Riverine exports of total nitrogen (TN) and total phosphorus (TP) are major drivers of coastal eutrophication. However, few studies have quantified the reductions required to mitigate future eutrophication risks under changing socio-economic and climatic conditions. Here, we use three global water quality models (Integrated Model to Assess the Global Environment-Dynamic Global Nutrient Model, CoSWAT-WQ, and MARINA-Multi) to project TN and TP export loads from twenty four of the world’s largest river basins under a high-emission and high socio-economic growth scenario (SSP5-Representative Concentration Pathways 8.5). Our multi-model mean projections indicate that TN and TP exports from these basins could increase by 18% and 21%, respectively, by 2050 relative to 2010 export levels. To avoid the risk of future coastal eutrophication, we estimate reductions in TN and TP riverine exports to coastal waters of approximately 67% and 64%, respectively by 2050. In particular, major river basins such as the Nile, Niger, Yangtze, Ganges, Danube, São Francisco, and Zhujiang will require nutrient load reductions exceeding 50% for both TN and TP. Ultimately, achieving the necessary nutrient reductions will require coordinated, targeted interventions to protect our global coastal ecosystems. Meanwhile, the variability among model simulations underscores the need to advance global water quality modeling frameworks to reduce uncertainties and better support science-based policy making.

Many global regions, including East Africa, implement policy goals advocating increased agricultural self-sufficiency to promote economic development and food security. Required increases in production can, however, negatively impact the environment. We assessed upscaling sustainable rice intensification in East Africa, comparing regional trade and environmental policy scenarios using a novel hydro-economic modeling framework that optimizes farmer profit subject to technical and resource constraints. Allocating rice production to current croplands, where rainfed rice production is economically competitive with other crops, can achieve regional rice self-sufficiency in 2050 with limited environmental impacts. Regionally integrated trade further increases rice production (+14%), improves resilience to climate shocks (-46% production losses), and reduces water use (-81%) and greenhouse gas emissions (-7%). Negative impacts of climate shocks could be avoided by expanding irrigated rice production. To realize these benefits, East African countries need moderate productivity upgrading, investment in infrastructure, especially for irrigation, and enhanced regional cooperation, including trade agreements and benefit-sharing mechanisms, as well as joint planning and access to production inputs, land and water resources.

Water is withdrawn, lost, consumed, polluted, returned, treated, reused, and traded between regions within the societal water cycle due to human activities, contributing to regional water stress. In this research, we aim to examine the impacts of the societal water cycle on water resources and explore strategies for reducing water stress in China. The results show that most provinces in China suffer from water quantity and quality stress. However, there is a significant potential to reduce water quantity stress by 36-79 % through reducing water loss and return flows. The return flows and water loss in the virtual export forms could be avoided to reduce virtual water export-induced quantity stress by 39-89 %. Agriculture and households' return flows contribute 61-98 % to provincial water quality stress in China. The five sectors with the greatest potential to mitigate water quantity and quality stress are identified for each province, which could reduce quantity stress by 22-75 % and quality stress by 23-76 %.

Abstract Developing regions face critical water security challenges driven by rapid urban growth, economic development, and climate change. In India, these issues are particularly evident in Pune, the country's 9th most populated city. It is evolving into a sprawling urban agglomeration expected to grow from 7 to 11 million residents by mid‐century. The city's aging water‐supply system is ill‐equipped to ensure water access during droughts lasting 2–3 years, particularly for residents in informal settlements. We present a policy‐evaluation model to assess options for addressing future urban freshwater insecurity. The model uses a coupled multi‐agent systems approach that integrates human‐environment interactions and responses to future drought, population, and economic conditions. Under business‐as‐usual for a mid‐century, multi‐year drought, major reservoirs dry up and groundwater levels decrease dramatically. The water use Gini coefficient exceeds 0.5, indicating severe inequality where most low‐income individuals face: (a) unaffordable water costs (10%–18% of income), (b) vulnerability (<40 L daily), and (c) prolonged shortages (>6 continuous months). Comprehensive interventions, combining supply‐ and demand‐side measures, cut the water use Gini coefficient in half and lower water costs by two‐thirds. Implementing a strategic subset of interventions creates synergies that significantly enhance water security, yet remains insufficient for the low‐income population. This study highlights how growing inequalities in urban water access exacerbate water security challenges, even under a suite of mitigating measures. In all scenarios, additional drought emergency supply will be required to address water insecurity of the lowest 10% income population.

