual water content of wheat, maize and rice at the regional scale in China. It then assesses the water-saving benefits of virtual water flows related to the transfer of the three crops between regions. RESULTS: The national average virtual water content of wheat, maize and rice were 1071 m(3) per ton (50.98% green water, 49.02% blue water ), 830 m(3) per ton (76.27% green water, 23.73% blue water) and 1294 m(3) per ton (61.90% green water, 38.10% blue water), respectively. With the regional transfer of wheat, maize and rice, virtual water flows reached 30.08 Gm(3) (59.91% green water, 40.09% blue water). Meanwhile, China saved 11.47 Gm(3) green water, while it consumed 7.84 Gm(3) more blue water than with a no-grain transfer scenario in 2009. CONCLUSION: In order to guarantee food security in China, the government should improve water productivity (reduce virtual water content of crops) during the grain production process. Meanwhile, under the preconditions of economic feasibility and land-water resources availability, China should guarantee the grain-sown area in southern regions for taking full advantage of green water resources and to alleviate the pressure on water resources.

U.S. Blue Water Navy Veterans of the Vietnam War: Comparisons from the Vietnam Era Health Retrospective Observational Study (VE-HEROeS).

Background: US Vietnam War Blue Water Navy veterans (BWN) conducted military operations on Vietnam's offshore waters and likely experienced various war-related exposures. The overall health of the BWN has never been systematically studied. Purpose: Describe and compare BWN's health with other servicemembers and non-veterans of the Vietnam era. Materials and methods: Survey of 45 067 randomly selected US Vietnam War theatre and non-theatre veterans and 6885 non-veterans. Results: For 22 646 male respondents, self-reported health was contrasted by veteran status defined as BWN (n=985), theatre veterans (n=6717), non-theatre veterans (n=10 698) and non-veterans (n=4246). Exposure was service in the Vietnam War theatre. Collected were demographics, military service characteristics, lifestyle factors and health conditions. Adjusted odds ratios (aOR) were calculated using multivariable logistic regression. Controlling for cigarette smoking and other covariates, respiratory cancer risk was highest in BWN vs other veterans (theatre: aOR 1.65; 95% CI 1.09, 2.50; non-theatre: aOR 1.77; 1.13, 2.77) and to non-veterans (aOR 1.78; 1.15, 2.74). Other findings showed BWN's health risks between theatre and non-theatre veterans. Conclusion: There was a higher risk for respiratory cancers in BWN. Other risks were less than theatre veterans but greater than non-theatre or non-veterans, indicating a potential role of military exposures in BWN's health.

Environmental impact and nutrient adequacy of derived dietary patterns in Vietnam.

Rationale and objective: Improving diet quality while decreasing environmental impacts is an important challenge for a healthy and sustainable food system. Therefore, this study aims to analyze the most common dietary patterns per female household member and explore the diet quality and environmental impacts of these patterns. Methodology: The nationally representative General Nutrition Survey of 2009-2010 (n = 8,225 households) was used to derive dietary patterns using principal component analysis (PCA) based on 18 food groups as input variables. Quintiles of the highest adherence (Q5) and lowest adherence (Q1) were generated based on the factor score of each dietary pattern. Nutrient adequacy and dietary diversity scores (DDS) were calculated to measure diet quality, and greenhouse gas emission (GHGE) and blue water use (BWU) were selected as environmental impact indicators. Results: Using PCA, three distinct dietary patterns were identified: an Omnivorous, Traditional, and Pescatarian pattern. Compared to the Traditional pattern, the Omnivorous and Pescatarian patterns (Q5s) were associated with a higher nutrient adequacy, with mean probability of adequacy of 0.51 in both patterns, compared to 0.45 in the Traditional pattern. However, environmental impacts in terms of GHGE and BWU per 2,000 kcal were considerably higher in the Omnivorous pattern (6.14 kg CO2-eq. and 0.15 m3/kg) compared to all other pattern's Q5s. The GHGE was lowest in the Traditional pattern (4.18 kg CO2-eq.) and the Pescatarian pattern has the lowest BWU (0.12 m3/kg). Conclusion: Despite that diet quality was slightly better in all three patterns compared to the average diet of the total population, environmental impact was also higher. Therefore, future research is needed to develop a more optimal diet that considers both diet quality and environmental impact to explore the trade-offs between diet quality and environmental impact.

