The term ‘Water, Energy and Food Nexus’ (WEF Nexus) is quite popular in contemporary environmental debates and scientific discussions. This contribution aims at outlining the contents of the WEF Nexus as a new integrated management paradigm. It presents a review of key recent publications on the topic in order to provide insights on four issues: the drivers behind the WEF Nexus, its precursors in sustainability science and integrated management, the different understandings of ‘integration’ under the Nexus and the perception of the usefulness in academic literature. Some preliminary results of this literature review can be highlighted in this place. Three lines of justification for the need of the WEF Nexus debate exist in respective literature. Increasing resource interlinks due to growing scarcities represent the empirical or analytical, often-cited argument for the Nexus. Further, recent resource crises are strong reminders for the need for cross-sectoral debates. Further, the failures of sector-driven management strategies constitute another driver for the emergence of the Nexus debate.
As an integrated management paradigm, WEF Nexus as an integrated management paradigm highlights the three aspects of a) intersectorality of resource use issues, b) interdependence and interdisciplinarity of management decisions and c) interactionality of impacts of resources allocations. In doing so, it builds on arguments from precursor concepts especially in the 1990s. Yet, the Nexus integrative approach stresses all three mentioned aspects while previous integrated management approaches were sector-focused framings and understood integration mainly in regard to subsectors and disciplines.
Nexus has evolved as an important integrated management paradigm, although there is no uniform way to understand integration under the Nexus. This paper examined 32 key Nexus literature to categorize views on two key questions: How should the ‘process of integration’ look like, i.e. which links should be examined and at which stage of the management value chain?; and, second, how should the ‘state or view of integration’ look like, i.e. in which institutions and by which actors? As a result, the paper presents three key understandings of issue integration under the Nexus: integration as incorporation, integration as cross-linking and integration as assimilation.
Finally, this paper evaluates the perception of scientists on the usefulness of the Nexus according to different categories. The overall conclusion of this evaluation is that WEF Nexus has been able to change current policy debates. At the same time, scientists hold different views on the essence of the novelty of the WEF Nexus and criticize the absence of a clear implementation roadmap or recommendations on institutional and participatory arrangements to integrate WEF Nexus into current environmental governance frameworks.
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The role of agricultural sector is vital for socio-economic well-being, especially in the Mediterranean area, which provides food products for the whole Europe. However, the increasing food demand in the last decades, due to population growth and economic development, originates an increasing pressure on water resources, with cascading effects on energy consumption. In fact, both water availability and energy accessibility are intertwined and influential on agricultural production. The starting issue related to water management at local scale, is the unsustainable water withdrawal, which, in agricultural activities, is typically associated to an excessive energy consumption. Usually, this may depend on both water and energy inefficiencies (physical as well as managerial), having cascading impacts in terms of costs for the farmers and their behaviour. Developing effective and sustainable water resources management policies is essential at local scale and should be based on the conceptual framework of the Water-Energy-Food Nexus (WEFN). WEFN approach requires, at local level, a deep knowledge of the involved phenomena and supports to identify and model the main dynamics, even the hidden effects.
The aim of this research activity is to evaluate the impacts of different dynamic phenomena such as crop, market conditions and water availability/accessibility, both on water and energy consumption at local scale. The case study is Capitanata (North Apulia region), a semi-arid area affected by significant problems of water scarcity, characterized by a high agricultural vocation and by intensive crops cultivations. It is one of the richest agricultural districts in Italy, with a total area of 455,000 ha. A consortium manages approximately 150,000 ha, but about 126,000 ha are currently served. A conceptual model is being developed, in order to analyze different dimensions of the water–energy-food nexus (WEFN). Water Footprint (WF) is assumed as an indicator of water consumption. The model is constituted by three main sub-models related to “food”, “water”, “energy”, strictly connected each other and aims to evaluate the water and energy consumption associated to industrial tomatoes production in the period between 2000 and 2011. It will allow, also to evaluate the socio-economic effects in a perspective of water and energy consumption reduction through a system dynamic modelling techniques.
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During the past years, as interdependencies and complex feedbacks among different resources have become increasingly apparent, the ‘nexus’ around conflicting needs that challenge food, energy and water (FEW) security entered public, private and political agendas. Despite of the objective to establish nexus-enabled policy-making to support the transition to sustainable development by reducing trade-offs and externalities among the nexus sectors, it has become apparent that currently societies are only vaguely organized as to effectively implement integrated, trans-sectoral planning and action. Precondition for the required transition is a comprehensive understanding of the feedbacks and interlinkages between the provision of water, energy and food. A review of available nexus publications by both international organizations and the scientific community, however, has revealed that so far neither a consistent definition nor a common conceptualization exists that can serve as a fundament for structuring a systematic analysis of the many facets of nexus challenges necessary to develop well-informed governance strategies.