Study region This research focuses on the Guadalquivir River Basin in southern Spain, a region characterized by high agricultural water demand and increasing vulnerability to drought. The basin serves as a critical case study for semi-arid Mediterranean environments. Study focus The study evaluates the impact of three distinct water allocation rules: proportional allocation (uniform allotment reductions), proportional economic losses (equalized relative reduction in gross margins), and optimal allocation (prioritization of water-productive crops). Using a hydro-economic model, the research simulates various scarcity scenarios (10% to 70% reductions) and examines the mitigating role of groundwater reserves during periods of drought. New hydrological insights for the region The findings reveal that while proportional allocation is often perceived as equitable, it results in the most severe and uneven economic losses (16.1% at a 50% water deficit). In contrast, an optimal allocation rule minimizes aggregate losses to 12.0%. Access to groundwater significantly cushions the impact, reducing losses to approximately 5.3%–7.0%. The study highlights that traditional water-sharing rules are economically inefficient and socially inequitable, advocating for a transition toward allocation models based on economic efficiency and territorial equity to ensure water sustainability in an uncertain climate. Overall, our results provide a policy-relevant quantification of the efficiency–equity trade-offs of drought rationing and show that strategic conjunctive use can substantially increase irrigation resilience in semi-arid, agriculture-dominated basins.

Drought hazards have intensified in many world regions during the recent century, exposing multiple environmental and socio-economic systems to increased risks. Nevertheless, estimating drought risk is still challenging due to the complex links between drought hazards and their potentially disastrous impacts. The recently published JRC European drought risk atlas, an outcome of the European Drought Observatory for Resilience and Adaptation (EDORA) project, has utilized a data-driven approach, linking drought’s hazard, vulnerability, and exposure with observed sectoral impacts. This project links theoretical causal impact chains and quantitative outcome-oriented drought risk assessment, resulting in a high-resolution assessment of drought-driven sectoral impacts, which can support drought management, and adaptation policies and actions. At the European level, long time series of observed impacts may be limited in terms of spatial or sectoral coverage, relevance, or granularity. However, specific countries often collect and compile sub-national resolution impact data relevant to drought risk assessment that can inform management and adaptation policies and actions. Implementation at a subnational scale using customized country specific data can be a valuable tool to assess drought risk and impact. However, ensuring valid and reliable results would require following a standard procedure. We explore this potential and delve one step deeper by conducting a national data-driven drought risk assessment in Romania. We use data from various Romanian government agencies to examine drought-associated impacts on water supply, hydroelectricity energy production, and cultivated crop production. These spatially explicit national data provide larger coverage (cultivated crops), higher spatial resolution (hydroelectricity generation), and country-relevant data (drinking water supply to households) as compared to using Eurostat data for a Europe-wide approach. Data is not restricted only to these sectors; instead, it allows extending the sectoral coverage beyond that of the European drought risk atlas and exploring drought impacts on livestock productivity, water-dependent tourism, and forestry productivity, which are sectors of specific interest to the country. A preliminary assessment suggests a range of sectoral impacts associated with droughts in Romania. The livestock productivity suffers an average annual loss (AAL) of 1 -2%, the forestry sector presents 3% of AAL, and the tourism sector has the highest AAL, at around 6%. This proposed talk will focus on the potential of applying the Pan-European data-driven drought risk assessment method with nationally derived and diverse datasets, highlighting its flexibility in incorporating additional sectors. Specifically, we will present results for sectors not accounted for before. Finally, we will provide insights into the opportunities and limitations of standardizing the data-driven approach to conduct country-specific, sub-national drought risk assessments.

Climate change will exacerbate drought events in arid and semiarid basins, with longer and more intense drought spells. This will further jeopardize the sustainability of water systems in these basins, augmenting the uncertainty of streamflows and the risks of large economic and environmental damages. Hydro-economic modeling has been used already in the literature for analyzing the impacts of reduced water availability from climate change. However, previous studies do not consider the change in the scale of drought duration and intensity. This study closes this gap by combining hydro-economic analysis with a procedure based on copulas, where the copula procedure generates future climate water stress conditions with longer and more intense droughts. In this work, the joint probability function of two consecutive monthly water inflows is fitted by a Clayton copula, an asymmetric copula that captures the lower tail dependence implicit in drought persistence. Then, the hydro-economic model is used to analyze the economic impacts of climate change in the Ebro Basin of Spain. The reliability, resilience, and vulnerability of the water system are evaluated in order to assess the sustainability of the Ebro basin. Results show that there are costs of maladaptation when changes in drought duration and intensity from climate change are ignored, where maladaptation costs ensue from erroneous drought planning. Measures for drought management would be flawed because of the inaccurate evaluation of climate change hazards, given that the temporal dependence of climate variables is overlooked.

