Transitions to freshwater sustainability

Empowering ultrathin polyamide membranes at the water-energy nexus: strategies, limitations, and future perspectives

Membrane-based separation is one of the most energy-efficient methods to meet the growing need for a significant amount of fresh water. It is also well-known for its applications in water treatment, desalination, solvent recycling, and environmental remediation. Most typical membranes used for separation-based applications are thin-film composite membranes created using polymers, featuring a top selective layer generated by employing the interfacial polymerization technique at an aqueous-organic interface. In the last decade, various manufacturing techniques have been developed in order to create high-specification membranes. Among them, the creation of ultrathin polyamide membranes has shown enormous potential for achieving a significant increase in the water permeation rate, translating into major energy savings in various applications. However, this great potential of ultrathin membranes is greatly hindered by undesired transport phenomena such as the geometry-induced "funnel effect" arising from the substrate membrane, severely limiting the actual permeation rate. As a result, the separation capability of ultrathin membranes is still not fully unleashed or understood, and a critical assessment of their limitations and potential solutions for future studies is still lacking. Here, we provide a summary of the latest developments in the design of ultrathin polyamide membranes, which have been achieved by controlling the interfacial polymerization process and utilizing a number of novel manufacturing processes for ionic and molecular separations. Next, an overview of the in-depth assessment of their limitations resulting from the substrate membrane, along with potential solutions and future perspectives will be covered in this review.

The Urban Environment and Cardiometabolic Health

Urban environments contribute substantially to the rising burden of cardiometabolic diseases worldwide. Cities are complex adaptive systems that continually exchange resources, shaping exposures relevant to human health such as air pollution, noise, and chemical exposures. In addition, urban infrastructure and provisioning systems influence multiple domains of health risk, including behaviors, psychological stress, pollution, and nutrition through various pathways (eg, physical inactivity, air pollution, noise, heat stress, food systems, the availability of green space, and contaminant exposures). Beyond cardiometabolic health, city design may also affect climate change through energy and material consumption that share many of the same drivers with cardiometabolic diseases. Integrated spatial planning focusing on developing sustainable compact cities could simultaneously create heart-healthy and environmentally healthy city designs. This article reviews current evidence on the associations between the urban exposome (totality of exposures a person experiences, including environmental, occupational, lifestyle, social, and psychological factors) and cardiometabolic diseases within a systems science framework, and examines urban planning principles (eg, connectivity, density, diversity of land use, destination accessibility, and distance to transit). We highlight critical knowledge gaps regarding built-environment feature thresholds for optimizing cardiometabolic health outcomes. Last, we discuss emerging models and metrics to align urban development with the dual goals of mitigating cardiometabolic diseases while reducing climate change through cross-sector collaboration, governance, and community engagement. This review demonstrates that cities represent crucial settings for implementing policies and interventions to simultaneously tackle the global epidemics of cardiovascular disease and climate change.

Toward Heart-Healthy and Sustainable Cities: A Policy Statement From the American Heart Association

Nearly 56% of the global population lives in cities, with this number expected to increase to 6.6 billion or >70% of the world's population by 2050. Given that cardiometabolic diseases are the leading causes of morbidity and mortality in people living in urban areas, transforming cities and urban provisioning systems (or urban systems) toward health, equity, and economic productivity can enable the dual attainment of climate and health goals. Seven urban provisioning systems that provide food, energy, mobility-connectivity, housing, green infrastructure, water management, and waste management lie at the core of human health, well-being, and sustainability. These provisioning systems transcend city boundaries (eg, demand for food, water, or energy is met by transboundary supply); thus, transforming the entire system is a larger construct than local urban environments. Poorly designed urban provisioning systems are starkly evident worldwide, resulting in unprecedented exposures to adverse cardiometabolic risk factors, including limited physical activity, lack of access to heart-healthy diets, and reduced access to greenery and beneficial social interactions. Transforming urban systems with a cardiometabolic health-first approach could be accomplished through integrated spatial planning, along with addressing current gaps in key urban provisioning systems. Such an approach will help mitigate undesirable environmental exposures and improve cardiovascular and metabolic health while improving planetary health. The purposes of this American Heart Association policy statement are to present a conceptual framework, summarize the evidence base, and outline policy principles for transforming key urban provisioning systems to heart-health and sustainability outcomes.

