Showing papers on "Water scarcity published in 2021"

Risk of pesticide pollution at the global scale

Abstract: Pesticides are widely used to protect food production and meet global food demand but are also ubiquitous environmental pollutants, causing adverse effects on water quality, biodiversity and human health Here we use a global database of pesticide applications and a spatially explicit environmental model to estimate the world geography of environmental pollution risk caused by 92 active ingredients in 168 countries We considered a region to be at risk of pollution if pesticide residues in the environment exceeded the no-effect concentrations, and to be at high risk if residues exceeded this by three orders of magnitude We find that 64% of global agricultural land (approximately 245 million km2) is at risk of pesticide pollution by more than one active ingredient, and 31% is at high risk Among the high-risk areas, about 34% are in high-biodiversity regions, 5% in water-scarce areas and 19% in low- and lower-middle-income nations We identify watersheds in South Africa, China, India, Australia and Argentina as high-concern regions because they have high pesticide pollution risk, bear high biodiversity and suffer from water scarcity Our study expands earlier pesticide risk assessments as it accounts for multiple active ingredients and integrates risks in different environmental compartments at a global scale Pesticide pollution is a risk for two-thirds of agriculture land A third of high-risk areas are in high-biodiversity regions and a fifth are in low- and lower-middle-income areas, according to environmental modelling combined with pesticide application data

Future global urban water scarcity and potential solutions.

Abstract: Urbanization and climate change are together exacerbating water scarcity-where water demand exceeds availability-for the world's cities. We quantify global urban water scarcity in 2016 and 2050 under four socioeconomic and climate change scenarios, and explored potential solutions. Here we show the global urban population facing water scarcity is projected to increase from 933 million (one third of global urban population) in 2016 to 1.693-2.373 billion people (one third to nearly half of global urban population) in 2050, with India projected to be most severely affected in terms of growth in water-scarce urban population (increase of 153-422 million people). The number of large cities exposed to water scarcity is projected to increase from 193 to 193-284, including 10-20 megacities. More than two thirds of water-scarce cities can relieve water scarcity by infrastructure investment, but the potentially significant environmental trade-offs associated with large-scale water scarcity solutions must be guarded against.

Observed increasing water constraint on vegetation growth over the last three decades.

Abstract: Despite the growing interest in predicting global and regional trends in vegetation productivity in response to a changing climate, changes in water constraint on vegetation productivity (i.e., water limitations on vegetation growth) remain poorly understood. Here we conduct a comprehensive evaluation of changes in water constraint on vegetation growth in the extratropical Northern Hemisphere between 1982 and 2015. We document a significant increase in vegetation water constraint over this period. Remarkably divergent trends were found with vegetation water deficit areas significantly expanding, and water surplus areas significantly shrinking. The increase in water constraints associated with water deficit was also consistent with a decreasing response time to water scarcity, suggesting a stronger susceptibility of vegetation to drought. We also observed shortened water surplus period for water surplus areas, suggesting a shortened exposure to water surplus associated with humid conditions. These observed changes were found to be attributable to trends in temperature, solar radiation, precipitation, and atmospheric CO2. Our findings highlight the need for a more explicit consideration of the influence of water constraints on regional and global vegetation under a warming climate.

Global water scarcity including surface water quality and expansions of clean water technologies

Abstract: Water scarcity threatens people in various regions, and has predominantly been studied from a water quantity perspective only. Here we show that global water scarcity is driven by both water quantity and water quality issues, and quantify expansions in clean water technologies (i.e. desalination and treated wastewater reuse) to ‘reduce the number of people suffering from water scarcity’ as urgently required by UN’s Sustainable Development Goal 6. Including water quality (i.e. water temperature, salinity, organic pollution and nutrients) contributes to an increase in percentage of world’s population currently suffering from severe water scarcity from an annual average of 30% (22%–35% monthly range; water quantity only) to 40% (31%–46%; both water quantity and quality). Water quality impacts are in particular high in severe water scarcity regions, such as in eastern China and India. In these regions, excessive sectoral water withdrawals do not only contribute to water scarcity from a water quantity perspective, but polluted return flows degrade water quality, exacerbating water scarcity. We show that expanding desalination (from 2.9 to 13.6 billion m3 month−1) and treated wastewater uses (from 1.6 to 4.0 billion m3 month−1) can strongly reduce water scarcity levels and the number of people affected, especially in Asia, although the side effects (e.g. brine, energy demand, economic costs) must be considered. The presented results have potential for follow-up integrated analyses accounting for technical and economic constraints of expanding desalination and treated wastewater reuse across the world.

