Keywords

1 Background

With a population of more than 8 billion, escalating economic crises, resource overuse, climatic change, and uncertainty, as well as increased hunger and poverty, the globe is experiencing a difficult time. These obstacles are associated with the economic, social, and political problems and instability that both the current and next generations must deal with. In an effort to determine the forms of interconnection that exist amongst those systems, several nexus combinations, such as energy, water, food, trade, climate, and population growth, are being analyzed [1]. Recognizing the issue’s depth and diversity resulted in the creation of those nexuses. This chapter examines the connections between energy, water, and, food and provides a framework for understanding this nexus that may be used to address any interfaces and more fully assess these interactions. Food, energy, and water security are all closely connected [2]. In non-scientific words, water is needed for food production, energy is needed for water extraction, purification, and transfer, and water is needed for energy generation [3]. Financial markets and people, climate changes, and environmental challenges all strengthen the already-existing relationships between the three systems [4]. A conceptual model of the nexus with the existing connections between water, energy, and food is shown in Fig. 1. The elements that influence the nexus are also presented, including growing economies, climatic change, population growth, global commerce, and governance. The below sections will highlight further each component and its importance.

Fig. 1
A flow diagram links energy with pumping water treatment to irrigation. Irrigation connects to food, bioenergy, and back to energy. Water links to production cooing and transport and irrigation. Also, energy links to water and food via a single chain.

Nexus of water, food, and energy and key components

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2 Nexus

Nexus (from the Latin nexus, meaning “relation, connection”) has diverse meanings in different fields, but generally speaking, it refers to the central place of every link when taken as a whole [1]. Natural ecosystems are crucial for development because they not only support the water, agricultural, and energy sectors but also protect biodiversity in flora, fauna, and landscapes, support tourism, foster economic growth, make it easier to adapt to climate change, and help to mitigate it. However, they are also in danger of extinction. Due to population increase, industrialization, urbanization, economic development, and environmental issues [5], there are challenges in ensuring adequate water supply and water security. These challenges include rising energy and food needs. The stress placed on natural ecosystems also increases. Countries will be better able to protect ecosystems and reinforce their access to water, energy, and food with the help of reduced negative interactions, the development of synergies, increased efficiency, and improved management systems in a variety of sectors. The basic objective of the nexus is to better management of resources. So the nexus is the interconnection of resources between food, water and energy in the natural ecosystem [6].

3 Food

Food systems include all of the manufacturing, transportation, and consumption processes that connect individuals with the food they consume, as well as the systemic effects on the environment and society as a whole. The manufacture, preparation, and transportation, as well as individual food intake preferences, are all activities that are part of the food system (e.g., diets and waste) [7]. Over the previous 50 years, livestock productivity has expanded by 2.5 times while agricultural production has more than tripled. More than 50% of the global crops are currently produced by only major countries: China, Brazil, Indonesia, India and the United States [8]. However, only four crops, rice, wheat, soybeans, and maize account for more than 56–57% of calories or 60% by protein content of the world's present food supply. Food nexus are becoming more and more globalized; today, 23% of food calories are exchanged worldwide, and 85% of countries import food to fulfill local demand [9]. Food consumption has recently increased globally, partly due to rising incomes and population growth. With an 8 billion massive populations, individuals can spend more on better food with increased protein and calorie consumption. All of this increases the impact on the environment’s resources. People may find it more challenging to reach their goals for lowering greenhouse gas (GHG) emissions as a result of the increased usage of animal products. This alleviated hunger for an estimated 123 million people in poor countries. Yet, significant dietary shortages still exist, with around one in seven individuals consuming insufficient carbohydrates, protein, and even supplementary without availability to vital micronutrients [10].

4 Water

Water plays a crucial role in sustainable development as it is the basis of life and livelihoods [11]. The goal is to ensure accessibility and continuous supply of water for all, effective water management is essential. The future of humans, the planet, and the global economy all depend on water [12]. A living income and secure working conditions may guarantee individuals a stable income and open the door to greater social and economic progress. Just 12% of the world's population utilizes all of the water available, making it one of the most precious and limited resources in existence. Already, one-third of the world's population resides in regions with insufficient or inadequate water supplies. UN water-severe nations include those with less than 200 m3 per capita per year.