Sustainable management of aquifers in arid and semi-arid regions is crucial to ensure socio-environmental sustainability. Groundwater extraction regulation can be implemented through various instruments. Hydro-economic modeling methods offer significant insights which help to evaluate these instruments for effective groundwater regulation. Nonetheless, regulators can leverage the information generated by hydro-economic models to enhance their decision-making processes related to water allocation. This study evaluates the impact of water management instruments such as quotas, environmental taxes, and the quota-tax system on the sustainability of the Mahdia-Ksour Essef aquifer and the local economy, while also considering future climate projections, using hydro-economic modeling. By exploring various water management scenarios, the study offers strategic insights for enhancing resource allocation. The policies of quotas, adjusted according to natural recharge, as well as taxes and combined policies (quota-tax system) are examined and compared to the Business As Usual (BAU) scenario. The results show that policies based on quotas (only quotas and quota-taxes) allow for a faster replenishment of the aquifer and generate total revenues after taxes that are higher than those before taxes. For example, under the most pessimistic climate change scenario, a preservation quota for future generations could increase the actual aquifer level by 1.69 meters at the end of the simulation period. These policies could influence agricultural revenue by promoting more profitable and drought-resistant crops, such as olives and almonds. This study highlights the effectiveness of hydro-economic models as optimal approaches for evaluating groundwater management. Thus, it contributes to guiding policymakers toward strategic choices that promote sustainability and efficiency, particularly in the complex context of climate change and groundwater resource overexploitation.

Water resources face increasing pressure globally and regionally driven by rising water, energy and food demand, resulting in extensive resource abstraction and severe environmental consequences, including diminished water quantity and quality, groundwater depletion, and ecosystem degradation. The escalating impacts of climate change further compound these challenges by altering water availability and intensifying extreme events like droughts and floods. Addressing these issues necessitates the urgent establishment of a Safe Operating Space (SOS) for water systems, ensuring reliable and clean water supply for human activities and ecosystems in a changing climate and society. While various analytical frameworks have emerged to assess components of the water resources SOS, predominantly at a global scale (e.g., water planetary boundaries), their adoption in local and regional water management remains limited. Existing frameworks often lack comprehensive acknowledgement of relevant local and regional dimensions, including hydrological, infrastructure, ecological, and human processes. Moreover, spatial and temporal granularity tends to be insufficient for providing locally and regionally relevant information and for effectively engaging and supporting stakeholders. This is particularly evident in regions with high exposure to water scarcity where the complexity of infrastructure development and resource management is high. To bridge this gap, there is a crucial need to define the SOS framework at decision-relevant spatial scales, involving integrated efforts in data collection and modelling while also fostering a continuous dialogue with stakeholders to facilitate local and regional knowledge exchange. Our goal is to define and understand the SOS for water systems at local and regional scales to support the co-design of actionable management pathways. We propose a multi-dimensional SOS evaluation framework for local and regional water resources systems (SOS-Water) with four key components: 1) co-development of future scenarios and pathways, 2) integration of water system models (e.g., global hydrological models) and local and regional impact models, 3) identification of water system indicators for impact assessment with associated failure thresholds, and 4) determination of the multi-dimensional SOS for water systems. The SOS for the local and regional water systems is initially computed under baseline conditions, representing the status quo, and subsequently evaluated under diverse climate and socio-economic scenarios and management pathways. The multi-dimensional SOS, derived from the integrated modelling system, depicts performance for each indicator under varying conditions and is reinforced with different hierarchized objectives defined by the stakeholders through an inclusive and iterative participatory approach. Here, we will present the conceptual structure of the SOS-Water framework and some preliminary results of its evaluation for the Jucar River Basin (Spain), which is subject to significant water scarcity due to ongoing climate-induced impacts.

