The Water, Climate, and Food Nexus

Water, as an increasingly scarce natural resource, is still a vital resource for both development and security. This resource is coming under an enormous strain because of a myriad of factors, including the increased demands of a growing global population and economy, environmental and climatic changes, and the irresponsible use. The decline of water resources is currently putting food systems under pressure. Indeed, the twin challenge is currently providing an ever-growing human population with sufficient and nutritious food, while facing environmental/resource limits and climate change. Thus, with the escalating water scarcity, a sustainable transformation of the global food system is unreachable without a revolution, especially in the area agricultural water use. In this perspective, the agricultural sector is being transformed to greater heights by new technological developments such as smart farming, precision agriculture, and climate-smart agriculture, which will enable this primary sector to move to a higher level of farm productivity, profitability, and resource-use efficiency while maintaining sustainability and fostering food security and resilience. This process remains dependent, however, on the extent to which different sectors involved in water resources management work in integrated and coordinated ways. This involves a shift in governance systems and the definition of roles and responsibilities for everyone engaged in the process of water resource generation, management, and usage. Against this background, the present introductory chapter presents the framework and content of this book, which addresses timely and future-oriented topics. In the first set of chapters, the water, food, and environmental/climate security nexus is explored theoretically and by reference to empirical research covering many regions and sectors. In another set of chapters, the impacts of climate change on water resources and water-stressed regions are identified along with their implications for food systems and security. Other chapters of the volume identify the emerging solutions to the nexus challenges, mainly adaptation and mitigation options, governance and management approaches, technological and economic solutions, innovative farming and water management practices, etc. Most chapters scheduled for publication are based on empirical research particularly done in water-constrained and climate vulnerable countries from Asia, Africa, and the MENA region and provide policy-oriented inputs and recommendations to guide change processes at multiple scales.

Water, food, and environment are not only essential components of human life and existence but are also important for the economy. Given their interdependence, it is increasingly imperative to study them from a nexus perspective. Water is essential for daily life, industry, and agriculture and originates from varied underground and surface sources. The decreasing quality of water due to anthropogenic activities—such as pollution induced by industrialization, unsustainable agriculture and the wide use of toxic materials—contributes to water insecurity worldwide. Moreover, the underground water is being over-pumped in large quantities across in many regions, which results in water scarcity. Biological and technological advancements including hybrid seeds, improved irrigation facilities, efficient fertilizers use, effective disease and pest control, and efficient farm machinery in agricultural sector globally have contributed to increase the food production. Also, progress is being made in terms of economic development and growth but the sufficient and quality food is not available to the entire population for many reasons, including access and governance issues. Increasing food prices, unemployment, lack of opportunities and consumption smoothing make it difficult for the poor to access sufficient food. The natural environment is also on the verge of deterioration and degradation due to anthropogenic activities. Over and inefficient use of natural resources and unsustainable development have harmed the environment, sometimes irreversibly. Hence, this chapter aims at analyzing the different dimensions of water, food, and environment from a nexus perspective for a better understanding of the linkages between them and thus guide public policies aiming at fighting poverty, food insecurity and vulnerability while promoting a healthy environment for present and next generations.

Water, both for human use and agriculture, is a concern in the Middle Eastern and North African economies (MENA), entailing risks and opportunities in these countries. Besides, fast-changing politico-socio-economic and environmental conditions make water security challenging for policymakers. Water security, coupled with food security, has become a distinct and more unnerving challenge than ever before. This chapter provides a detailed analysis of water scarcity, food security, and climatic challenges in MENA countries and provides a way forward in addressing these issues. In MENA countries, water shortage, food security, and environmental problems are intertwined. It is imperative to use water resources efficiently to ensure a sustainable environment, efficient (allocative) use of water, and obtain distributive justice, contributing to social contract or integration. This argument also includes delivering water input reliably and affordably to ensure cordial relationships between service providers and water users and help promote the renewed social contract. The climate of MENA is arid and near arid. The drought cycle is shortened from three years to annual and often brings floods. Thus, water security, food security, and environmental issues are more than ever-changing targets; however, some are within reach of humankind. A series of suggested solutions to the MENA region’s water resource management and associated problems exist. Implementing these solutions needs clear incentives to bring about water management changes, including conservation, allocation, and address some of the riparian issues and water conflicts among the MENA countries, such as the Nile and other basins. The MENA countries warrant better engaging the civil society (e.g., High Aswan Dam in Egypt) and water users, teaming millions of youths to make the solution work. The debacle of doable policies addressing water challenges can severely affect nations’ well-being and fragile political stability. Thus, the strategic question is ‘now or never.’ The MENA countries should act with urgent attention in strengthening water security, food security, and a sustainable environment instead of waiting for doomsday for impending water crises leading to ‘Water Conflict,’ quoting the saying of late United Nations Secretary-General Boutros Ghali that the “3rd world war will be on waters”.