Net benefit of smaller human populations to environmental integrity and individual health and wellbeing

Introduction

The global human population is still growing such that our collective enterprise is driving environmental catastrophe. Despite a decline in average population growth rate, we are still experiencing the highest annual increase of global human population size in the history of our species-averaging an additional 84 million people per year since 1990. No review to date has accumulated the available evidence describing the associations between increasing population and environmental decline, nor solutions for mitigating the problems arising.

Methods

We summarize the available evidence of the relationships between human population size and growth and environmental integrity, human prosperity and wellbeing, and climate change. We used PubMed, Google Scholar, and Web of Science to identify all relevant peer-reviewed and gray-literature sources examining the consequences of human population size and growth on the biosphere. We reviewed papers describing and quantifying the risks associated with population growth, especially relating to climate change.

Results

These risks are global in scale, such as greenhouse-gas emissions, climate disruption, pollution, loss of biodiversity, and spread of disease-all potentially catastrophic for human standards of living, health, and general wellbeing. The trends increasing the risks of global population growth are country development, demographics, maternal education, access to family planning, and child and maternal health.

Conclusion

Support for nations still going through a demographic transition is required to ensure progress occurs within planetary boundaries and promotes equity and human rights. Ensuring the wellbeing for all under this aim itself will lower population growth and further promote environmental sustainability.

Contact-Electro-Catalysis-Assisted Separation via a Dancing PTFE Membrane for Fouling Control

Advanced oxidization processes (AOPs) offer promising solutions for addressing the fouling issues in membrane separation systems. However, the high energy requirements for electrical or light power in the AOPs can be a drawback. In this study, we present a contact-electro-catalysis (CEC)-based approach for controlling membrane fouling, which is stimulated by mild ultrasonic irradiation. During this process, electrons are transferred between a dancing polytetrafluoroethylene membrane and water or oxygen molecules, resulting in the formation of free radicals •OH and •O2-. These free radicals are capable of degrading or inactivating foulants, eliminating the need for additional chemical cleaners, secondary waste disposal, or external stimuli. Furthermore, the time-dependent voltage spikes/oscillations (peak, +7.8/-8.2 V) generate a nonuniform electric field that drives dielectrophoresis, effectively keeping contaminants away from the membrane surface and further enhancing the antifouling performance of the dancing membrane. Therefore, the CEC-assisted membrane separation system offers a green and effective strategy for controlling membrane fouling through mild mechanical stimulation.

Envisaged methodologies for sustainable food labelling policies might worsen water scarcity

To reduce the current billions of people facing water scarcity, which is a dedicated Sustainable Development Goal (SDG) target, different actions and measures are required. This includes food labelling which accounts for water scarcity, to help consumers make informed choices when purchasing food products. The European Commission is considering the proposal of a "Sustainable food labelling framework" in the last quartal of 2023, within its ambitious Farm to Fork strategy. Implementing such a food label in the EU has a potential reach of 447 million consumers. Most prominent label candidate is its own developed PEF (Product Environmental Footprint), a tool already implemented by some retailers in the EU. However, this paper argues that the category water scarcity in the PEF has two major flaws. First, it does not account for water efficiency of a product, which is essential to solve global water stress. Second, the spatial resolution for water stress is much too coarse. The current PEF tool makes comparisons between products useless and even misleading. Its use might worsen global water scarcity, as it provides producers and consumers the wrong incentives. Urgent revision of the category water stress in the PEF is required. This can be done by using the indicators water stress and water efficiency in a complementary way, as well as using the most detailed spatial resolution science can provide.

Influence of respondents' Differentiation of subjective response on water knowledge stock test scale: Evaluation based on two-parameter-multidimensional IRT model

Insufficient awareness of water issues is a crucial bottleneck restricting the sustainable utilization of water resources. To accurately measure citizens' water knowledge stock and overcome the differences between scales and respondents' characteristic levels on test results, the research focuses on developing and evaluating water knowledge stock test scales. The mechanism for identifying indicators is designed based on the grounded theory, and as a result, the water knowledge stock test indicator system is derived. The data was collected by the form of survey questionnaire developed with the test indicator system. A two-parameter multidimensional item response theoretical model is constructed based on item parameter estimation, data model fitting, and item information function. The survey data and optimization model are used to optimize the water knowledge stock test scale and verify the fitting degree with the characteristics of the respondents. The test information function and standard error function indicate that the scale is most informative for individuals with characteristic levels ranging from -2 to 3, resulting in a highly reliable test effect. The research has established a measurement indicator system, methodology, and presented results that serve as a foundation for measuring the stock of water knowledge.