Freshwater is essential to human populations for many purposes, including drinking, home use, and industrial and agricultural productivity. However, compared to other human uses of freshwater resources, agricultural uses dominate them by a wide margin. A little over 86% of all society water usage goes toward the production of food, including crops and cattle, while in some places, particularly in significant urban areas, domestic and industrial uses might predominate. Thus, ensuring water supplies for agriculture is one of the most significant challenges in the current era. The distribution of rainfall across the globe is predicted to be disrupted by climate change, which would also likely increase worldwide precipitation and worsen the already acute water shortage. Water precipitation will probably become more irregular in terms of timing, which will make droughts and floods more in the future to occur. In certain cases, groundwater consumption is reducing water reserves that have built up, attributed to a phenomenon known as “groundwater mining,” which involves the extraction of water resources. The aquatic environment is destroyed and important aquatic species go extinct as a result of excessive water removal from rivers and streams. In addition, other industries including mining, manufacturing, and energy generation significantly raise the human need for water [1].

5 Energy

Energy is needed for human activities to run industry, transport, heat, and cooling systems [13]. The primary sources of energy in earlier centuries were the burning of wood and moving water by animals’ power to run small mills, both of which needed land and access to water for the generation of energy or making food. Hence, the availability of land and water limited the generation of energy in preindustrial times. With machines powered by fossil fuels that required almost no water or land, the industrial revolution gave people access to electricity. Fossil fuel machines and engines based energy (oil, coal, and gas) importance increases at this time [14]. After 1950, this shift to a high-energy society was accompanied by significant socioeconomic changes, such as an increase in agriculture, acceleration of industries, urbanization, economic growth, and demographic growth. Yet, the benefits of our growing dependence on fossil fuels are derived from the cost of using a large portion of the oil and gas, limiting the future production of such energy sources [15]. The use of fossil fuels raised the amount of CO2 in the atmosphere at the same time, having a significant impact on the planet’s climate. Now the world is facing a severe energy shortage and the available energy resources are depleting at a high rate [16]. The demand for energy is further raising with an increase in the global population and at this stage, about 2.8–3 billion people are living without energy. The continuous use of fossil fuels contributes significantly to increases in greenhouse gas emissions, pollution, and other related environmental and health issues. More efficient strategies for obtaining energy from renewable sources, such as wind, solar, ethanol, and biogas have recently been under consideration for future energy [17, 18].

6 Nexus of Food, Water, and Energy

The term nexus is used for the connection between the three components of energy, food, and water. To produce food for population consumption, a lot of energy and water are needed. Energy is used when water is transported to your home and purification processes [19]. Water is used for running safely different power plants and coal, oil, and gas production. Certain food crops are also used to make fuel for transportation. There are implications for the economy, the environment, and public health when these three systems are at odds with one another. Drought, oil spills, and rising food costs are just a few examples of events that highlight their connections. The processes, assets, and people involved in getting food from the farm to the table are all part of the food nexus. The food nexus includes marketplaces, feedlots, trucks, fertilizers, markets, and even our own kitchens. A water nexus provides water for human use, including drinking, irrigation, and industrial uses, and processes wastewater to safeguard environmental and public health. The main apparatuses of the water transport are pipes, water towers, watersheds, treatment facilities, and estuaries. An energy nexus is made up of all the processes required to produce and distribute fuels, as well as to generate and distribute electricity. The energy system includes power plants, solar panels on rooftops, transmission lines, coal mines, and oil refineries. Understanding how to produce enough food, provides sufficient energy, and guarantee that everyone on the earth has access to clean water is important. Governments, enterprises, and industry are not primarily to blame for this, though. Every one of us individually has a crucial role to perform. Our actions and decisions regarding energy, food, and water have a significant impact on one another and on the ecosystem. Our chances of creating a sustainable future are brighter as more of these links, or “nexus understanding,” are considered [7]. A schematic flow and interdependencies among the water, energy, and food is concluded in Fig. 1.