The water-energy-food (WEF) nexus is a novel concept, which aims at integrating three key drivers of development and human security. Effective management of these three resources requires careful assessment of synergies, conflicts and trade-offs which are inherent in the nexus. In Kenya, the achievement of sustainable development goals relies on the management of these key resources. Climate variability and climate change bring uncertainty to water, energy and food situations in the country. Over 75% of agricultural activities in the country are rainfed and thus risky in the face of the poor temporal and spatial distribution of rainfall. Energy reliability is low in Kenya due to the dependence on hydropower sources which are prone to climate risks. This review highlights the importance of the WEF nexus in the face of climate change impacts. Climate adaptation mechanisms for building resilience in cropping systems, water service and energy provision are key elements for the improvement of livelihoods. It is imperative to address sustainably and holistically the three key sectors through policy, legal and institutional frameworks and initiatives. Assessment models and tools are developed to monitor the attainment of targets under WEF.

Climate change poses a global challenge, intricately linked to the intricate, long-term interplay among environmental factors and the dynamics of economics, society, technology, and politics. These interactions lead to notable repercussions at the regional level. This investigation utilizes data from nine campaigns conducted in 1990, 1995, 1997, 2009, 2015, 2016, 2017, 2018, and 2019 to evaluate groundwater quality in the Essaouira region within the context of a changing climate. The hydrogeochemical analysis reveals that the Cenomanian–Turonian aquifer’s groundwater exhibits mix facies such as Cl–Ca–Mg, Cl–Ca, Cl–Na, and HCO₃–Ca, with the Cl–Ca–Mg mix facies dominating along with Cl–Ca. Examination of correlations between major element concentrations indicates that groundwater mineralization is influenced by the dissolution of evaporitic minerals (halite, gypsum, and/or anhydrites) and carbonates (dolomite). Additionally, reverse ion exchange and marine intrusion, particularly in the Plio-Quaternary aquifer, contribute to the overall mineralization. The spatio-temporal analysis of groundwater quality in the study area demonstrates a gradual deterioration over time and space. Notably, the Essaouira basin emerges as particularly susceptible to climate change due to its reliance solely on meteoric waters for recharge.

Ensuring access to potable water for a substantial portion of the population, effectively managing and conserving this frequently overutilized resource, regulating agricultural and industrial water consumption, and safeguarding the natural environment constitute significant challenges, particularly in the context of developing nations. The primary objective of this investigation was to assess the influence of climate change on the hydrological patterns within the Essaouira basin during the time frame of 2020–2050. To accomplish this, the Rural Genius GR2M model was employed to simulate streamflows based on precipitation and evapotranspiration data. The Mann–Kendall and Pettitt tests were employed to scrutinize the temporal series for both their consistency and directional trends. The chronological sequence of potential monthly evapotranspiration (ETP), covering the span from 1978 to 2005, demonstrates an escalating tendency, denoting a 4.2% increase. This trend in potential evapotranspiration remains evident under different Representative Concentration Pathways (RCPs) of CMIP5 (Coupled Model Intercomparison Project Phase 5) scenarios, specifically 2.6, 4.5, and 8.5 RCPs, where the trend rates are measured at 1.9%, 1.5%, and 1.6%, respectively. The investigation into the correlation between precipitation and streamflows, from 1978 to 2005 within the Essaouira basin, establishes the presence of a causative relationship between these two variables. This relationship holds true across all regions subject to arid and semi-arid climatic conditions. The insights derived from these findings can provide a foundation for safeguarding and managing water resources within the Essaouira watershed, including the construction of upland reservoirs along the Igrounzar, Zelten, and Ksob Wadi, enhancing the basin’s overall water management strategy.

