James S. Clark, Dave Bell, Michael Dietze, Michelle Hersh, Ines Ibanez, Shannon LaDeau, Sean McMahon, Jessica Metcalf, Emily Moran, Luke Pangle, and Mike Wolosin
This article focuses on the use of Bayesian methods in assessing the probability of rare climate events, and more specifically the potential collapse of the meridional overturning circulation (MOC) in the Atlantic Ocean. It first provides an overview of climate models and their use to perform climate simulations, drawing attention to uncertainty in climate simulators and the role of data in climate prediction, before describing an experiment that simulates the evolution of the MOC through the twenty-first century. MOC collapse is predicted by the GENIE-1 (Grid Enabled Integrated Earth system model) for some values of the model inputs, and Bayesian emulation is used for collapse probability analysis. Data comprising a sparse time series of five measurements of the MOC from 1957 to 2004 are analysed. The results demonstrate the utility of Bayesian analysis in dealing with uncertainty in complex models, and in particular in quantifying the risk of extreme outcomes.
Nourishing food and water are essential for human survival, as are the people who labour in the food system and the planetary ecosystems that underpin foraging, farming, and fishing. Our countries share one planet, woven together by inextricably linked natural and social systems. Global demand for food and water is increasing, while ecosystem decline, poverty, food insecurity, sociopolitical injustice, and racial inequities persist. Meeting food needs exerts tremendous pressure on planetary systems, yet fragmented social, political, economic, and environmental policies continue to threaten food system integrity and sustainability. Global food systems that reflect dietary patterns designed to promote food and water equity while respecting planetary limits, will require embracing values-informed, place-based policies and practices. Food system transformation represents an underutilized but very tangible avenue through which human and planetary well-being can be simultaneously reenvisioned and redirected toward a more health promoting, sustainable, equitable, and resilient future.
Alternative food movements have, from their origins, espoused values of social justice and environmental stewardship in an attempt to challenge existing economic and social norms related to food and farming. Three alternative food movements in North America exemplify the trade-offs between the three pillars of sustainable development: social equity, environment, and economy. Organic food has brought environmental benefits, but has struggled to challenge the status quo and promote the social benefits of the original movement when it goes to scale. Farmers’ markets have brought social and environmental benefits, but only in some cases reduced costs when compared to mainstream market levels. Consequently, good-quality food is often out of reach of low-income groups, as highlighted in a case study of access by underserved people in British Columbia, Canada. Regional food movements are a hybrid approach that balance some of the gains and some of the challenges of these systems. The extraordinary concentration of power in North American food systems stands in contrast to notions of social equity and undermines efforts to effect change in pursuit of sustainable alternative food systems.
Anthony J. Reynolds
Conservation agricultural practices have been widely adopted across the world in the past 30 years. Farmers recognized that their soils had been degraded by deep ploughing and by dependence on chemical fertilizers, pesticides, and herbicides. Conservation agriculture, involving the agronomic and technological practices of no-till, cover cropping, and rotation, can be a sustainable alternative to conventional farming both economically and environmentally. While improving soil and crop health, it also has a dramatic and beneficial impact on the soil structure and on organic matter content that in turn can improve drainage and the availability of water. Costs are greatly reduced and crop yields—after an initial decline—return to former levels. Increasing interest and uptake by the global farming community shows that the system can be adapted in a variety of farming situations and significantly aid both the environment and sustainable food production.
Rami Zurayk and Azza Dirar
Since agriculture consumes the largest share of the world’s water, farmers undoubtedly play an instrumental role in the management of this precious resource. As such, various policy approaches have sought to engage farmers in the management of water for irrigation. There is much literature on policy approaches that devolve irrigation management to farmers through organizing them into ‘water user associations’ and mobilizing them into cooperative water resource management. When the implementation experience and success of these approaches are assessed, the results show a great variation in experience with overall limited success. The key challenges stem from various assumptions underlying the policy approaches, namely the way in which farmers are conceptualized as a homogenous group of ‘water users’. Cooperative and participatory approaches to natural resource management cannot be institutionally manufactured without addressing key political ecological realities and the wider contexts in which ‘resource users’ operate.
Mustapha Besbes, Jamel Chahed, and Abdelkader Hamdane
Northwest African countries (NA) consume 70 percent of their renewable water resources, and groundwater overdraft has become a major problem. Blue water irrigation represents 17 percent of overall water resources and is economically significant. Green water represents 83 percent, but is not yet well evaluated, and is not considered in national water strategies, along with virtual water embedded in international food trade. Irrigation enhances local agrifood production but it has not changed the proportion of staple foods. The region remains a major net food importer and, largely due to population increase, water dependency increased from 30 percent to 50 percent between 1970 and 2010. Population forecasts predict that water demand will continue to grow, and could reach more than three times the present level. Given the blue water status, NA must develop approaches to cope with water–food challenges, based on international virtual water flow optimization and better green water valorization.