Global change encompasses on the environmental side components such as climate change, land degradation and pollution; and in the societal domain socioeconomic changes such as demography, economic development, and equality. This nexus is primarily driven by human activities and affects outcomes relevant for peoples’ well-being and viability through a network of interactions and feedbacks. Due to its strong influence on land surface and land-atmosphere processes and as a basis for food security and income, agriculture and rural livelihoods are at the heart of global change. Despite the close entanglement of rural populations, livelihoods, and agricultural production, their integrated assessment is so far hardly considered in large-scale and global foresight studies. Instead, most large-scale research on consequences of global change and potential solutions is still monothematic or combines few of the above elements. Integration across disciplines is taking place only to a limited extent, typically with static combinations of model outcomes. E.g., integrated land use models typically combine yield projections for changing climate with a priori projections of economic and population change. Other examples are the combination of independent projections of crop productivity and water availability to analyze adaptation potentials within the biophysical domain or across scientific domains the estimation of migration driven by changes in crop productivity and water availability. Importantly, both mono- and interdisciplinary studies are most often confined to business-as-usual scenarios or trajectories along shared socioeconomic pathways. Consequently, they do not capture feedbacks involving the human dimension and potentials for adaptation, and therefore lack outcomes that can inform on options for local and regional decision-making covering the water-food-population nexus. The state-of-the-art highlights a concerning lack of integrated approaches to model global change impacts and feedbacks across environmental and socioeconomic domains. Based on own research and literature that characterizes interactions in the water-food-population nexus under global change pressures and existing model types and approaches, we propose herein a platform for the quantitative integrated modelling and assessment of global change impacts and adaptation covering food and water security, land use, demography, migration, and adaptive capacity. Applications of such a modelling platform may address a wide range of pressing questions including shocks, their cascading effects and ultimate feedbacks (e.g. food security through output and input trade during and after Ukraine war; other historic shocks such as financial crisis; etc.); slow-onset global change impacts and adaptation; or transversal achievement of SDGs; and eventually serve as a first step towards the modelling of societal catastrophic change scenarios.

Water scarcity is one of the most critical global environmental challenges. Addressing this challenge requires implementing economically-profitable and environmentally-sustainable water management interventions across scales globally. This study presents the development of the global version of the ECHO hydro-economic model (ECHO-Global version 1.0), for assessing the economic and environmental performance of water management options. This global version covers 282 subbasins worldwide, includes a detailed representation of irrigated agriculture and its management, and incorporates economic benefit functions of water use in the agricultural, domestic and industrial sectors calibrated using the Positive Mathematical Programming (PMP) procedure alongside with the water supply cost. We used ECHO-Global to simulate the impact of alternative water management scenarios under future climate and socio-economic changes, with the aim of demonstrating its value for informing water management decision making. Results of these simulations are overall consistent with previous studies evaluating the global cost of water supply and adaptation to global changes. Moreover, these results show the changes in water use and water supply and their economic impacts in a spatially-explicit way across the world, and highlight the opportunities for reducing those impacts through improved water management. Overall, this study demonstrates the capacity of ECHO-Global to address emerging research and practical questions related to future economic and environmental impacts of global changes on water resources and to translate global water goals (e.g., SDG6) into national and local policies.

Wastewater treatment plays a crucial role in removing pollutants. Water conservation and reuse of wastewater help to reduce freshwater use and to alleviate water stress. However, the extent to which water conservation, wastewater treatment, and reuse can contribute to water stress mitigation is not clear. This study aims to investigate the impact of water conservation, wastewater treatment, and reuse on both water quantity and quality stress mitigation in China. The investigation is based on a dataset mapping water quantity and pollutant flows across 32 sectors in 31 provinces in 2017 and a dataset of 7411 wastewater treatment plants containing information on wastewater quantity and quality. The findings show that wastewater reuse can reduce provincial water quantity stress by less than 10% and alleviate water stress in 4 out of 25 water-stressed provinces. In contrast, water conservation can contribute to water quantity stress reduction by 31% on average. When water conservation measures and reuse are jointly implemented, quantity stress levels can significantly be alleviated in 19 out of 25 water-stressed provinces, with quantity stress reductions ranging from 25% to 74%. The contribution of wastewater treatment to water quality stress mitigation varies between 6% and 86%, with an average of 29%. Nevertheless, wastewater treatment cannot sufficiently safeguard most regions against water quality stress. This is evident as 25 out of 29 water quality-stressed provinces continue to suffer from quality stress despite implementing wastewater treatment and water conservation practices. Additional measures such as non-point-source pollution control should be implemented alongside wastewater treatment to eliminate provincial quality stress.