Linking ecosystem service flow to water-related ecological security pattern: A methodological approach applied to a coastal province of China

Water security is a critical concern due to intensifying anthropogenic activities and climate change. Delineating a water-related ecological security pattern can help to optimize spatial configuration, which in turn can inform sustainable water management. However, the methodology remains unclear. In this study, we developed a framework linking ecosystem service flow to water-related ecological security pattern; hence, we identified the sources, sinks, key corridors, and vulnerable nodes in Fujian Province, China. Our results revealed that the sources were located inland at high altitudes with a decreasing area trend in the south and an increasing area trend in the north, whereas the sinks were spread in coastal areas and exhibited a decreasing trend with relatively stable spatial distribution. The water-related ecological security has degraded as represented by a decreasing ecological supply-demand ratio over the last 30 years. Key corridors were identified in 17.12% of the rivers, and 22.5% of the vulnerable nodes were recognized as early warning nodes. Climate variability affected source distribution, while anthropogenic activities drove sink dynamics. These findings have important implications including landscape pattern planning and sustainable water management in the context of accelerated land use/cover and climate changes.

Predictions of household water affordability under conditions of climate change, demographic growth, and fresh groundwater depletion in a southwest US city indicate increasing burdens on the poor

Reduced river flows and groundwater depletion as a result of climate change and population growth have increased the effort and difficulty accessing and processing water. In turn, residential water costs from municipal utilities are predicted to rise to unaffordable rates for poor residential water customers. Building on a regional conjunctive use model with future climate scenarios and 50-year future water supply plans, our study communicates the effects of climate change on poor people in El Paso, Texas, as water becomes more difficult and expensive to obtain in future years. Four scenarios for future water supply and future water costs were delineated based on expected impacts of climate change and groundwater depletion. Residential water use was calculated by census tract in El Paso, using basic needs indoor water use and evaporative cooling use as determinants of household water consumption. Based on household size and income data from the US Census, fraction of household income spent on water was determined. Results reveal that in the future, basic water supply will be a significant burden for 40% of all households in El Paso. Impacts are geographically concentrated in poor census tracts. Our study revealed that negative impacts from water resource depletion and increasing populations in El Paso will lead to costly and difficult water for El Paso water users. We provide an example of how to connect future resource scenarios, including those affected by climate change, to challenges of affordability for vulnerable consumers.

Understanding the accuracy of modelled changes in freshwater provision over time

Accurate modelling of changes in freshwater supplies is critical in an era of increasing human demand, and changes in land use and climate. However, there are concerns that current landscape-scale models do not sufficiently capture catchment-level changes, whilst large-scale comparisons of empirical and simulated water yield changes are lacking. Here we modelled annual water yield in two time periods (1: 1985-1994 and 2: 2008-2017) across 81 catchments in England and validated against empirical data. Our objectives were to i) investigate whether modelling absolute or relative change in water yield is more accurate and ii) determine which predictors have the greatest impact on model accuracy. We used the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) Annual Water Yield model. In this study, absolute values refer to volumetric units of million cubic metres per year (Mm³/y), either at the catchment or hectare level. Modelled annual yields showed high accuracy as indicated by the low Mean Absolute Deviation (MAD, based on normalised data, 0 is high and 1 is low accuracy) at the catchment (1: 0.013 ± 0.019, 2: 0.012 ± 0.020) and hectare scales (1: 0.03 ± 0.030, 2: 0.030 ± 0.025). But accuracy of modelled absolute change in water yield showed a more moderate fit on both the catchment (MAD = 0.055 ± 0.065) and hectare (MAD = 0.105 ± 0.089) scales. Relative change had lower accuracy (MAD = 0.189 ± 0.135). Anthropogenic modifications to the hydrological system, including water abstraction contributed significantly to the inaccuracy of change values at the catchment and hectare scales. Quantification of changes in freshwater provision can be more accurately articulated using absolute values rather than using relative values. Absolute values can provide clearer guidance for mitigation measures related to human consumption. Accuracy of modelled change is related to different aspects of human consumption, suggesting anthropogenic impacts are critically important to consider when modelling water yield.