6.1 Nexus of Food and Water

Food demands may be met directly or indirectly depending on the availability of water in the area. In terrestrial ecosystems, water is necessary for all primary production or plant development. Hence, there is a close connection between the availability of water and food production. In many regions of the world, food yield is constrained by the availability of water. Food yields will increase when water is gathered from bodies of surface and groundwater and used for irrigation. For the purpose of producing food, each person consumes 1,200 m3 of water annually. This amount, which is also known as a person’s “water footprint,” normally varies based on diet between 600 and 1,800 m3/year per person. Agriculture is the main consumer of about 71% of the world’s water and is anticipated to further increase in the coming decades. In addition to the growing water shortage, the agricultural industry must produce roughly 50% more food by 2050 double the amount produced currently. It is essential to streamline the farming process. Growing the same crops with less water by employing more effective technology locally is a major problem. Realizing that different countries and regions of the world have varying levels of technology development and financial capability to adopt newer, more effective techniques is important. It is important to comprehend the possibility of redistributing food produced all over the world in a way that makes the best use of rain-fed water. In order to produce the same amount of food, results in saving both surface and groundwater [1].

6.2 Nexus of Water and Energy

As significant users of one another, energy and water are interconnected. Freshwater pumping, water management, drainage, water treatment, desalination, and water distribution in farms and towns all require the usage of electricity, which makes the water system a significant energy consumer. Groundwater pumping requires a lot of energy, yet its source has a big impact. “Groundwater supply from public sources takes 1,824 kilowatt-hours per million gallons, or roughly 30% more electricity per unit than supply from surface water, principally because a larger requirement of raw water pumping from groundwater systems is needed [4]. The fact that transporting things over water uses energy as well is typically ignored. Water is needed for the extraction and purification of resources, transportation, refrigeration, and materials exploitation. Water resources are also needed even for the waste biomass disposal consuming energy. For example, the largest water withdrawal in the United States and the majority of other industrialized countries is for cooling power plants [6]. The technology utilized in energy- and water-demanding activities greatly influences how dependent one system is on the other. In order to reduce their dependency on costly and increasingly limited fossil resources, current policies are looking for alternate energy sources. When the sustainability of these alternatives is looked upon, controversy results. Among those sources are nuclear and biofuels. The most water-intensive source of fuel is biofuel, with an average water consumption of over 1000 gal/MMBtu, which is significantly more than that of other liquid fuel alternatives. The most water-demanding thermoelectric technique is nuclear energy, which, depending on the technology utilized, uses 200–800 gal/MWh. To alleviate any stress that water and energy systems are experiencing as a result of existing practices, this part of the nexus has an institutional and policy dimension that needs to be adequately conveyed through a common global agenda. It is necessary to investigate the possibility of depending on renewable natural resources like solar and wind power, which could help in finding a solution to the problem of fulfilling rising needs without putting further burden on the nexus. Energy and oil production requires a water supply, and a water supply requires energy. Energy and water are both precious resources that will cause increasing concern in a world that is changing quickly. Our dependence on water-intensive fuels is likely to rise as a result of new energy technology employed to “decarbonize” the economics of commercial civilizations, furthering the dependency between energy extraction and water resources. Water availability may cause problems to current energy processes, and it is becoming more generally recognized as a factor influencing the physical, economic, and ecologic practicability of energy production projects. Water shortage is affecting the location and technology of energy projects in China as well as forcing the closure of coal-fired power stations in India (IEA 2015). (IEA 2015). Hydropower’s contribution to overall energy generation in California has fallen from 30 to 5% as a result of the drought. Another nexus problem for the energy-water nexus that is rapidly expanding is dam development. On the one hand, building a dam can lead to both substantial economic benefits and the generation of renewable energy [1, 2, 6].