In recent decades, the specter of global warming has loomed large, emerging as a substantial and impending threat to the well-being of the global populace. Within the context of nations particularly susceptible to the repercussions of climate change, Morocco, notably its regions characterized by arid and semi-arid climatic conditions, assumes a prominent position as one of the most exposed to vulnerability. To gain deeper insights into the intricate interplay between climate change and the availability of water resources, a comprehensive approach has been adopted. This approach encompasses a climatological analysis encompassing factors such as rainfall and temperature, alongside an exploration of groundwater levels, salinity, and isotopic methodologies. A meticulous examination of the annual precipitation patterns has been conducted, drawing upon the graphical representation offered by the Nicholson rainfall index. Furthermore, this investigation has employed statistical tools, notably the Pettitt and Mann–Kendall tests, to probe the nuances of these climatic shifts. The results that have emerged indicate an overarching negative trend in the basin, signifying a reduction in annual precipitation ranging from 12 to 16% over the span from 1978 to 2015. This decline in the average annual precipitation levels is juxtaposed against a concomitant escalation in temperatures, manifesting as a highly substantial warming effect. Specifically, this warming amounts to 1.2 °C in the downstream segment of the study region and 2.3 °C in its upstream counterpart, a phenomenon that underscores the pronounced continentality of temperature patterns in this geographical area. In light of these findings, there exists a compelling rationale for the inclusion of stringent local and global policies aimed at mitigating the emission of greenhouse gases, fostering the utilization of clean and renewable energy sources, and engendering awareness and education among the populace. These endeavors are of paramount importance, serving to expedite the adoption of adaptive behaviors capable of addressing the challenges posed by a warmer and drier climate. This is particularly pertinent for individuals inhabiting regions characterized by semi-arid, arid, and Saharan climates.

Climate change is a reality today. The most important indicators of the climate change are the long-term changes in the spatial and temporal precipitation and temperature patterns. It is being felt more and more over time by extreme weather events and changes in temperature and precipitation trends. Data collected about the temperature and precipitation patterns provide important clues about climate change. For this purpose, different statistical analysis methods are used. Since hydro-meteorological observations are data covering a series of time, they may be intermittent, short-term, irregular, and skewed. For this reason, homogeneity tests were applied before the statistical analysis. In this study, the Standard Normal Homogeneity test, the Mann–Kendall and the Spearman Rho tests from the non-parametric test groups, and the Linear Trend test from the parametric test groups was applied to all data. Applications were made on the temperature and precipitation values obtained from the observation stations that show slight differences from each other and represent three sub-climates in the city of Erzurum, Turkey, which has a semi-arid main climate. It is seen that there is an increase in the temperature trend and a decrease in the precipitation trend for all three stations. The statistical significance of the change in temperature and precipitation trends requires urgent action to be taken against climate change. It also gives an idea about the dimensions of adaptation studies.

Groundwater serves as a vital source of potable water for domestic and drinking purposes in various regions globally. However, rising sea levels have led to the encroachment of saltwater into coastal underground aquifers, resulting in a degradation of water quality over time. In the context of the hydrogeochemical examination conducted, it was observed that the groundwater within the Plio-quaternary aquifer exhibits a composition characterized by Cl–Ca–Mg and Cl–Na elements. Specific ionic ratios, such as Br/Cl (approximately 1.5–1.7‰) and Na/Cl (approximately 0.86), in addition to relatively weak values for Mg/Ca and SO₄/Cl ratios, signify the initiation of seawater intrusion into the freshwater reserves of the Plio-quaternary aquifer within the Essaouira basin. This incursion of seawater is substantiated by ionic ratios and is further validated through stable isotopic analysis. By leveraging the combined information from oxygen-18 contents and chloride concentrations, the degree of mixing between seawater and freshwater in the Plio-quaternary aquifer is estimated to range from 12.8 to 15.9%. Furthermore, the stable isotopes approach has shed light on the source of recharge for the Plio-Quaternary and Turonian aquifers, indicating that these aquifers are primarily recharged by Atlantic-origin precipitation with limited evaporation effects. However, it is evident that these freshwater resources have undergone contamination due to the intrusion of seawater.

Groundwater is one of the most imperative natural resources utilized worldwide for a variety of purposes. Agricultural, domestic and industrial usage of this is increasing manifold. The available surface water resources are not enough and are inadequate to meet the drinking and irrigation requirements of the crops. Groundwater has more essential advantages as compared with surface water. Climate change is affecting the global natural resources, particularly the water cycle consequently groundwater resources are observed to be compromised worldwide. Groundwater flow models could be very useful tools for the efficient management of groundwater resources if properly calibrated and validated. The models can help to manage the aquifer system and its related features in realtime. Different future scenarios can be developed using global and regional climate model data to simulate the impact of climate change on groundwater resources. The climate models data can be downscaled using dynamic or statistical techniques however the authenticity and reliability of these downscaled values are still questionable. For the assessment of climate change impacts on groundwater resources, it is imperative to understand the extent and magnitude of groundwater vulnerability to droughts, over-exploitation as well as deterioration in its quality. To understand the spatial and temporal availability of groundwater a better quantification of the regional water budget is also required. This information can be a good source of evidence for the groundwater managers dealing with present and future climate change regimes. The future sustainable availability of groundwater is highly dependent on long term climate trends and their possible implications on groundwater recharge and water level fluctuations.