Pressures on water resources are fueling conflicts between sectors. This trend will likely worsen under future climate-induced water stress, jeopardizing food, energy and human water security in most arid and semi-arid regions. Probabilistic analysis using stochastic optimization modeling can characterize multi-sector vulnerabilities and risks associated with future water stress. This study identifies the probabilistic trade-offs between agricultural, urban and energy sectors in the Ebro Basin (Spain). Two intervention policies have been examined and compared: (i) agricultural priority, and (ii) energy priority, for two planning horizons 2040-2070 and 2070-2100. Results show that the human water security goal is achieved under both intervention policies. However, the achievement of the food and energy security goals depends on the policy objectives and on the spatial location of irrigation schemes and hydropower plants, which result in different stream flows across the basin. The policy choice results in substantially different benefit gains and losses by sector and therefore by location. Neither priority policy provides an equitable sharing of benefits among all sectors and locations under climate change, which is an important issue, because the success or failure of policy interventions would depend on the distribution of the gains and losses of benefits across the basin. Policy uptake by stakeholders would depend on reaching win-win outcomes where losers are compensated, while delivering acceptable levels of food, energy and human water security in large river basins. Information on the probabilistic trade-offs contributes to the design of water management strategies capable of addressing the multi-sector vulnerability.

The stress on water resources is very high in the Mediterranean region, with pressures driven by substantial irrigation withdrawals. The impacts of climate change will be severe in the region, which will require a more sustainable water management. In Spain, the strong growth in income and population has doubled water withdrawals and degraded water quality since the 1960s. Although water management in Spain is based on stakeholders' cooperation, the ample range of policy and investment initiatives has been unable to stop water scarcity in basins. The worst scarcity situation pervades the basins of southern Spain, which are almost closed basins with dwindling outflows in the Segura, Jucar and Guadalquivir estuaries. The Spanish plan for adaptation requires integrating climate change in water planning, and the adaptation measures considered are augmenting supply, curbing demand, irrigation modernization and better control of groundwater. Desalinated seawater and treated urban wastewater are already used in southern basins, and will be expanded in the short term. However, the water unbalance in the long term will require an enormous desalination capacity, or else a strong reduction of irrigation withdrawals, both with high costs to farmers. The evaluation of climate adaptation measures in selected basins indicates the outcomes from alternative policy strategies that impact economic activities and environmental flows.

The Danube River Basin, spanning 19 countries and covering 801,000 km², is the most international river basin in the world. This region faces diverse challenges related to water quantity, quality, groundwater management, and biodiversity, all of which are expected to intensify due to climate change. To address these challenges, a holistic and sustainable water management approach is needed—one that integrates environmental, social, and economic dimensions, ensures stakeholder involvement, and aligns with regulatory frameworks.Building on the Planetary Boundaries framework, the concept of Safe Operating Space (SOS) has emerged in the last decades to assess sustainable resource use within the Earth’s carrying capacity while maintaining human well-being. Within the Horizon Europe SOS-Water project, we are working to define the SOS for water resources in four case study sites across Europe and beyond (Danube, Rhine, Jucar and Mekong basins) using integrated modeling, monitoring, advanced indicators, and an inclusive and iterative participatory approach that actively engages stakeholders to co-define visions, water values, and management options.The resulting co-created SOS framework will inform the design of sustainable water management pathways that address current and future challenges. It aims to maximize the socio-economic and ecological value of water while promoting resilience and sustainability across the different river basins.This proposed talk will showcase the application of the SOS framework to the Danube Basin, highlighting its capability to integrate all the different aspects of the water dimension with stakeholder engagement and co-development of management pathways. We will present the preliminary framework co-developed with stakeholders for the Danube Basin and provide insights into the how it can be used to inform sustainable water management practices and address the critical water challenges facing the Danube Basin and other transboundary regions worldwide.

Wastewater treatment and reuse are becoming increasingly critical for enhancing water use efficiency and ensuring reliable water availability. Wastewater also significantly influences hydrological dynamics within urban watersheds. Although hydrological modeling has advanced to incorporate human-water interactions, large-scale and multi-resolution models often lack the comprehensive integration of wastewater treatment and reuse processes. This paper presents the new wastewater treatment and reuse module as part of the hydrological Community Water Model (CWatM) and demonstrates its capabilities and advantages in an urban watershed with intermittent flows. Incorporating wastewater into the model improves model performance by better representing low and peak flows during the respective dry and wet seasons. It allows for the representation of sectoral wastewater reuse, the exploration of different measures to increase wastewater reuse, and the examination of the effects of wastewater reuse on the water stress level. Modeling wastewater treatment and reuse is particularly relevant in regions with semi-arid or arid climates, rapid urbanization, or active policies promoting water reuse. The wastewater treatment and reuse module could be upscaled by minimizing the data requirements via simplified workflows. Combined with the availability of recent datasets on wastewater treatment plants and processes, a global application of the module is feasible. As current developments focus on water quantity, the water quality dimension of wastewater treatment remains a limitation. This opens prospects for incorporating water quality into the model and developing global input data for wastewater treatment and reuse.