Evaluating the economic impact of water scarcity in a changing world.

Abstract: Water scarcity is dynamic and complex, emerging from the combined influences of climate change, basin-level water resources, and managed systems' adaptive capacities. Beyond geophysical stressors and responses, it is critical to also consider how multi-sector, multi-scale economic teleconnections mitigate or exacerbate water shortages. Here, we contribute a global-to-basin-scale exploratory analysis of potential water scarcity impacts by linking a global human-Earth system model, a global hydrologic model, and a metric for the loss of economic surplus due to resource shortages. We find that, dependent on scenario assumptions, major hydrologic basins can experience strongly positive or strongly negative economic impacts due to global trade dynamics and market adaptations to regional scarcity. In many cases, market adaptation profoundly magnifies economic uncertainty relative to hydrologic uncertainty. Our analysis finds that impactful scenarios are often combinations of standard scenarios, showcasing that planners cannot presume drivers of uncertainty in complex adaptive systems.

Protein nanofibrils for next generation sustainable water purification.

Abstract: Water scarcity is rapidly spreading across the planet, threatening the population across the five continents and calling for global sustainable solutions Water reclamation is the most ecological approach for supplying clean drinking water However, current water purification technologies are seldom sustainable, due to high-energy consumption and negative environmental footprint Here, we review the cutting-edge technologies based on protein nanofibrils as water purification agents and we highlight the benefits of this green, efficient and affordable solution to alleviate the global water crisis We discuss the different protein nanofibrils agents available and analyze them in terms of performance, range of applicability and sustainability We underline the unique opportunity of designing protein nanofibrils for efficient water purification starting from food waste, as well as cattle, agricultural or dairy industry byproducts, allowing simultaneous environmental, economic and social benefits and we present a case analysis, including a detailed life cycle assessment, to establish their sustainable footprint against other common natural-based adsorbents, anticipating a bright future for this water purification approach

Engineered two-dimensional nanomaterials: an emerging paradigm for water purification and monitoring

Abstract: Water scarcity has become an increasingly complex challenge with the growth of the global population, economic expansion, and climate change, highlighting the demand for advanced water treatment technologies that can provide clean water in a scalable, reliable, affordable, and sustainable manner. Recent advancements on 2D nanomaterials (2DM) open a new pathway for addressing the grand challenge of water treatment owing to their unique structures and superior properties. Emerging 2D nanostructures such as graphene, MoS2, MXene, h-BN, g-C3N4, and black phosphorus have demonstrated an unprecedented surface-to-volume ratio, which promises ultralow material use, ultrafast processing time, and ultrahigh treatment efficiency for water cleaning/monitoring. In this review, we provide a state-of-the-art account on engineered 2D nanomaterials and their applications in emerging water technologies, involving separation, adsorption, photocatalysis, and pollutant detection. The fundamental design strategies of 2DM are discussed with emphasis on their physicochemical properties, underlying mechanism and targeted applications in different scenarios. This review concludes with a perspective on the pressing challenges and emerging opportunities in 2DM-enabled wastewater treatment and water-quality monitoring. This review can help to elaborate the structure–processing–property relationship of 2DM, and aims to guide the design of next-generation 2DM systems for the development of selective, multifunctional, programmable, and even intelligent water technologies. The global significance of clean water for future generations sheds new light and much inspiration in this rising field to enhance the efficiency and affordability of water treatment and secure a global water supply in a growing portion of the world.