Groundwater is vital for water supply and environmental protection, especially in semi-arid and desert regions. An integrated assessment, focused on the combined use of Water Quality Index (WQI), Irrigation Water Quality Index (IWQI), geochemical and isotopic (δ¹⁸O, δ²H and δ³H) tools, was performed in the Cenomanian–Turonian aquifer during the campaigns 2017, 2018, 2019, and 2020. Hydrogeochemical analysis reveals that the groundwater is of mixed Ca–Mg–Cl, Ca–HCO₃, Ca–Cl, and Ca–SO₄ types, with a dominance of the first type. The analysis of the abundance of the main cations and anions shows the dominance of Ca²⁺ > Na⁺ > Mg²⁺ > K⁺ for cations and the dominance of Cl⁻ > HCO₃²⁻ > SO₄⁻ > NO₃⁻ for anions. The WQI in the Cenomanian–Turonian aquifer was divided into 32.8% (good areas), 44.3% (poor areas), 21.3% (very poor areas) and 1.6% (areas unsuitable for consumption). The IWQI showed that 43% of the studied samples have a high to severe restriction level, while 57% of the studied samples were placed in the low to moderate restrictions for irrigation use. The piezometry of the study area showed that the water flows generally from northeast to northwest and northeast to southwest. Groundwater mineralization in the Cenomanian–Turonian aquifer system is controlled by dissolution, including dissolution of evaporite minerals and reverse cation exchange. Stable isotope signatures (δ¹⁸O, δ²H) indicate that the groundwater samples are of meteoric origin without significant evaporation. The most of spring has tritium < 1TU. This could be explained by a reduction in annual precipitation recorded in the study area. The recharge altitude of the aquifer was estimated between 375 to 1275 m, following an altitudinal gradient of 0.26% per 100 m.

A severe natural disaster, drought affects the economy, the ecology, and many other areas on a global scale. For the Potwar region (PR) in Punjab, Pakistan, drought indicators (DIs), including deciles, the Standard Precipitation Index (SPI), and the Reconnaissance Drought Index (RDI), were computed using the DrinC programme. Drought conditions were predicted for the next 12, 9, and 3 months. Eight of the last 39 years have seen a severe drought, according to DIs created using the deciles technique, and such cycles repeat every 2–7 years. Similar trends were visible as deciles in both the RDI and SPI indices. However, for RDI and SPI, the extremely dry and severely dry classes only persisted for two years, whereas the years that affected the other deciles were typically and moderately dry. Deciles are less useful for assessing the severity of the drought than SPI. Based on a regression study that shows a connection between the RDI and SPI indices, the yearly RDI may be predicted if the first three months of precipitation are known. This research can help future development strategies tackle sensitive drought occurrences, their mitigation, and their socioeconomic repercussions.

Climate change has significant impact on all components of the hydrological cycle. Warming scenarios and increased uncertainty in rainfall behavior may lead to increase in crop water requirements and decrease in its availability for irrigation. As a result, ground water resource is being depleted at alarming rates in many regions of the earth, especially south-east Asian region. Due to increased frequency and intensity of extreme weather events, agriculture has become highly vulnerable to climatic risks. Such scenarios are endangering food security for the burgeoning population along with over-exploitation of natural resources. Hence, most of the research is oriented towards improving/optimising crop water productivity rather than yields. Under such conditions, climate-smart agriculture seems the viable option to manage climate change impacts on water-use efficiency. On-farm water management, rainwater harvesting, groundwater development, advanced techniques of irrigation, breeding for resistance to droughts and floods as well as construction of dams for water storage are some of the practices which are immediately required to manage water scarcity. Improving soil moisture retention, changing cropping calendars, encouraging crop diversification, irrigation management such as deficit irrigation, supplemental irrigation, alternate wetting and drying in rice, etc. are very important on-farm practices for enhancing crop water productivity. In addition to this, some policy measures such as climate proofing structures, reallocation of water among different sectors, and crop insurances are also required to be implemented by governments. Improved weather forecasting can play very crucial role to minimize climatic risks in agriculture. Crop simulation and hydrological modeling are other techniques which can assist in tactical decision making for improving crop water productivity and better management of water resources. In addition to this, remote sensing and geospatial techniques can also be used successfully for improved hydrological monitoring at regional level. Hence, there is a dire need of taking quick actions to enhance water-use efficiency and save this precious resource for sustaining agriculture and attaining food security in future.