Peter Johnston and Arthur Chapman
Irrigation is a critical input for raising food production in southern Africa, parts of which are food-insecure, especially as a result of low levels of technology employed, low investments into the sector, small farm sizes, and high levels of exposure to the hazards of climate variability. Most food production (including exports) and irrigation in the region occurs in the arid south—in South Africa by a large margin. Further north, in Angola, Zambia, and the northern parts of Mozambique, water resources are abundant yet irrigation farming is far less developed and inefficient, resulting in water resources being less intensely managed. The region needs to become more tightly integrated economically, with a greater flow of technology, investment, and management capability to the north, allowing the north to produce more food (and other agricultural products) which would flow to the more industrialized south—essentially virtual water flows to that region.
America Lutz Ley, Ryan Lee, Yulia Peralta, and Christopher Scott
The United-States-Mexico food system, and in particular the section located in the Sonoran Desert, is an example of the detrimental effects that result from instensified food production to supply increased demand from regional, transboundary, and global areas. Impacts to freshwater and terrestrial ecosystems in addition to human livelihoods and institutions create serious management and policy challenges. Understanding the region as an integrated water-food system with institutional imbalances reveals the following consequences: (a) an increasing reliance on groundwater resources for the majority of agriculture and livestock production; (b) a net export of nonrenewable water; and (c) a virtual water imbalance that further threatens the region’s water and food security.
Michel Petit and Phillipe Le Grusse
The food and water challenges to be faced in the Mediterranean Basin, particularly those on the southern and eastern shores, are daunting. They form a complex nexus of problems and require policies pursuing several important potentially conflicting goals at the same time: reducing or limiting food import dependency through increased agricultural production in environmentally sustainable ways while protecting the natural resource base and keeping food affordable for poorer populations. The worrisome trends affecting countries on the southern and eastern shores of the common sea can also have seriously negative consequences in the North which explains why the North-South collaboration has a long tradition in the region. But, as the case of water management institutions shows, ineffective advocacy for trade liberalization has led to conflicts and tensions on various issues and has distracted attention from potentially much more fruitful areas of collaboration.
West Asia is one of the most water-scarce regions of the world and one of its foremost importers of virtual water despite sustained efforts at self-sufficiency, especially in cereal production. Technology-oriented policy solutions eye a reorientation of agriculture towards fruit and vegetables that are less water-intensive than cereals and provide more value added per water unit consumed. Turkey is a role model here; the country has an agricultural trade surplus and ranks among the top ten agricultural economies globally in value terms. Yet technology-oriented policy prescriptions overlook the sociopolitical ‘problemsheds’ that emerge (along with new agro-lobbies) and agriculture as the main water consumer has to compete with other economic sectors and sprawling urbanization. This article looks at the different categories of countries and their specific challenges.
Brendan Bromwich, Tony Allan, Anthony Colman, and Martin Keulertz
Society’s greatest use of water is in food production, a fact that puts farmers centre stage in global environmental management. Management of food value chains, however, is not well set up to enable farmers to undertake their dual role of feeding a growing population and stewarding natural resources. This chapter introduces an analytical framework by which food, water, and society can be investigated. Food value chains comprise three market modes: production; trade and process; retail and consumption. The model demonstrates the interfaces between blue water, green water, virtual water, polluted drainage, and evapotranspiration. By categorizing social, cultural, and political influences on the three market modes the framework enables integrated analysis of food, water, and society . The combined management of food and water through redesign of food value chains emerges as a key challenge for the twenty-first century.
Phil Riddell and Biksham Gujja
This chapter considers the challenges and opportunities with respect to meeting the demand for rice in the context of a trade-based concept of water, food, and nutrition security. It notes that there is more to rice than just its food value. It also has cultural values and various industrial uses while certain rice schemes have environmental or flood management benefits. The structure of the global rice sector is then presented in terms of production, demand, and trade which serve to confirm the importance of rice as an agricultural commodity. However, current production practices are—in many locations—characterized by challenges in terms of productivity, climate change, genetics, political economy, and cartels. These are analyzed before the text focusses on measures to increase the water productivity of rice before providing a ‘horizon view’ of supply and demand, prices, and the need for expanded production or new producing areas.
Floriane Clement and Alan Nicol
Whereas international debates have increasingly acknowledged the role of gender in food and water security, they have often focussed somewhat exclusively on the role of women in agricultural production. This chapter aims at broadening our understanding of gendered inequities in food and water systems by examining how power structures produce gender-differentiated capabilities along the real-virtual water spectrum. The analysis reveals how gender, intersecting with class, ethnicity, and other social categories, shapes the capabilities to engage in, benefit from, and influence food and water systems. The findings show the relevance of using a commodity chain analysis to highlight the linkages between, for example, food standards in the Global North and gendered exploitative work conditions in the food export industry in the Global South. To conclude, this chapter calls for deliberative approaches to develop just food and water systems by considering the values, preferences, and trade-offs of diverse social groups engaged in these systems.