Objective of the first research phase was therefore the development of a systematic understanding of the multiple scales, perspectives and surrounding conditions that frame the “FEW nexus security challenge”. The derived framework is multi-dimensional and integrates the FEW nexus across the three levels of (a) natural system boundaries, (b) socio-economic system boundaries, and (c) political system boundaries. On the socio-economic level, FEW nexus security implies that food, energy, and water security are evenhandedly pursued with the objective to ‘provide all people, at all times, not only adequate physical but also economic access’ to these resources. This, however, implies accounting for not only regional specificities but also trans-national or even global effects. The socio-economic sub-system thus in itself constitutes a complex system that methodically requires a multi-objective optimization. Further complexity emerges from the multiple scale gaps inherent in FEW nexus management: Natural resources – including water, (arable) land or fossil resources – are limited and geographically unevenly distributed (i.e., the natural system boundaries). At the same time both the demand intensities as well as the (negative) externalities related to the growing demand for these resources are globally also unevenly allocated and inequitably distributed (i.e., the socio-economic system boundaries). Yet, governance strategies for the management of these resources are often developed based on national (political) rather than geographical system boundaries (i.e., the political system boundaries).
In order to operationalize an integrated assessment of these multi-dimensional challenges, the developed conceptualization is translated into a modular, stakeholder-based modelling framework which describes a model-based definition of FEW nexus security. Following the UNEP procedure for indicator identification , for each module the following issues will be addressed in a systematic stakeholder process: (a) identification of potential issues and concerns, (b) assessment of each issue and how it relates to the natural environment, (c) analysis of underlying causes and interlinkages, and (d) analysis of impacts on society, economy and environment. The final step of each module-specific stakeholder process consists in determining the adequate methodical tools for assessment based on the identified indicators, as well as their requirements for integration into the comprehensive integrated assessment framework.
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Understanding the Water-Energy-Food nexus calls for integrated modeling, while at the same time posing particular challenges. The very concept of the nexus has garnered attention because of unintended consequences that have arisen when efforts to provide water, energy, or food have ignored the deep interconnections of these systems. Addressing the nexus requires that our models need to expand their boundaries and introduce new linkages between systems. The challenges to doing so are significant, however. These relate to a lack of understanding of the interconnections, which is closely connected to a lack of data on many key aspects of the water, energy, and food systems. Furthermore, the addition of more interconnections can make models more difficult to understand and to explain. Thus, we need to be innovative in our efforts to enhance our models, but also modest in our expectations as to what we can expect to achieve.
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The human water demand for agriculture, industry, energy and domestic is less than ten per cent of the global freshwater production of around 54,000 km3 per year. Water is distributed unequally in time and space. Not a new insight, but when we zoom in and look at country and regional level and monthly time scale the global picture is dispatching into areas and periods of water abundance and water scarcity, which we can quantify.
This study uses the multi-model approach of the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP) to build up a consistent set of global water scenarios based on Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs) for the IIASA Water Futures and Solutions Initiative (WFaS). The WFaS “fast-track” assessment applies three water scenarios based on feasible combinations of two different RCPs and three SSPs, then five different hydrological models are used to estimate water availability and three water use models to estimate water demand from different sectors. Results are shown as indicators for e.g. water stress and water dependency between countries for present time and for future projections up to 2050. The alterations to previous studies are the multi-model approach and the finer temporal monthly scale, showing the temporal and spatial diversity of water demand and availability.
One example scenario is based on the combination of SSP2 and RCP6.0. While in 2010 17 countries out of 249 facing severe water stress on an annual basis, the number is likely to increase up to 26 countries by 2050. Looking at the monthly time dimension 51 countries with altogether 3.8 billion people are under severe water stress in at least one month in 2010. This will rise up to 57 countries and 4.9 billion people by 2050. Main driver of this development will be the rising water demand of a growing population and to a lesser extend the changing distribution of water availability. Model biases are inevitable in meteorology and hydrology, therefore we use a multi-model approach for greater confidence in model results and to estimate uncertainties due to scenario and model bias. This study also shows the variability across the scenarios and models.
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