Water Security in a Changing Environment: Concept, Challenges and Solutions

Abstract: Water is of vital and critical importance to ecosystems and human societies. The effects of human activities on land and water are now large and extensive. These reflect physical changes to the environment. Global change such as urbanization, population growth, socioeconomic change, evolving energy needs, and climate change have put unprecedented pressure on water resources systems. It is argued that achieving water security throughout the world is the key to sustainable development. Studies on holistic view with persistently changing dimensions is in its infancy. This study focuses on narrative review work for giving a comprehensive insight on the concept of water security, its evolution with recent environmental changes (e.g., urbanization, socioeconomic, etc.) and various implications. Finally, it presents different sustainable solutions to achieve water security. Broadly, water security evolves from ensuring reliable access of enough safe water for every person (at an affordable price where market mechanisms are involved) to lead a healthy and productive life, including that of future generations. The constraints on water availability and water quality threaten secured access to water resources for different uses. Despite recent progress in developing new strategies, practices and technologies for water resource management, their dissemination and implementation has been limited. A comprehensive sustainable approach to address water security challenges requires connecting social, economic, and environmental systems at multiple scales. This paper captures the persistently changing dimensions and new paradigms of water security providing a holistic view including a wide range of sustainable solutions to address the water challenges.

The widespread and unjust drinking water and clean water crisis in the United States.

Abstract: Many households in the United States face issues of incomplete plumbing and poor water quality. Prior scholarship on this issue has focused on one dimension of water hardship at a time, leaving the full picture incomplete. Here we complete this picture by documenting the full scope of water hardship in the United States and find evidence of a regionally-clustered, socially unequal nationwide household water crisis. Using data from the American Community Survey and the Environmental Protection Agency, we show there are 489,836 households lacking complete plumbing, 1,165 community water systems in Safe Drinking Water Act Serious Violation, and 21,035 Clean Water Act permittees in Significant Noncompliance. Further, we demonstrate this crisis is regionally clustered, with the specific spatial pattern varying by the specific form of water hardship. Elevated levels of water hardship are associated with the social dimensions of rurality, poverty, indigeneity, education, and age—representing a nationwide environmental injustice. Proper water and sanitation access remains an issue for many in the United States. Here the authors estimate and map the full scope of water hardship, including both incomplete plumbing and water quality across the country.

Interfacial Solar Vapor Generation: Materials and Structural Design

Abstract: ConspectusThe global water scarcity and deteriorating environment call for the development of environmentally friendly water treatment technologies. Solar-driven evaporation, well-known as a critic...

Atmospheric dynamic constraints on Tibetan Plateau freshwater under Paris climate targets

Abstract: Rivers originating in the Tibetan Plateau provide freshwater to downstream populations, yet runoff projections from warming are unclear due to precipitation uncertainties. Here, we use a historical atmospheric circulation–precipitation relationship to constrain future modelled wet-season precipitation over the Tibetan Plateau. Our constraint reduces precipitation increases to half of those from the unconstrained ensemble and reduces spread by around a factor of three. This constrained precipitation is used with estimated glacier melt contributions to constrain future runoff for seven rivers. We estimate runoff increases of 1.0–7.2% at the end of the twenty-first century for global mean warming of 1.5–4 °C above pre-industrial levels. Because population projections diverge across basins, this runoff increase will reduce the population fraction living under water scarcity conditions in the Yangtze and Yellow basins but not in the Indus and Ganges basins, necessitating improved water security through climate change adaptation policies in these regions at higher risk. Tibetan Plateau runoff projections are uncertain due to precipitation change uncertainty in climate models. Historical precipitation–circulation relationships constrain future wet-season precipitation and runoff change, suggesting worsening water scarcity for the Indus and Ganges river basins.