Given that food production requires a lot of water, more than any other economic sector, one would expect that the world’s food production concentrates in places where water is relatively abundant. This chapter, however, highlights the paradox that various water-poor countries produce food for export to water-rich countries. Food commodity prices do not reflect the cost of water inputs or of damaged water ecosystems, so that the global food market lacks economic incentives to source from places with less harmful impacts on local water systems. The costs of ‘traded’ embedded water thus remain invisible. The chapter proposes an international water label for water-intensive products and argues that international trade rules should include regulations on sustainable water use.
Amir Kassam and David Coates
Conventional tillage agriculture has a built-in propensity for soil erosion and land degradation leading to loss of ecosystem services that are required to sustain agricultural production as well as minimize off-farm impacts. It is associated with suboptimal crop and land productivity. The global uptake of Conservation Agriculture (CA), which is a recognized flagship alternative crop production approach, is built upon three practical interlinked principles of: no or minimum mechanical soil disturbance (‘no-till’), soil cover management, and diversified cropping. The current spread of CA globally is 180 M ha of annual cropland (12.5 per cent), increasing annually at 10 M ha. Knowledge of how CA positively affects ecosystem services at the field and landscape level, with emphasis on water-related services and food security, shows that CA has the potential to meet, or exceed, most of the current shortfall in projected global agricultural water demand by 2050.
The globalization of agrifoods systems is transforming the value chain of multiple food commodities, including wheat. Demand for grains will continue to rise amidst challenges such as water stress and price volatilities. The wheat global value chain is complex and depends on a handful of exporters and international trading houses. International lead firms in the chain are the primary buyers and they link production to consumption regions. Their role has implications for food security and grain trade. This chapter uses the global value chain (GVC) lens to examine the global wheat industry, its governance structure, and the key value chain dynamics that drive power in the chain. GVCs refer to the sequence of value-added activities that comprise the creation, delivery, and end use of a given product or service and the role of actors in the chain.
Green water is defined as the water in soil that is potentially available to plants for uptake and subsequent transpiration. Despite the fact that crop biomass is directly related to transpiration and the global transpiration flow alone matches that of all the rivers in the world, green water has until recently been largely neglected in research on food security. That long neglect is redressed by a review of recent research on the role of green water in the production of agricultural commodities to meet current and future world food demand, including how the differences in water requirement between plant-based and animal-based commodities play out in respect to the food-water nexus. Informed by current literature, a case is made for optimizing green water management to achieve a global increase in food production from 20 to 40 percent without an expansion of either agricultural land use or the volume of water withdrawn for irrigation.
David Leslie Dent
All fresh water is delivered by the soil. There are two critical junctures: when rain hits the ground—where it may infiltrate or run off carrying the soil with it; and in the soil itself—where it may evaporate from a bare surface, be taken up by roots, or drain to streams and groundwater. Both partitions are managed by farmers so every land-use decision is a water-use decision. Green water is held in the soil and used by plants—the more green water, the more primary production; and the best soils supply orders of magnitude more than the poorest. Practices that maximize the green water resource, such as conservation agriculture, arrest soil erosion, maximize soil water storage and groundwater recharge, and moderate floods. But water consumed in the fields where it falls is not available for use elsewhere.
Julie Rozenberg, Laura Bonzanigo, and Claire Nicolas
Increasing the amount of resilient infrastructure investments in developing countries is key to achieving development goals. Two issues need to be addressed to better support investment decisions. First, analysts need to better integrate the social, economic, and environmental dimensions of investment decisions in their quantitative analyses, given the intertwined objectives of climate change adaptation and poverty reduction. Second, analysts and practitioners need to recognize that the future state of those three dimensions is deeply uncertain and that new techniques need to be used that look for robust investments—performing well under multiple future conditions—rather than an optimal solution under a single prediction of the future. Doing so can be achieved by beginning important decision processes with an integrated model representing technical and socioeconomic factors, and exploring various interventions under many possible futures.
Incentive Programs to Address the Challenges of Hunger, Undernutrition, and Obesity in the United States
Gus Schumacher and Emily Nink
Across the world, many people remain food insecure, and unhealthy dietary patterns are driving up health costs. Solutions to these problems will impact food production and water scarcity. This chapter reviews the history of government interventions to improve food security and nutrition in the United States, which have enjoyed a “broad coalition” of support over seven decades. More recently, nutrition incentive programs have emerged, aiming to increase purchases and consumption of fresh fruits and vegetables by low-income consumers who benefit from the federal nutrition programs. This chapter explores the development and programmatic success of nutrition incentives, impacts on consumers’ food security and nutrition, impacts on farmers and farmers’ markets, and potential contributions to shifting dietary patterns. As they mature, evolve, and scale, nutrition interventions may deliver shorter supply chains, increase fruit and vegetable consumption, and contribute to a shift toward more sustainable and nutritious foods.