Recently, as the world facing a water shortage due to climate change, a growing number of countries are considering irrigation using reclaimed water as an appropriate solution to secure and enhance agricultural production. Among the African countries affected by water stress, Algeria is in the category of the most water-stressed countries. In this chapter, the water quality of the treated wastewater produced from Wastewater Treatment Plant (WWTP) of Ain Temouchent, a semi-arid region located in the northwestern part of Algeria, is determined including physico-chemical parameters, heavy metals and microbiological contaminants. Except of phosphate ions (PO₄⁻³), the other physico-chemical parameters and heavy metals were below the recommended norm of WHO, FAO and Algerian standards for irrigation purposes. However, the results of the microbiological analyses indicated that the number of fecal coliforms and intestinal nematodes are above the WHO norms for treated wastewater intended for irrigation. On the other hand, according to Algerian norm, the irrigation of the fruit trees through drip irrigation technique is likely to reduce the risk of contamination while preserving the health of the consumers.

Water has been one of the main factors determining the fate of civilizations for centuries. Today and in the future, water scarcity is one of the biggest problems for mankind. Precipitation water harvesting can be defined as the collection and accumulation of rainwater and runoff water, the supply of water required for plant and animal production, and the supply of water required for domestic consumption. The fact that the water obtained is free of charge, protecting natural water resources can be easily integrated into the existing water network system. In addition, low operating and maintenance costs make precipitation harvesting extremely attractive for the management of water, which is a scarce resource. With the collection of precipitation water, purposes such as preventing soil erosion and floods, providing quality irrigation water, feeding groundwater, and saving network water can be achieved. Precipitation water harvesting is a water supply method that has provided drinking water to many historical cities since ancient times. Archaeological findings show that rainwater harvesting dates back to 6000 BC. Precipitation water harvesting has been practiced since humans began to live and grow crops in arid areas. While in many arid countries a large part of rainwater is lost through evaporation or turning into wastewater, worldwide awareness and importance of rainwater harvesting are increasing. This chapter describes the elements of roof precipitation water collection systems and includes the basic principles that should be considered when planning.

Water is a basic necessity, without which no individual or nation can survive. Every nation, therefore, needs to ensure its water security, which encompasses all dimensions of human health, livelihood and well-being, and food and energy production. All industrial nations first strived to ensure their water security through early substantial investments in infrastructure, institutions, and capacity to manage water and wastewater. Singapore is an important case to understand the political economy of water security. With its high dependence on neighbouring nation for water supply and with limited land to collect and store rainwater, Singapore encountered drought, flood, and pollution since its independence in 1965. Over the years, Singapore adopted integrated, effective, robust and cost-efficient approaches with strategic investments in research and technology to treat, recycle, and supply water. Today, the country is recognized internationally not only as a model city for integrated water management but also as an emerging global hydro-hub. Touching on the causes of water insecurity in the world today, this chapter delineates the Singapore story of how ‘water scarcity’ in the nation has been transformed into ‘water opportunity’. To bring critical insights, the chapter also compares the Singapore case with two other similar nations: Saudi Arabia and Israel.

Water management is the biggest challenge of twenty-first century being confronted by Pakistan due to inadequate water management practices, insufficient storage capacity, irrigation inefficiency, population explosion, over-exploited ground water, climate-induced water stress, and India’s water hegemony as upper riparian. Continuing mismanagement of water resources is resulting in increasing water insecurity in the country. Pakistan is already a water stressed country which has not optimally managed its available water potential through adroit water conservation and storage strategies. The country would not be water secure until it implements stringent water management measures in addition to building dams. In this context, the study endeavours to answer the question as to why adequate water management practices are essential for the future water security of Pakistan as well as its socio-economic development. The study also highlights challenges faced by the water sector in the country and concludes with the doable policy recommendations.

Rivers do not follow political borders while flowing through their natural courses. Transboundary rivers can be the cause of water conflict between nations. Treaties and agreements have been made to settle these conflicts. In the Indian sub-continent, western rivers are becoming a matter of concern for Pakistan in terms of water quantity. Various dams are constructed by India on western rivers and many more are under construction/planned. In this research work, a comparison has been made between the viewpoints of both countries regarding transboundary interventions. India’s point of view is that variations in river flows and water shortages in Pakistan are because of her own negligence. India is doing nothing to violate the Indus water treaty and is utilizing the water allocated to her on western rivers. According to Pakistan, India is stealing water supplies from Pakistan and constructing its water-controlling structures only as a political exercise to improve political power. Maintenance of transboundary aquifers and groundwater management, transboundary cooperation in watershed management and integrated water resources management can lead to sustainable development between both countries. The outcomes of this work will provide information related to transboundary conflicts, treaties, and future concerns to the researchers and policymakers.