A Framework to Support the Selection of an Appropriate Water Allocation Planning and Decision Support Scheme

Water is becoming a scarce resource in many parts of the world, leading to increased competition amongst water users. Optimized water allocation is increasingly important to balance the growing demand for water and the limited supply of accessible clean water. The literature on water allocation schemes and decision support systems, developed for application in specific water management areas or watersheds, was critically reviewed. Although the literature is rich in studies on the application of a broad range of water allocation schemes, there is a lack of information available on the methodology and process of selecting the most applicable scheme that balances the local realities and requirements of stakeholders while considering the local context with regard to the economic, social and environmental impact of water usage. In this article, a framework is presented that water management practitioners can use to select applicable water allocation planning schemes and associated decision support systems based on the characteristics and requirements of the specific water management situation. The framework was used to analyse the water supply situation in South Africa (SA), taking broader factors into account. Based on this, a generic conceptualized water allocation planning and decision support framework for a typical SA water management area is proposed.

Can Water Price Improve Water Productivity? A Water-Economic-Model-Based Study in Heihe River Basin, China

Water demand management through price and market mechanisms is crucial for agricultural water management. However, how to set an appropriate agricultural water price remains unclear due to the uncertainty regarding the response of water demand to price changes and the complexity of the hydro-economic system. Thus, this study developed a water-economic model to examine both issues in the Heihe River Basin. The empirical results revealed that the basin’s agricultural water is currently price-inelastic, with a value of −0.26, but that at 0.27 yuan/m3, elasticity is gained. At this tipping point, water demand and economic output decline by up to 10.2% and 1.6%, respectively, while water productivity increases by 7.2%. It is noteworthy that the reallocation of water and land resources from agricultural sectors to non-agricultural sectors facilitated by a water price change is the main contributor towards water productivity improvement. This signifies the importance of managing water and land resources in an integrated framework to improve water productivity in the future. Our study contributes to the literature by suggesting that future policies for water-demand management should consider pricing that encourages water saving and the reallocation of water resources to high-value uses in order to increase water productivity.

Kindlin-2 promotes Src-mediated tyrosine phosphorylation of androgen receptor and contributes to breast cancer progression

Androgen receptor (AR) signaling plays important roles in breast cancer progression. We show here that Kindlin-2, a focal adhesion protein, is critically involved in the promotion of AR signaling and breast cancer progression. Kindlin-2 physically associates with AR and Src through its two neighboring domains, namely F1 and F0 domains, resulting in formation of a Kindlin-2-AR-Src supramolecular complex and consequently facilitating Src-mediated AR Tyr-534 phosphorylation and signaling. Depletion of Kindlin-2 was sufficient to suppress Src-mediated AR Tyr-534 phosphorylation and signaling, resulting in diminished breast cancer cell proliferation and migration. Re-expression of wild-type Kindlin-2, but not AR-binding-defective or Src-binding-defective mutant forms of Kindlin-2, in Kindlin-2-deficient cells restored AR Tyr-534 phosphorylation, signaling, breast cancer cell proliferation and migration. Furthermore, re-introduction of phosphor-mimic mutant AR-Y534D, but not wild-type AR reversed Kindlin-2 deficiency-induced inhibition of AR signaling and breast cancer progression. Finally, using a genetic knockout strategy, we show that ablation of Kindlin-2 from mammary tumors in mouse significantly reduced AR Tyr-534 phosphorylation, breast tumor progression and metastasis in vivo. Our results suggest a critical role of Kindlin-2 in promoting breast cancer progression and shed light on the molecular mechanism through which it functions in this process.

National water shortage for low to high environmental flow protection

Global freshwater biodiversity has been decreasing rapidly, requiring the restoration and maintenance of environmental flows (EFs) in streams and rivers. EFs provide many ecosystem services that benefit humans. Reserving such EFs for aquatic ecosystems, implies less renewable water availability for direct human water use such as agriculture, industry, cities and energy. Here we show that, depending on the level of EF protection, global annual renewable water availability for humans decreases between 41 and 80% compared to when not reserving EFs. With low EF protection, currently 53 countries experience different levels of water shortage, which increases to 101 countries for high EF protection. Countries will carefully have to balance the amount of water allocated to humans and the environment.

Metal–organic-framework-based photocatalysts for microorganism inactivation: a review

A metal–organic framework (MOF) is a porous coordination material composed of multidentate organic ligands and metal ions or metal clusters.