Wastewater reclamation and reuse potentials in agriculture: towards environmental sustainability

Abstract: Water scarcity is the major concern that impacts the global economy and the livelihood of mankind. Climate change, rapid population growth, freshwater pollution, and depletion are among the factors that aggravate the situation. Although not yet exhaustively exploited, reclamation and reuse of wastewater are considered as potential mechanisms to mitigate the challenge. In relation to reclamation, conventional wastewater treatment plants are designed to remove organic matter, total solids, and nutrients but fail to remove the emerging micropollutants. A decentralized wastewater treatment system is another potential and emerging approach for sustainable water reuse at the point of the wastewater generation. However, its application is not exclusively independent of the centralized system; rather the integration of the two systems is recommendable to depend on the local situations. To remove micropollutants, integrating advanced wastewater technologies should be considered as well as advanced analytical instruments for proper monitoring. Although the reuse of reclaimed water in crop irrigation is a well-established practice, it lacks uniformity across the globe. Furthermore, if not properly monitored, the reuse of reclaimed water also has adverse effects on the soil properties and public health. Therefore, the aim of this work is to review the impacts of global freshwater scarcity, water resources management and monitoring practice, state-of-the-art (waste)water treatment technologies and experience of reusing reclaimed water, particularly in agricultural irrigation.

Groundwater availability and water demand sustainability over the upper mega aquifers of Arabian Peninsula and west region of Iraq

Abstract: The current research is devoted to highlight the past, present and future status of groundwater characteristics over the Arabian Peninsula (AP) and west region of Iraq. The Umm er Radhuma, Rus Dammam and Neogene deposits are the major hydrostratigraphic units supplying the main groundwater resources in the AP. Water shortage is still a major problem for many countries in the world, including oil-producing countries such as Iraq, Saudi Arabia (SA), the United Arab Emirates (UAE), Qatar, Oman and Bahrain. The withdrawal of groundwater has been reflected in salinization of agricultural soils, leading to an increase in high-cost technologies such as desalination of seawater to provide suitable water for diverse sectors. Hence, the use of seawater desalination as a major source of water is unavoidable, and country development requires the use of renewable energy as protection of the environment. The need to conserve and use groundwater resources efficiently is highly essential owing to the fact that it is the only natural source of water in such developing countries of global importance. The review comprises various essential components related to groundwater variability including the hydrogeological aspects, climate change, drawdown and abstraction, rainwater harvesting, desertification and population increment. Based on the reviewed perspectives, various practical visions are discussed for better groundwater management and sustainability. This research is presented as a milestone for diverse future works and investigation that might be conducted for better water resources management over the AP region.

The water footprint of carbon capture and storage technologies

Abstract: Carbon capture and sequestration (CCS) is an important technology to reduce fossil CO2 emissions and remove CO2 from the atmosphere. Scenarios for CCS deployment consistent with global climate goals involve gigatonne-scale deployment of CCS within the next several decades. CCS technologies typically involve large water consumption during their energy-intensive capture process. Despite potential concerns, the water footprint of large-scale CCS adoption consistent with stringent climate change mitigation has not yet been explored. This study presents the water footprints (m3 water per tonne CO2 captured) of four prominent CCS technologies: Post-combustion CCS, Pre-combustion CCS, Direct Air CCS, and Bioenergy with CCS. Depending on technology, the water footprint of CCS ranges from 0.74 to 575 m3 H2O/tonne CO2. Bioenergy with CCS is the technology that has the highest water footprint per tonne CO2 captured, largely due to the high water requirements associated with transpiration. The widespread deployment of CCS to meet the 1.5 °C climate target would almost double anthropogenic water footprint. Consequently, this would likely exacerbate and create green and blue water scarcity conditions in many regions worldwide. Climate mitigation scenarios with a diversified portfolio of CCS technologies have lower impacts on water resources than scenarios relying mainly on one of them. The water footprint assessment of CCS is a crucial factor in evaluating these technologies. Water-scarce regions should prioritize water-efficient CCS technologies in their mitigation goals. In conclusion, the most water-efficient way to stabilize the Earth's climate is to rapidly decarbonize our energy systems and improve energy efficiency.