6.3 Nexus of Food and Energy

Food processing involves a number of energy-intensive processes, such as running agricultural equipment and preparing, packaging, and refrigerating food. As a result, food is somewhat connected to gas emissions due to the energy used in producing it. Food-related activities account for between 19 and 29% of all anthropogenic greenhouse gas emissions worldwide, but compared to other food-related activities, agricultural production’s much more responsible for the majority of both direct and indirect emissions. The use of food crops as a feedstock for the manufacture of biofuels is one of the most evident ways that food and energy are intertwined. The requirement for water in the food and energy sectors is frequently influenced by competition for land and water, which results in a variety of interactions. Energy prices can be linked to food prices due to the increasing cost of agricultural cultivation and transportation, which was particularly evident with the rise in demand for first-generation biofuels as a result of increased oil prices. A certain level of dependency on energy from renewable sources as an alternative to fossil fuels has been mandated by recent energy laws in an effort to lower the rising atmospheric CO2 concentrations. The outcome is that bioethanol and biodiesel are increasingly mixed with gasoline and diesel. Food crops are used for first-generation biofuels production, second-generation biofuels from cellulose-rich wastes biomasses, and algae can be used to produce third-generation biofuels. The first generation of biofuels is what is currently most frequently used. Maize is mostly used to make bioethanol, whereas soybean, rapeseed, and palm oils are commonly used to make biodiesel. The majority of bioethanol is consumed domestically, although at least one-third of the world’s biodiesel is made available through international trade, primarily through the trading of palm oil [1, 2, 6].

6.4 Combine Nexus of Food-Water and Energy

The demand for food is expected to rise by 35% by 2030 due to the world's expanding population. Agriculture and ecosystems support food production. Crops and animals are examples of agricultural output, and fisheries and forests provide ecosystem products [20]. To feed the entire world's population by 2050, agricultural productivity is predicted to need to rise by almost 70%. Improved automation, increased fertilizing, and effective irrigation are all necessary for such a growth in productivity, which typically entails increased water and energy use. Producing, distributing, trading, and gaining access to food are all influenced by affordability, distribution, availability, safety, and dietary preferences. Humans obtain their fresh water through rainfall, streams, rivers, reservoirs, lakes, and aquifers. Water is stored, delivered, and controlled by hydraulic structures called reservoirs for a variety of purposes. The production of non-renewable energy, which mostly consists of fossil fuels like coal, petroleum, oil, and natural gas, is still surpassing that of renewable energy, which is primarily produced by the solar and wind. When fossil fuels are used for energy, greenhouse gases are released, which causes air pollution (GHGs). Moreover, there are biomass, geothermal, nuclear, and hydroelectric sources of energy (biofuels, bio-power, traditional fuels, etc.) [1, 2, 6]. A water, food, and energy nexus system’s components are interdependent; any changes in the sources and rates of consumption of one of these resources will have an impact on the other two. For instance, the quantity of agricultural production, the kind of crop chosen, and the method of irrigation all rely on the accessibility of energy and water sources. The interactions between water, food, and energy include the use of energy for transportation, thermal sterilizing, food preparation, and cooking. In opposed to this, energy is used for pumping, collection, purification, storage, and delivery. Food production, transportation, washing, food processing, preparation and cooking all use water. Similarly, water is utilized in different industrial units for cooling, and electricity generation (power plants), etc. It is urgent and crucial to realize the interconnection of water, energy, and food as well as the effects of human consumption on all of these resources in the ecosystem. Sustainable development cannot be accomplished without the provision of adequate water resources, clean, renewable energy, and food supplies. To optimize the fundamental advantages and minimize or eliminate negative effects from human dependency on water, energy, and food consumption, the water, energy, and food nexus need to be understood and managed appropriately [21]. The essential elements in the water, food, and energy nexus are given in (Table 1).

Table 1 Elements involve in energy, food and water nexus
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6.5 Sustainability

The consideration of whether and for how long humans will be able to produce sufficient food to nourish every human being with the finite resources already available on the planet to provide food security. Because of this, the number of humans is expanding more quickly than can be fed. As a result, the population will soon outgrow the planet’s capacity to sustain it through food production, which cannot keep up with the population growth. Moreover, an increase in population may result in the unsustainable exploitation of natural resources. There is, however, no concrete proof to date that the availability of resources internationally limits population increase. Experts so usually ignore the impact of resource depletion, but they do model population increase as the outcome of an imbalance between fertility and death rates, which are influenced by social variables like health care and women's access to education, employment, and empowerment. The green revolution, which introduced new cultivars, irrigation systems, and industrial fertilizers, is an initiative to ensure human food security in the future. The industrial revolution brought forth advanced farming, processing, storage, and transportation systems. Global trade enables food-insecure areas to depend on extra production that exists in other parts of the world. Without really boosting the planet's maximum capacity, this “trade revolution” has decreased local food deficiencies by promoting greater global interdependence within the agricultural system. After decades of affluence, mankind is now again facing severe food crises with wide-ranging effects as agricultural yields are slowing in many areas and the safety margins associated with local redundancies in production are being reduced. Using a concept from the food revolution, it is still feasible to increase crop productivity in developing countries where there are still significant yield shortages as due to insufficient investment [1, 2, 6].