Freshwater availability status across countries for human and ecosystem needs

Water demand is expected to continue rising to support growing population, particularly in water-stressed countries and regions. Amid competitive water needs for agricultural, domestic, and industrial sectors, water allocations for environmental requirements are critical to ensure the sustainability of the ecosystems. This study takes stock of water availability trends per capita across countries and proposes a water scarcity indicator to quantify the amount of water available for agricultural, domestic, and industrial activities after the needs of freshwater ecosystems (environmental flow requirements, EFR) are ideally fulfilled. The study reveals that by 2050, 87 out of 180 countries will have annual renewable water resources (ARWR) per capita below 1700 m³/year. The number of countries with absolute water scarcity - ARWR per capita below 500 m³/year is projected to increase from 25 in 2015 to 45 by 2050. Population growth is projected to cause a sharp decline in water availability in many low-income and lower-middle-income countries, while economic development will push water use upwards, making the water supply gap more complicated and challenging to address. After the Middle East and North Africa region, Sub-Saharan Africa is expected to become the next hotspot of water scarcity along with several countries from Asia. In response, water-scarce countries need to promote water conservation, water recycling, and reuse; ensure sustainable water resources augmentation via harnessing the potential of unconventional water resources; support productivity enhancement of underperforming land and water resources; and address challenges beyond technical solutions. Pertinent political agenda and associated public policies, supportive institutions, institutional collaborations, and skilled professionals would be the key to ensure sufficient water supply for human use and ecosystems.

The legacy of large dams in the United States

The sustainability of large dams has been questioned on several grounds. One aspect that has been less explored is that the development of dams and reservoirs often enables agricultural expansion and urban growth, which in turn increase water consumption. As such, dam development influences, while being influenced by, the spatial and temporal distribution of both supply and demand of water resources. In this paper, we explore the interplay between large dams, patterns of population growth and agricultural expansion in the United States over the past two centuries. Based on a large-scale analysis of spatial and temporal trends, we identify three distinct phases, in which different processes dominated the interplay. Then, we focus on agricultural water use in the Southwest region (Arizona, California and Nevada) and explore chicken-and-egg dynamics where water supply partly meets and partly fuels water demand. Lastly, we show that the legacy of dams in the United States consists of a lock-in condition characterized by high levels of water consumption, especially in the Southwest, which leads to severe water crises and groundwater overexploitation when droughts occur.

[Advances in high-throughput proteomic analysis]

基于质谱的蛋白质组学技术已经日趋成熟,可以对细胞和组织中的成千上万种蛋白质进行全面的定性和定量分析,逐步实现“深度覆盖”。随着生物医学日益增长的大队列蛋白质组学分析需求,如何在保持较为理想的覆盖深度下实现短时间、快速的“高通量”蛋白质组学分析已成为当前亟需解决的关键问题之一。常规的蛋白质组学分析流程通常包括样品前处理、色谱分离、质谱检测和数据分析。该文从以上4个方面展开介绍近10年以来高通量蛋白质组学分析技术取得的一系列研究进展,主要包括:(1)基于高通量、自动化移液工作站的蛋白质组样品前处理方法;(2)基于微升流速液相色谱与质谱联用的高通量蛋白质组检测方法;(3)利用灵敏度高、扫描速度快的质谱仪实现短色谱梯度分离下蛋白质组深度覆盖的分析方法;(4)基于人工智能、深度神经网络、机器学习等的蛋白质组学大数据分析方法。此外,对高通量蛋白质组学面临的挑战及其发展进行展望。总而言之,预期在不久的将来高通量蛋白质组学技术将会逐步“落地转化”,成为大队列蛋白质组学分析的利器。

Gains or losses? A quantitative estimation of environmental and economic effects of an ecological compensation policy

Ecological compensation is an innovative and effective tool to explore the coordinated development of socioeconomic prosperity and ecological protection, especially for a watershed crossing different regions. It converts the externalities of ecosystem services into practical financial incentives for local stakeholders. This empirical study applies a quantitative policy evaluation approach to evaluate the environmental and economic effects of an ecological compensation policy, using the paddy land-to-dry land (PLDL) program implemented in China's Miyun Reservoir watershed as an example. The study is based on responses to a 2017 questionnaire regarding agricultural production inputs and outputs administered to 269 households in Hebei Province, where the PLDL program has been operational for over 10 yr. The results show that the program has reduced nitrogen usage by 24% on average in 2017 and decreased the total nitrogen emission load by 16.98 tons for the entire case area, which accounts for approximately 18.6% of the total nitrogen load reduction of the Miyun Reservoir basin. However, the upstream households involved in this program have experienced agricultural income losses higher than that allowed for by the current compensation criterion. Therefore, this paper discusses the factors that should be considered in the process of determining ecological compensation criteria. In particular, the paper proposes a differential compensation scheme based on the environmental effect at the individual level to avoid a standard payment for all households irrespective of their different contributions. This differential compensation payment scheme facilitates the fair treatment of environmental contributors and maximizes environmental benefits through an equitable allocation of limited ecological compensation funds. This study serves as a theoretical and practical reference for further improvement of the current ecological compensation policy in China. The study also sheds light on practices for estimating ecological compensation criteria and formulating ecological compensation policies for other regions or countries in the future.