Transboundary cooperation a potential route to sustainable development in the Indus basin

Abstract: With a rapidly growing population of 250 million, the Indus river basin in South Asia is one of the most intensively cultivated regions on Earth, highly water stressed and lacking energy security. Yet, most studies advising sustainable development policy have lacked multi-sectoral and cross-country perspectives. Here we show how the countries in the Indus basin could lower costs for development and reduce soil pollution and water stress by cooperating on water resources and electricity and food production. According to this analysis, Indus basin countries need to increase investments to US$10 billion per yr to mitigate water scarcity issues and ensure improved access to resources by 2050. These costs could shrink to US$2 billion per yr, with economic gains for all, if countries pursued more collaborative policies. Downstream regions would benefit most, with reduced food and energy costs and improved water access, while upstream regions would benefit from new energy investments. Using integrated water–energy–land analysis, this study quantifies the potential benefits of novel avenues to sustainable development arising from greater international cooperation. The Indus river basin in South Asia is water stressed, energy insecure and intensively farmed, and research on this region often lacks a systemic approach to the issues. This study shows how the path to development in the region could be made less costly and more environmentally friendly by fostering transboundary cooperation.

Unprecedented drought in South India and recent water scarcity

Abstract: Peninsular Indian agriculture and drinking water availability are critically reliant on seasonal winter rainfall occurring from October to December, associated with the northeastern monsoon (NEM). Over 2016–2018, moderate-to-exceptionally low NEM rainfall gave rise to severe drought conditions over much of southern India and exacerbated water scarcity. The magnitude and dynamics of this drought remain unexplored. Here, we quantify the severity of this event and explore causal mechanisms of drought conditions over South India. Our findings indicate that the 3-year cumulative rainfall totals of NEM rainfall during this event faced a deficit of more than 40%—the driest 3-year period in ∼150 years according to the observational record. We demonstrate that drought conditions linked to the NEM across South India are associated with cool phases in the equatorial Indian and Pacific Oceans. Future changes in these teleconnections will add to the challenges of drought prediction.

Day Zero and The Infrastructures of Climate Change: Water Governance, Inequality, and Infrastructural Politics in Cape Town's Water Crisis

Abstract: From 2015 to 2018, Cape Town, South Africa, was marked by fears of a water crisis in which the city's taps threatened to run dry. We argue in this article that Cape Town's crisis of water scarcity was a product of the convergence of ongoing contradictions in South African water governance as they came into contact with shifting infrastructural priorities associated with climate change. In its response to the possibility of a financial crisis brought on by reduced water consumption, the city withdrew the universal provision of free basic water (FBW) and reconfigured existing tariff structures. Both changes meant that the city moved further into commercialization and valuation practices in the context of restricted monetary flows. Based on an understanding of contemporary governance in South Africa as reflective of an often contradictory need to balance municipal budgets while also correcting for apartheid inequities, we argue that ongoing experiences of climate change are stretching existing municipal budgets in ways that threaten to deepen existing inequalities. Ultimately, we suggest that Cape Town's crisis is critical for understanding how climate change is reconfiguring existing governance dynamics at a planetary scale, thus offering insights into what form urban climate change adaptation may take in the future.

A Review of Water Stress and Water Footprint Accounting

Abstract: Production and consumption activities deplete freshwater, generate water pollution and may further lead to water stress. The accurate measurement of water stress is a precondition for sustainable water management. This paper reviews the literature on physical water stress induced by blue and green water use and by water pollution. Specifically, we clarify several key concepts (i.e., water stress, scarcity, availability, withdrawal, consumption and the water footprint) for water stress evaluation, and review physical water stress indicators in terms of quantity and quality. Furthermore, we identify research gaps in physical water stress assessment, related to environmental flow requirements, return flows, outsourcing of water pollution and standardization of terminology and approaches. These research gaps can serve as venues for further research dealing with the evaluation and reduction of water stress.