Among the studies on LSLAs and land grabbing, an alternative hypothesis has developed: what if the main driver of the contemporary global land rush were the need for water rather than for land? . Dell’Angelo et al. have described a “global water grabbing syndrome” to take into account the increasing dynamics of freshwater appropriation occurring as a result of globalization. A fundamental mechanism of transnational water appropriation is associated with large-scale land investments in agriculture. Studying the issue of land acquisitions through hydrological analytical tools provides insights into contemporary hydropolitical trends. Tools such as water footprints and virtual water transfer applied to the study of transnational land investments show that globalization dynamics strongly affect the water resources of developing countries . Rulli and D’Odorico estimate that LSLAs account for the appropriation of about 0.4 × 1012 m3 . The global assessment of appropriation of water through large-scale acquisition, which was defined as global water grabbing, quantified the amount of water appropriated for crop production from acquired land and evaluated potential effects on food security in the countries affected by these investments . The term “water grabbing” has also been used to identify the direct and immediate physical appropriation and diversion of local water resources. Mehta et al. define water grabbing as “a situation where powerful actors are able to take control of, or reallocate for their own benefits,stackable flower pots water resources already used by local communities or feeding aquatic ecosystems on which their livelihoods are based.” This general definition can be applied to a variety of different socio-environmental and political processes of water appropriation besides LSLAs , for example, mining , water withdrawals for hydro power , and other forms of diversion of water for industrial uses.

Several negative social and environmental consequences of water grabbing dynamics have been discussed in the literature. Environmental problems associated with water grabbing range from biodiversity loss, as in hydro power development in the Mekong River basin , to issues of direct contamination of drinkable water as a result of intensive agriculture in Kenya . From a social perspective, issues such as loss of agricultural self-subsistence capacity, dispossession, marginalization of indigenous communities, forced migrations, impoverishment, and disappearance of cultural practices have also been investigated . Other studies specifically address the direct impacts of water grabbing on problems associated with increasing water competition, reduction of water availability, and increased limitations to water access in rural communities . Nevertheless, these affected users and groups are not passive; in many instances they are capable of collective re-action and self-organization. Rodríguez-Labajos and Martínez-Alier describing a conceptual map and a synthesis of water conflicts globally, illustrate how in many cases social movements born in con- flictive contexts developed innovative propositions and modalities for alternative water governance principles, values, and approaches.A key issue at the origin of the FEW nexus concept was the need to maintain food, energy, and water security in the face of competition among components of these systems and different global-change pressures . Resilience in the FEW nexus therefore entails the ability of interacting food, energy, and water systems to cope with different pressures in order to maintain food, energy, and water security . This section focuses particularly on the importance of food security. The definition of food security adopted by the FAO specifies that food availability, access, and adequacy requirements need to be met “at all times”: Human beings cannot remain without food or with unsafe/inadequate food even for short periods of time. Although the demand for food products would be expected to be relatively inelastic , the supply undergoes fluctuations as a result of natural and anthropogenic factors.

Food systems need to be resilient to a variety of shocks operating at different scales that could affect either food production or availability, such as extreme weather, pest outbreaks, market crises, failing institutions, and political conflict . These pressures can ricochet through food trade systems, including export restrictions imposed by key producing countries to address concerns over domestic shortfalls in production. Systems of production therefore need to be robust and either recover after these shocks or adapt to them to be able to deliver food in sufficient amounts with nutritionally adequate quality and affordable prices . The study of the resilience of food systems should involve the environmental, institutional, economic, and political dimensions of food security and examine how they can affect agricultural production, food trade, and price dynamics to determine the availability, accessibility, and adequacy requirements of food security . Such an approach has been attempted by some partial equilibrium trade models developed to support policymakers in reducing poverty and hunger . Other models have been developed to investigate the short-term response to shocks . These models do not invoke equilibrium conditions, which could be hard to attain in the short-term response to an abrupt production shock. Rather, they rely on a simple set of rules to show the spread of a perturbation through the global system of production and trade . Other approaches invoke the general resilience theory to evaluate the effect of a variety of factors that are known to affect resilience in socio-environmental systems, such as reserves or other types of redundancy, diversity , variability, openness, connectivity, and modularity in trade networks, social capital , and adaptive governance. To date, only some of these factors have been investigated in the context of food security because the multi-scale nature of the problem and difficulty in quantifying some aspects of the food system present a tremendous challenge.A classic example of redundancy is the existence of an excess of production in various regions around the world. In case of shock, it is possible to meet the local demand by importing food from those regions.

