Water, energy, and food and are strongly interconnected, and the sustainability of the whole world depends on this link. The aim of this article is to analyze the volatility spillovers between indexes representing the financial component of this nexus. We use a multivariate Generalized Autoregressive Conditional Heteroskedasticity (GARCH) model with daily data in which the water variable is proxy by equity index that represents the performance of the industry involved in water business both at the global and local levels. For the food and energy sectors, we use two sub-indexes of the S&amp:P Goldman Sachs (GS)-Commodity Index. Our results highlight the existence of a financial nexus between water, energy, and food that was particularly exacerbated during 2008 crisis. Evidence therefore suggests the need to better investigate the policy options that can be used to reduce price volatility in a framework of the rising relevance of sustainability issues.

Water, energy, and food and are strongly interconnected, and the sustainability of the whole world depends on this link. The aim of this article is to analyze the volatility spillovers between indexes representing the financial component of this nexus. We use a multivariate Generalized Autoregressive Conditional Heteroskedasticity (GARCH) model with daily data in which the water variable is proxy by equity index that represents the performance of the industry involved in water business both at the global and local levels. For the food and energy sectors, we use two sub-indexes of the S&P Goldman Sachs (GS)-Commodity Index. Our results highlight the existence of a financial nexus between water, energy, and food that was particularly exacerbated during 2008 crisis. Evidence therefore suggests the need to better investigate the policy options that can be used to reduce price volatility in a framework of the rising relevance of sustainability issues.

Population growth, increasing demands for food, ever-growing competition for water, reduced supply reliability, climate change and climate uncertainty and droughts, decline in critical ecosystems services, competition for land use, changing regulatory environments, and less participatory water resources governance are contributing to increasing difficulties and challenges in water resource management for agriculture and food. The need for sustainable food security for our global population and the need for preserving the environment, namely natural and man-made ecosystems and landscapes, have created an increased need for integrated, participative and scalable solutions focusing the various levels of irrigation and nature water management, from the field crop to the catchment and basin scales. Meanwhile, challenges and issues relative to water management for agriculture and food have evolved enormously in the last 30 years and the role of active management of the components of the water cycle is assuming an increased importance since their dynamics are key to assure water use sustainability, mainly agriculture and natural ecosystems sustainability. However, different regions face context-specific challenges associated with water scarcity, climate, governance, and population requirements. The main and first challenge is producing enough food for a growing population, which is intimately related with challenges placed to agricultural water management, mainly irrigation management. This paper revises challenges and progress achieved in the last 30 years focusing on irrigated agriculture, mainly water management, and its contribution to food security and the welfare of rural communities.

Analysis the water–food–energy nexus is the first step to assess the decision maker in developing and evaluating national strategies that take into account the nexus. The main objective of the current research is providing a method for the decision makers to analysis the water–food–energy nexus of the crop production system at the national level and carrying out a quantitative assessment of it. Through the proposed method, indicators considering the water and energy consumption, mass productivity, and economic productivity were suggested. Based on these indicators a water–food–energy nexus index (WFENI) was performed. The study showed that the calculated WFENI of the Egyptian summer crops have scores that range from 0.21 to 0.79. Comparing to onion (the highest scoring WFENI,i.e., the best score), rice has the lowest WFENI among the summer food crops. Analysis of the water–food–energy nexus of forty-two Egyptian crops in year 2010 was caried out (energy consumed for irrigation represent 7.4% of the total energy footprint). WFENI can be applied to developed strategies for the optimal cropping pattern that minimizing the water and energy consumption and maximizing their productivity. It can be applied as a holistic tool to evaluate the progress in the water and agricultural national strategies. Moreover, WFENI could be applied yearly to evaluate the performance of the water-food-energy nexus managmant.

We present a network model of interstate food trade and report comprehensive estimates of embodied irrigation energy and greenhouse gas (GHG) emissions in virtual water trade for the United States (U.S.). We consider trade of 29 food commodities including 14 grains and livestock products between 51 states. A total of 643 million tons of food with a corresponding 322 billion m³ of virtual water, 584 billion MJ of embodied irrigation energy, and 42 billion kg CO₂-equivalent GHG emissions were traded across the U.S. in 2012. The estimated embodied GHG emissions in irrigation water are similar to CO₂ emissions from the U.S. cement industry, highlighting the importance of reducing environmental impacts of irrigation. While animal-based commodities represented 12% of food trade, they accounted for 38% of the embodied energy and GHG emissions from virtual irrigation water transfers due to the high irrigation embodied energy and emissions intensity of animal-based products. From a network perspective, the food trade network is a robust, well-connected network with the majority of states participating in food trade. When the magnitude of embodied energy and GHG emissions associated with virtual water are considered, a few key states emerge controlling high throughput in the network.

Tajikistan’s agricultural sector suffers from a highly inefficient use of water and energy resources. As a country that is heavily dependent on energy-intensive pumping irrigation, wastage of water and electricity has severe impact on the country’s energy and food security. The recent opening of potential energy exports further highlights these practises. Water User Associations (WUAs) can mitigate the delicate balance between water, energy and food in Tajikistan. Although they are often still underdeveloped, WUAs can address challenges that hinder agricultural energy efficiency. This paper suggests some low and no-cost technical and policy solutions.

Recent years have shown increased awareness that the use of the basic resources water, food, and energy are highly interconnected (referred to as a ‘nexus’). Spatial scales play a major role in nexus analyses, and can be related to the physical characteristics and dependencies between nexus resources. In fact, water, food and energy are very different in terms of absolute magnitude of production, as well as in the extent to which they are traded. The differences in trade extent can partly be explained by physical differences: high value, high density, geographically concentrated resources are traded more. We show how input-output dependencies are more relevant at local to national scales, whereas the continental and global scales are important due to physical and virtual trade. We combined various insights into an overview of which spatial scales are most relevant for each nexus resource, based on physical characteristics, input-output dependencies, virtual trade, and potential future changes due to socio-economic trends, climate change impacts and climate change mitigation.

Concerns about the water–energy–food (WEF) nexus have motivated many discussions regarding new approaches for managing water, energy and food resources. Despite the progress in recent years, there remain many challenges in scientific research on the WEF nexus, while implementation as a management tool is just beginning. The scientific challenges are primarily related to data, information and knowledge gaps in our understanding of the WEF inter-linkages. Our ability to untangle the WEF nexus is also limited by the lack of systematic tools that could address all the trade-offs involved in the nexus. Future research needs to strengthen the pool of information. It is also important to develop integrated software platforms and tools for systematic analysis of the WEF nexus. The experience made in integrated water resources management in the hydrological community, especially in the framework of Panta Rhei , is particularly well suited to take a lead in these advances.