A coupled human-natural system analysis of freshwater security under climate and population change

Jordan is facing an unfolding water crisis, exacerbated by climate change and conflict-induced refugee influxes. We present a freshwater security analysis for the country, enabled by an integrated systems model that combines simulation of Jordan’s natural and built water environment with thousands of representative human agents determining water allocation and use decisions. Our analysis points to severe, potentially destabilizing, declines in Jordan’s freshwater security. Without intervening measures, over 90% of Jordan’s low-income population will be experiencing critical water insecurity by the end of the century. To gain a foothold on its water future, Jordan must enact an ambitious portfolio of interventions that span supply- and demand-side measures, including large-scale desalinization and comprehensive water-sector reform.

Limited water availability, population growth, and climate change have resulted in freshwater crises in many countries. Jordan’s situation is emblematic, compounded by conflict-induced population shocks. Integrating knowledge across hydrology, climatology, agriculture, political science, geography, and economics, we present the Jordan Water Model, a nationwide coupled human–natural-engineered systems model that is used to evaluate Jordan’s freshwater security under climate and socioeconomic changes. The complex systems model simulates the trajectory of Jordan’s water system, representing dynamic interactions between a hierarchy of actors and the natural and engineered water environment. A multiagent modeling approach enables the quantification of impacts at the level of thousands of representative agents across sectors, allowing for the evaluation of both systemwide and distributional outcomes translated into a suite of water-security metrics (vulnerability, equity, shortage duration, and economic well-being). Model results indicate severe, potentially destabilizing, declines in freshwater security. Per capita water availability decreases by approximately 50% by the end of the century. Without intervening measures, >90% of the low-income household population experiences critical insecurity by the end of the century, receiving <40 L per capita per day. Widening disparity in freshwater use, lengthening shortage durations, and declining economic welfare are prevalent across narratives. To gain a foothold on its freshwater future, Jordan must enact a sweeping portfolio of ambitious interventions that include large-scale desalinization and comprehensive water sector reform, with model results revealing exponential improvements in water security through the coordination of supply- and demand-side measures.

Changes in supply and demand mediate the effects of land-use change on freshwater ecosystem services flows

Land-use change alters the dynamics of freshwater ecosystem services flows by affecting both service supply (by influencing hydrological processes and runoff) and demand (via changes in human water use). However, few studies have considered the wide range of effects of land-use change on freshwater ecosystem services' flows. In this study, we distinguished the impacts of changing water supply and demand in the Aojiang River watershed, Fujian Province, China, an important water resource for more than seven million people. Rapid urbanization between 1991 and 2015 led to a minor increase of 2.5% in the supply of freshwater ecosystem services. However, demand increased by 96.3%, leading to a 25.7% overall decrease in freshwater ecosystem services flows. Downstream demand for freshwater increased substantially due to large shifts in agricultural, urban, and industrial activities. Our analysis provides detailed information on freshwater ecosystem services flows from supply to beneficiaries within a watershed, thus facilitating integrated watershed management and decision making. This study demonstrates how land-use change and ecosystem services' flows can be integrated both at local and regional scales for land-use management, water reallocation, and ecological compensation, thus promoting the sustainability of freshwater ecosystems.

Is there enough water? How bearish and bullish outlooks are linked to decision maker perspectives on environmental flows

Policies that mandate environmental flows (e-flows) can be powerful tools for freshwater conservation, but implementation of these policies faces many hurdles. To better understand these challenges, we explored two key questions: (1) What additional data are needed to implement e-flows? and (2) What are the major socio-political barriers to implementing e-flows? We surveyed water and natural resource decision makers in the semi-arid Red River basin, Texas-Oklahoma, USA, and used social network analysis to analyze their communication patterns. Most respondents agreed that e-flows can provide important benefits and identified the same data needs. However, respondents sharply in their beliefs on other issues, and a clustering analysis revealed two distinct groups of decision makers. One cluster of decision makers tended to be bearish, or pessimistic, and believed that: current flow conditions are not adequate, there are many serious socio-political barriers to implementation, water conflicts will likely increase in the future, and climate change is likely to exacerbate these issues. The other cluster of respondents was bullish, or optimistic: they foresaw fewer future water conflicts and fewer socio-political barriers to implementation. Despite these differences, both clusters largely identified the same data needs and barriers to e-flows implementation. Our social network analysis revealed that the frequency of communication between clusters was not significantly different than the frequency of communication within clusters. Overall, our results suggest that the different perspectives of decision-makers could complicate efforts to implement e-flows and proactively plan for climate change. However, there are opportunities for collaboration on addressing common data needs and barriers to implementation. Overall, our study provides a key socio-environmental perspective on e-flows implementation from a semi-arid and socio-politically complex river basin and contextualizes the many challenges facing e-flows implementation in river basins globally.