Growing population, income generation, and rapidly increasing living standards will result in an increase in future demand for water, energy, and food, posing serious challenges to the sustainability of natural resources and environmental preservation. Sustainable development goals (SDGs) for guaranteeing water and sanitation for all, food and nutrition security, cheap and sustainable energy, and addressing climate change and its effects underline the importance of the environment. The interactions between water, food, energy, and other necessary components, with shocks factors for sustainable ecosystem and life, is shown in (Fig. 2).

Fig. 2
A flow chart links to air, land, and water. In the middle sustainability of water food and energy has 8 shocking factors. It includes an increase in population, growth in living standards, climate, agriculture etcetera.

Graphic illustration of the water, food, and energy interactions among different components, the shocking factors for sustainable ecosystem and life

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6.6 Globalization and Nexus Security

Global scales are used to regulate energy and food systems. This is primarily due to integrated global markets that enable international trading in a variety of food commodities, including grains like wheat, maize, and rice, as well as soybeans, meat products, and liquefied natural gas and coal. These energy carriers also include liquefied natural gas and coal. Other forms of energy (such as solar and wind power, as well as some types of biomass energy) may be traded locally, but they are not truly global commodities. This is also technically true in the case of water, despite the fact that there are substantial “virtual” flows of water that are contained in manufactured items that are sold internationally, including food products. Oil continues to be the most important fossil fuel in the world’s energy balance, especially as the preferred fuel for transportation [22]. Significant amounts of water are needed by the energy system at many points along the energy production and consumption chain, including primary extraction, processing/transformation, power generation, and indirectly in the development and maintenance of energy infrastructure. Security issues related to energy, food, and water all exist on a global scale [23]. The primary triggering factors for the nexus are: (1) harsh weather events, such as droughts and floods; (2) increases to the oil price; (3) spikes to the price of food; (4) political turmoil; and (5) economic speculating in commodity markets [1, 2, 6].

The dangers and vulnerabilities that rural residents confront can be very different from those that urban residents face. This is partially due to the fact that much of the “upstream” end of the value chains for energy, food, and water tends to be located in rural areas, whereas most of the processing takes place in cities and towns. Changes in the climate and variability pose a serious threat to rural communities, particularly in the case of rainfed agriculture. The main nexus risks in urban areas are caused by the extensive, interconnected infrastructure (such as powerlines, roads, and pipes) required for the distribution of energy, food, and water, as well as by the wastes and emissions produced by consumption patterns that are typically more intensive than in rural areas. There are various types of positive loops of feedback, including rapidly deteriorating geopolitical tensions that can exacerbate nationalist feelings, which in turn can put food security in danger (for instance, if nations restrict food exports or participate in land grabbing). Extreme weather events brought on by climate change increase the risk to water security, which might limit hydropower production and push nations to rely more heavily on fossil fuels, which worsens climate change [1, 2, 6]. Climate change-related extreme weather events may cause a jump in food prices, endangering food security and leading to increased use of fossil fuels in agriculture, which in turn may increase greenhouse gas emissions. The detailed interconnection of all these factors both in positive and negative ways is depicted in Fig. 3. Whereas the risk factors and linkages between water, food, and energy is shown in (Table 2).

Fig. 3
A flow diagram links the security of energy, food, and water. It includes other linked components in between, ecological disruption, change in climate, increase in demand, etcetera.