The intensification of trade and the consequent increase in trade dependency on a regular basis has reduced redundancies, thereby eroding societal resilience . Thus, in an interconnected world, the dependence on international trade has increased while the resilience of the food system has decreased to the point that local deficits in crop production have led to global food crises. Global food crises were observed in 2008 and 2011 for the first time after decades of abundance. In those years, crop failure induced by extreme environmental conditions in major food producing regions of the world led to an increase in crop prices , an effect likely amplified by human factors, such as commodity speculation and fear.To contain such a price escalation, some major exporting countries issued export bans that left import-dependent countries in a state of food insecurity . Thus, the globalization of food through trade and the consequent intensification of trade dependency may reduce the resilience of the food system because markets could fail for economic and political reasons.In the longer run other redundancy factors could contribute to resilience. For instance, the presence of untapped resources, such as land and freshwater,flower pots for sale would allow for an increase in crop production during aperiod of prolonged crisis, assuming that the institutions are well equipped to facilitate adaptation in the agricultural sector. Thus, the presence of under performing agricultural land with relatively big yield gaps, the availability of unutilized freshwater resources to close those gaps, and the possibility of sustainably expanding the cultivated land are all examples of biophysical redundancies that could be used in the midterm response to shocks in the food system. In other words, biophysical redundancy accounts for unused biotic and abiotic environmental resources and represents a form of “stand-by redundancy,” whereby some spare resources are idle and will be taken into the production in case of failure in other parts of the food system. It has been estimated that the biophysical redundancy of 102 out of the 155 countries included in a recent study has decreased in the last two decades. In 75 of these countries, the biophysical redundancy is not sufficient to feed 50% of their population that, collectively, accounts for 4.8 billion people . The notion of biophysical redundancy has some clear limitations because some of the idle or unused resources play an important environmental role for the provision of habitat for pollinators and other species, water purification, and other ecosystem services that are crucial to agriculture and human well being. As noted in section 11, agricultural expansion often comes at huge environmental cost in terms of land use change, habitat loss, carbon emissions, and species extinction. Thus, yield gap closure appears to be a better response to shocks in the system than agricultural expansion. However, both putting additional land under the plow and closing the yield gap are measures that can occur only in the middle to long term and are not quick responses to crises; both measures require capital, technology, and knowledge that are not equally distributed among countries.The most obvious form of redundancy is represented by food stocks, which have been used to mitigate the effect of crop failure and famine since biblical times. These reserves are accumulated in years of plenty and used in years of scarcity, thereby making the food system more resilient . Despite this very intuitive understanding of the dynamics of food stocks and of the role they play in the national and global food security, these reserves can be difficult to manage because of technical problems related to storage and preservation and because of their effects on supplies and prices . Food stocks can be established at the farm, national, or regional scale and managed with different goals, including food security , price stabilization , food aid, and financial speculations .

Recent studies have shown that over the last few decades regional and global per capita food reserves have remained stationary, despite a widespread concern that food stocks might be shrinking . However, it has been estimated that the global per capita stocks could be halved by 2050 . There are some interesting regional differences: while Western Europe, North Africa, and the Middle East keep smaller and less volatile per capita food stocks, North America and Oceania have bigger and more volatile per capita stocks. In sub-Saharan Africa per capita food reserves are smaller and more volatile , which indicates an overall higher food insecurity .Studies on famines and deprivation have highlighted that, during many food crises, the problem has been the lack of access to food rather than lack of food . Loss of economic access is often induced by spikes in food prices that prevent the poor from having sufficient financial resource to buy food. Because more wealthy segments of the population are in a better position to buy food, wealth can give a household or a country the ability to cope better with food crises. In other words, the wealth of individuals or of entire countries may be used as an indicator of economic resilience. To this end, Seekell et al. Suggest using a country-specific indicator defined as the ratio between the income of the lowest quintile of the population and food cost in same country. This ratio is not constant because affluent societies are known to spend only a small fraction of their income on food .The resilience of the food system is affected by the globalization of food through trade . The effect of import dependency and inter connectedness of the food system is difficult to evaluate because we are dealing with a complex system that is undergoing transient growth and is prone to shocks from environmental and socioeconomic drivers. A quantitative approach to investigate the long-term ability of the system to recover from shocks or perturbations is based on the theory of dynamical systems, Lyapunov stability, and exponents . In this framework, the dynamics are expressed through a set of coupled differential equations that can be linearized typically around either a steady state or a dynamic equilibrium. The linear stability analysis is typically used to determine whether the perturbation is in the long run amplified or damped, in other words, whether the system is stable and to what extent in the long run it is able to recover from perturbations . This approach was adopted by Suweis et al. , who studied the stability of the coupled global food–population dynamics within a network whose nodes and links represent the countries of the world connected by trade. At each node, the population dynamics are expressed by a demographic logistic model with carrying capacity that depends both on domestic food production and trade patterns .