Comprehensive analysis of water resources from the perspective of water footprint and water ecological footprint: a case study from Anyang City, China.

Agriculture is the largest freshwater consumer, accounting for ~ 70% of global freshwater consumption. The agricultural water footprint (WF) and water resources ecological footprint (EFw) are used to describe the ecological environment and socioeconomic functions of water resources. Anyang in the North China Plain is a typical area with freshwater shortage and was selected as a study area to estimate water consumption by agriculture. We estimated the spatiotemporal variation of green, blue, and grey WF of five crops in Anyang during 1990-2018 based on the WF theory, EFw, and water resources carrying capacity (ECw) methods. To analyze the EFw of specific crops, we developed the framework between agricultural WF and EFw, and quantified the EFw of specific crops. The results show that the WFgreen, WFblue, and WFgrey of Anyang increased from 1188, 1560, and 511 million m3 in 1990 to 1440, 1736, and 1010 million m3 in 2018, respectively, mainly owing to the increase of cultivated area and amount of agricultural nitrogen. Winter wheat and maize were the two leading crops in both green and blue water consumption, taking 31.35 and 55.25% of the total WFgreen, and 71.32 and 22.52% of the total WFblue, respectively. The average unit mass WFgreen and WFblue of crops showed a reducing trend during 1990-2018 because of the urbanization of farmland and the increase of crop yields. Both ECw and water ecological deficit per capital in Anyang decreased. Anyang has been in a state of water ecological deficit since 2000. The results imply that Anyang has been importing a large amount of water from other areas for its consumption since 2000. This study is expected to contribute to agricultural water management by providing suitable information to policy-makers. Furthermore, the results of this study indicate that it is urgent to make strict water resource management and water pollution prevention measures to improve the water use efficiency in Anyang and to ease the pressure on water scarcity.

Assessment of the regional agricultural water-land Nexus in China: A green-blue water perspective.

An appropriate agricultural water-land nexus can help to effectively take advantage of limited water and land resources, which is of great significance for guaranteeing food security. An R index was proposed to evaluate the regional agricultural water-land nexus from a green-blue water perspective in the current paper. The effects of irrigation on the agricultural water-land nexus were revealed for the first time based on this index in evaluations of all (Rt) and irrigated (Ri) arable land in the 31 provinces, autonomous regions and municipalities (PAMs) of China during 1999-2018. The national annual average values of Rt and Ri were 1.94 and 3.55 m3/m2, respectively; the former was steady during the observed period, while the latter showed a significant decreasing trend (P < 0.01) from 4.35 m3/m2 in 1999 to 2.66 m3/m2 in 2018. The values of both Rt and Ri values in South China were higher than those in North China. The maximum values of Rt and Ri appeared in Xizang (Rt = 99.15 m3/m2; Ri = 201.99 m3/m2), while the minimum values occurred in Ningxia (Rt = 0.30 m3/m2; Ri = 0.44 m3/m2). The Gini coefficient for Ri (Gi) in each year was higher than that for Rt (Gt), demonstrating that the agricultural water-land nexus in irrigated arable land was highly imbalanced during the last two decades. From the perspective of the equitable distribution of irrigation water, irrigation facilities should be developed in the Southeast and Southwest PAMs to improve the effective irrigation rate. In addition, the government should simultaneously implement water transfer plans to reduce the agricultural water pressure in the PAMs in the North China Plain and Northeast China.

Water footprint of lemon production in Argentina.