The primary nexus linkages are denoted by green arrows. The negative effects of a factor on other drivers are indicated by red arrows in the energy-food-water diagram

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Table 2 The risk factors and linkages between food-water and energy
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7 Future Security and Viability

In the future, new strategies for global food, energy, and water security may benefit from an integrative approach intended to enhance the availability of food, access, and nutritive values while improving the accessibility to affordable, clean, and sustainable power (e.g., based on solar energy, hydropower, or wind power) [24]. Furthermore, a safe food, energy, and water system will combine a renewable source of resources, ensure environmental load and supply, and restore ecosystem services [25]. The food, energy, and water systems will need to reverse the current trend of increasing security vulnerabilities and strengthen their resilience to climate disruptions, population change, and consumption patterns. The increasingly rich population's demand for food and energy will barely be managed to meet the planet’s restricted land and water resources unless we transform the food, energy, and water nexus [1, 2, 6]. There is a need for complete rethinking in order to develop a comprehensive strategy for food, water, and energy security based on increasing production and stabilizing demand. There is broad agreement that efforts to increase food production in presently cultivated areas are necessary to prevent additional agricultural expansion, the implications of which would be significant and distasteful for natural systems and operations. Many rural populations in low-income nations cannot afford to invest in modern agricultural technology (irrigation infrastructure, machinery, fertilizers, and other inputs), which is necessary to increase crop yields [26]. Foreign firms or foreign-domestic joint ventures are likely to take advantage of the profit opportunities offered by underperforming agricultural land if neither local land users nor domestic investors are able to increase crop yields in years of rising crop prices [27].

The maximum possible yields of existing crops can be increased by engineering crop varieties with improved harvest index, water use efficiency, photosynthetic efficiency, or drought tolerance. Advanced molecular and synthetic biology technologies could be used in the green revolution to enhance the mechanisms for sunlight energy conversion, light capture, and carbon intake and conversion. New crop types and other genetically modified organisms are frequently created using genetic engineering technologies. Transgenic approaches allow for more exact genetic alterations by adding particular genes from other species to enhance crop production, in contrast to conventional breeding procedures and artificial selection for desired qualities (e.g., drought tolerance and insect and herbicide resistance). New crop types and other genetically modified organisms are frequently created using genetic engineering technologies. Transgenic approaches allow for more exact genetic alterations by adding particular genes from other species to enhance crop production, in contrast to conventional breeding procedures and artificial selection for desired qualities (e.g., insect resistance, drought tolerance, and herbicide resistance) [1].

By transgenic methods, introducing specific genes in organisms that do not already have a copy of those genes, such as changing the fat content in goat’s milk and reducing saturated fats in dairy products, can be used to induce genetic modifications in livestock species. In vitro culture of animal tissues in the lab could meet the growing demand for meat. By producing better meat products, these techniques could significantly decrease exposure to dietary pathogens and cardiovascular illnesses. In vitro meat manufacturing would also address ethical issues with animal welfare. Crop plants are widely thought to require soil in addition to water, nutrients, and light for their growth. Plants can, however, be grown in water with the right mineral additives instead of soil. This method, often known as hydroponics, can be applied both inside and outside, in recycling and flow-through systems) [1]. The key benefits of hydroponic farming over soil cultivation are that plants develop more quickly and require less space because they don’t need to spend as much time growing roots to access nutrients. Furthermore, hydroponics enables more effective nutrient/fertilizer management. Aquaponics, a multitrophic system that combines hydroponics and aquaculture, can result in a more efficient use of resources. In other words, plants are grown in nutrient-rich fish tank water. The utilization of fish in rice paddies or irrigation with water from fish tanks, both of which are rich in nutrients, served as models for this approach. Also, future consumption rates must be reduced globally due to diet and food waste. A large quantity of food waste goes to waste around the world including large amounts of nutrients, micronutrients, and minerals. To ensure the sustainable availability and security of food in the future, steps must be taken such as preventing the marketing of surplus crops, enhancing storage, cooling systems, and transportation infrastructure, especially in developing countries, extending the shelf life of perishable goods, educating consumers, and creating practical purchase strategies [1, 2, 6].

8 Conclusion

Managing fluctuations in water resources and external norms on water quality will be a huge problem for humanity in the twenty-first century as food and energy demand continue to rise. A significant amount of additional water will be needed to support future food and energy production, so it is urgent to link sustainable food, energy, and water nexus solutions with practical outcomes and to engage in research that collaborates with regional experts and stakeholders. Additionally, more emphasis must be placed on nutrition rather than just food to examine the nutritional implications of various climate and management scenarios. The triangle of water, food and energy on the globe needed to be manage carefully to meet the energy demands and food hunger in the future. Any technology and process meeting all the three demands will ensure a sustainable future and global management of food and energy shortage.