Improving nitrogen use efficiency (NUE) is crucial for sustainable agriculture. Despite recent advancements, China continues to face significant environmental risks due to nitrogen surplus. This study examines the spatiotemporal dynamics of cropland nitrogen use across 350 prefecture-level cities from 1980 to 2020. Results reveal a persistent “three highs and one low” pattern-high input, high output, high surplus, and low NUE. Although NUE increased from 35 % in 2003 to 49 % in 2020, the turning point occurred around 2005, coinciding with the national fertilizer reduction policy. Significant regional disparities remain, with low NUE in the Northwest and Qinghai-Tibet Plateau and high NUE in the Northeast and Sichuan Basin. A temporal lag between nitrogen input and NUE highlights the legacy effects of past nitrogen accumulation. Practices such as straw return and manure recycling in key regions have demonstrated benefits. Findings underscore the need for region-specific, resource-efficient nitrogen governance strategies to enhance long-term sustainability.

La gestion durable des aquifères dans les régions arides et semi-arides est cruciale pour assurer la durabilité socio-environnementale. La régulation des prélèvements d’eau souterraine peut être réalisée à travers plusieurs instruments. La modélisation hydro-économique fournit des perspectives pour l’analyse de l’efficacité de ces instruments en vue d’une gestion efficace des ressources en eau. En effet, ces modèles offrent aux décideurs des informations importantes qui peuvent les aider à optimiser leurs décisions en matière d’allocation de l’eau. Cette étude évalue l’impact des instruments économiques tels que les quotas, la taxe environnementale et le système quota-taxe, sur la durabilité de l’aquifère Mahdia-Ksour Essef ainsi que sur l’économie locale, tout en intégrant les projections climatiques futures grâce à la modélisation hydro-économique. En explorant divers scénarios de gestion de l’eau, l’étude fournit des recommandations pour améliorer l’allocation des ressources. Les politiques de quotas, ajustés en fonction de la recharge naturelle, ainsi que les taxes et le système quota-taxe sont examinés et comparés au scénario de statu quo. Les résultats montrent que les politiques basées sur les quotas permettent une reconstitution plus rapide de l’aquifère et génèrent des revenus totaux après taxes supérieurs à ceux avant taxes. Par exemple, sous le scénario de changement climatique le plus pessimiste, le quota de préservation de la ressource en eau pour les générations futures pourrait augmenter le niveau de l’aquifère à la fin de la période de simulation de 1,69 m. Ces politiques pourraient influencer les revenus agricoles, en favorisant des cultures plus rentables et résilientes à la sécheresse, telles que les olives et les amandes. Cette étude souligne l’efficacité des modèles hydro-économiques en tant qu’approches pour évaluer la gestion des eaux souterraines. Ainsi, elle oriente les décideurs vers des choix stratégiques favorisant la durabilité et l’efficacité, particulièrement dans un contexte de changement climatique et de surexploitation des ressources en eau.

The Middle East and North Africa (MENA) region is struggling with a continuous decline in water availability, attributed to climate change and variability, exacerbating the existing water scarcity. At the same time, factors such as population growth, urbanization, economic development and mismanagement further stress the scarce water resources. This study aims to assess the impact of climate and socioeconomic changes on the availability and use of water resources and related economic and environmental conditions in the MENA region at high spatial and temporal resolutions, in order to provide insights into cost-effective and sustainable water management options to reduce water scarcity. To do so, we apply a set of potential future climate and socio-economic change scenarios, based on combinations of the Shared Socio-economic Pathways (SSPs) and Representative Concentration Pathways (RCPs) and informed by a review of regional development visions and consultations with key regional experts. Scenario simulations are conducted using the hydro-economic model ECHO in combination with the hydrological model CWatM at subbasin and monthly levels for the whole MENA region. Results of this study shows the escalating deficit in renewable water resources and the rising water demand, exacerbating water scarcity across the majority of the MENA countries. Therefore, meeting the increasing water demand becomes an even greater challenge in the region. To address this challenge, our results underscore the need for a more efficient allocation of water resources among sectors and subbasins at the regional level and a shift towards more advanced water conservation and reliable water supply technologies. Keywords: Hydro-economic assessment, Water scenarios, Water scarcity, MENA region.