This work comes to fill a knowledge gap regarding the sustainability of the lemon industry. The motivation is the prominent role of the citrus sector in the economy of the northwest of Argentina and in the world: Argentina is the eighth largest producer of fresh citrus fruits, one of the four leading lemon-producing countries and the world's first lemon processor. A water footprint study is conducted to obtain relevant information on the water consumption and degradation associated with citrus production, according to the Water Footprint Network guidelines. A remarkable aspect is that most data used come mainly from actual practices and sources considering daily weather data of seven weather stations from 2012 to 2018. The green, blue and grey water footprints linked to the primary production of lemons are evaluated every year. The water footprint is distributed approximately in 69% (234 m3t-1) green, 8% (30 m3t-1) blue and 23% (82 m3t-1) grey. In addition, the Available Water Remaining (AWARE) indicator is used for outlining the blue water sustainability, resulting in a potential for blue water deprivation of 102 m3 world eq. per tonne of harvested lemons. This work is expected to serve as a baseline to provide diagnosis and improvement opportunities in the lemon sector for public and private stakeholders.

Domestic plant food loss and waste in the United States: Environmental footprints and mitigation strategies.

The United States (U.S.) aims to reduce half of food loss and waste (FLW) by 2030. To achieve this goal, the public, academic, and political attentions on FLW have been increasing, and a series of actions have been implemented. However, the actions lack consideration on the categorical priority of FLW mitigation in relation to environmental footprints. In this article, we compare the FLW of three main plant food categories (i.e., grains, vegetables, and fruits) and their water and carbon footprints during 1970-2017. The vegetable FLW doubled during the period, reaching 3.39 × 1010 kg in 2017, which was 5- and 2-fold higher than the FLW of grains and fruits, respectively. The FLW of vegetables, grains, and fruits contributed 29%, 47%, and 24% to the total blue water wasted through FLW. The total carbon dioxide emissions generated by plant FLW were contributed by vegetables with 50%, grains with 31%, and fruits with 19%. Canonical correspondence analysis indicates that vegetable FLW had a higher positive correlation with urbanization, household incomes, gross domestic product, and high-income population than grain FLW, whereas fruit FLW was not influenced by these socioeconomic factors. Therefore, we suggest that the FLW mitigation should be prioritized on vegetables. Specific strategies include local food sourcing, shortening food miles, building food belts, and developing controlled-environment agriculture. Our data-based comparisons provide valuable insights into food policy improvement for achieving the 2030 reduction goal of the U.S., but the insights could be improved by considering the influences of foods imported from other nations.

Limited water scarcity mitigation by expanded interbasin physical and virtual water diversions with uneven economic value added in China.

Interbasin water diversion projects and virtual water transfers embedded in exchanged goods and services are two effective solutions to water deficits. However, the associated real responses in water quantity and quality scarcities and the economic efficiencies remain unclear. Here, we tracked the blue water scarcities, water pollution levels, and economic value added through interbasin physical and virtual water diversions across nine river basins by sector in China from 2007 to 2015. The total national blue and grey water footprints were 365 Gm3yr-1 and 592 Gm3 yr-1, in which the Yangtze River basin accounts the most for 32 % and 37 %, respectively, by 2015. The physical water diversions increased by 52 % to 16.9 Gm3yr-1. The blue virtual water transfers increased by 24 % to 176 Gm3yr-1, whereas the grey virtual water transfers decreased by 10 % to 266 Gm3yr-1. Agriculture related interbasin virtual water flows showed opposite directions to those driven by the industry sector. Although with uneven value added while growing, limited effects mitigated water quantity and quality stresses, especially in the drier Yellow, Northwest, and Hai River basins where the capital is located. Half of the basins had low and declining synergy scores, suggesting an urgent need to achieve synergies between resources, the environment, and the economy across basins.

Life cycle water footprint analysis for second-generation biobutanol.

Water is essential in conversion of crop to bioenergy. Therefore, it is important to carefully evaluate the impact of bioenergy technology on water source. Life cycle water footprints of biobutanol from wheat straw, corn grain and corn stover are analyzed in this study according to the characteristics of crop growing and climate conditions. The results show that life cycle water footprints of biobutanol from wheat straw, corn grain and corn stover are 271, 108 and 240 L H2O/MJ biobutanol, respectively. Life cycle water footprints of the crop production stage for wheat straw, corn grain and corn stover are 269.89, 107.84 and 238.95 L H2O/MJ biobutanol, respectively. Owing to the use of fertilizer in the crop production stage, gray water footprint of wheat straw, corn grain and corn stover accounts for 91.08%, 86.65% and 86.40% of the life cycle water footprint, respectively.