Peak grain forecasts for the US High Plains amid withering waters

Rapid groundwater depletion represents a significant threat to food and water security because groundwater supplies more than 20% of global water use, especially for crop irrigation. A large swath of the US High Plains, which produces more than 50 million tons of grain yearly, depends on the Ogallala aquifer for more than 90% of its irrigation needs. A predator–prey-type model serves as a minimalist representation of groundwater use–crop production dynamics. It explains and predicts reductions in groundwater withdrawal on three High Plains states and subsequent declines in irrigated crop production. The model shows how recharge rates and the adoption of irrigation technologies control these trends. It also provides a general framework for assessing groundwater-based irrigation sustainability.

Irrigated agriculture contributes 40% of total global food production. In the US High Plains, which produces more than 50 million tons per year of grain, as much as 90% of irrigation originates from groundwater resources, including the Ogallala aquifer. In parts of the High Plains, groundwater resources are being depleted so rapidly that they are considered nonrenewable, compromising food security. When groundwater becomes scarce, groundwater withdrawals peak, causing a subsequent peak in crop production. Previous descriptions of finite natural resource depletion have utilized the Hubbert curve. By coupling the dynamics of groundwater pumping, recharge, and crop production, Hubbert-like curves emerge, responding to the linked variations in groundwater pumping and grain production. On a state level, this approach predicted when groundwater withdrawal and grain production peaked and the lag between them. The lags increased with the adoption of efficient irrigation practices and higher recharge rates. Results indicate that, in Texas, withdrawals peaked in 1966, followed by a peak in grain production 9 y later. After better irrigation technologies were adopted, the lag increased to 15 y from 1997 to 2012. In Kansas, where these technologies were employed concurrently with the rise of irrigated grain production, this lag was predicted to be 24 y starting in 1994. In Nebraska, grain production is projected to continue rising through 2050 because of high recharge rates. While Texas and Nebraska had equal irrigated output in 1975, by 2050, it is projected that Nebraska will have almost 10 times the groundwater-based production of Texas.

What Factors Drive the Changes in Water Withdrawals in the U.S. Agriculture and Food Manufacturing Industries between 1995 and 2010?

Climate change and increasing world population will directly impact the global food supply chain linkages. In the United States, agricultural production requires less irrigated water than before but it still accounts for a third of total water withdrawals. To better understand the evolution of its water use, we perform a structural decomposition analysis of water withdrawals across eight different crops and six livestock categories and differentiate the trends over 1995-2005 vs 2005-2010 to account for the role of the economic crisis in the second period. Based on USGS data, the results show that both periods experienced an overall decline in water withdrawals in the production of all crops except oilseeds. This trend is driven by a decrease in water intensity, reflecting greater efficiency of irrigation systems, and by reduced local per capita income in the second period. However, increased foreign demand for water-intensive sectors like oilseeds from NAFTA and Asian partners mitigated the decline. Results indicate also a decreasing water use in livestock production partially due to a shift from red to white meat consumption in the country. Arguably, recent tariff wars and border closures have greatly reduced the virtual water embodied in American exports.

Sustainability management of short-lived freshwater fish in human-altered ecosystems should focus on adult survival

Fish populations globally are susceptible to endangerment through exploitation and habitat loss. We present theoretical simulations to explore how reduced adult survival (age truncation) might affect short-lived freshwater fish species in human-altered contemporary environments. Our simulations evaluate two hypothetical "average fish" and five example fish species of age 1 or age 2 maturity. From a population equilibrium baseline representing a natural, unaltered environment we impose systematic reductions in adult survival and quantify how age truncation affects the causes of variation in population growth rate. We estimate the relative contributions to population growth rate arising from simulated temporal variation in age-specific vital rates and population structure. At equilibrium and irrespective of example species, population structure (first adult age class) and survival probability of the first two adult age classes are the most important determinants of population growth. As adult survival decreases, the first reproductive age class becomes increasingly important to variation in population growth. All simulated examples show the same general pattern of change with age truncation as known for exploited, longer-lived fish species in marine and freshwater environments. This implies age truncation is a general potential concern for fish biodiversity across life history strategies and ecosystems. Managers of short-lived, freshwater fishes in contemporary environments often focus on supporting reproduction to ensure population persistence. However, a strong focus on water management to support reproduction may reduce adult survival. Sustainability management needs a focus on mitigating adult mortality in human-altered ecosystems. A watershed spatial extent embracing land and water uses may be necessary to identify and mitigate causes of age truncation in freshwater species. Achieving higher adult survival will require paradigm transformations in society and government about water management priorities.

Urban water systems: Development of micro-level indicators to support integrated policy

Urban water systems involve complex interactions between ecological, social and economic factors. Integrated management approaches are needed to achieve multiple policy objectives in the sector and can be pursued at a range of spatial scales. Small-scale integrated water projects are both feasible and valuable in dynamic urban environments in developing countries. This paper develops a method for the prioritization of localities for integrated projects and applies this to the city of Jakarta. A set of indicators is defined following a systems approach, populated, displayed through a dashboard and mapped, and the relationships between indicators are analysed. Indicator-based prioritization allows policy-makers to guide resources to integrated projects to contribute effectively to the achievement of policy goals.

Urban drought challenge to 2030 sustainable development goals

In the first two decades of the 21st century, 79 global big cities have suffered extensively from drought disaster. Meanwhile, climate change has magnified urban drought in both frequency and severity, putting tremendous pressure on a city's water supply. Therefore, tackling the challenges of urban drought is an integral part of achieving the targets set in at least 5 different Sustainable Development Goals (SDGs). Yet, the current literatures on drought have not placed sufficient emphasis on urban drought challenge in achieving the United Nations' 2030 Agenda for Sustainable Development. This review is intended to fill this knowledge gap by identifying the key concepts behind urban drought, including the definition, occurrence, characteristics, formation, and impacts. Then, four sub-categories of urban drought are proposed, including precipitation-induced, runoff-induced, pollution-induced, and demand-induced urban droughts. These sub-categories can support city stakeholders in taking drought mitigation actions and advancing the following SDGs: SDG 6 "Clean water and sanitation", SDG 11 "Sustainable cities and communities", SDG 12 "Responsible production and consumption", SDG 13 "Climate actions", and SDG 15 "Life on land". To further support cities in taking concrete actions in reaching the listed SDGs, this perspective proposes five actions that city stakeholders can undertake in enhancing drought resilience and preparedness:1) Raising public awareness on water right and water saving; 2) Fostering flexible reliable, and integrated urban water supply; 3) Improving efficiency of urban water management; 4) Investing in sustainability science research for urban drought; and 5) Strengthening resilience efforts via international cooperation. In short, this review contains a wealth of insights on urban drought and highlights the intrinsic connections between drought resilience and the 2030 SDGs. It also proposes five action steps for policymakers and city stakeholders that would support them in taking the first step to combat and mitigate the impacts of urban droughts.

Analysing progress of sustainable development goal 6 in India: Past, present, and future

The attainment of sustainable development in water and sanitation i.e. Sustainable Development Goal 6 (SDG 6) requires a comprehensive monitoring and knowledge base of social and economic water needs at national scale in such a way that should not cause negative environmental manifestations from regional to global scale. India holds a key position among developing economies with a complex interconnected web of fast-growing population, coupled with biophysical stress, social deprivation and economic inequality related to utilization, availability and access to water resources and sanitation facilities. This study addresses some of these challenges related to monitoring and implementation of the targets of the UN SDG 6 in India. Acknowledging the contribution of society and economy in sustainability paradigm, here we have chosen 28 indicators (clustered into 11 dimensions) under two major groups, concerning biophysical and social development aspects of water and sanitation. We have shown declining level of per capita biophysical water resource and slow to rapidly developing societal indicators related to SDG 6 in India. From past trends, we have calculated probable scenario of biophysical consumption of India up to 2050. We have also analysed the interrelationship of water and sanitation (SDG 6) with health (SDG 3) and end to poverty (SDG 1) in India. These show a positive impact of increasing per capita GDP on improving sanitation related indicators, which in turn positively influence to reduce water and sanitation related diseases, especially in children and aged population. This cumulative assessment framework contributes a tool to prioritize water resource appropriation and assessment of sanitation, management response and policy implementations to national level inclusive sustainability of water and sanitation sector, keeping in mind the societal and economic development scenario in India.