Green roofs are strategic tools that can play a significant role in the creation of sustainable and resilient cities. They have been largely investigated thanks to their high retention capacity, which can be a valid support to mitigate the pluvial flood risk and to increase the building thermal insulation, ensuring energy saving. Moreover, green roofs contribute to restoring vegetation in the urban environment, increasing the biodiversity and adding aesthetic value to the city. The new generation of multilayer green roofs present an additional layer with respect to traditional ones, which allows rainwater to be stored, which, if properly treated, can be reused for different purposes. This paper offers a review of benefits and limitations of green roofs, with a focus on multilayer ones, within a Water-Energy-Food-Ecosystem nexus context. This approach enables the potential impact of green roofs on the different sectors to be highlighted, investigating also the interactions and interconnections among the fields. Moreover, the Water-Energy-Food-Ecosystem nexus approach highlights how the installation of traditional and multilayer green roofs in urban areas contributes to the Development Goals defined by the 2030 Sustainable Agenda.

Extant studies address water, food, and health security issues considerably separately and within narrow disciplinary confines. This study investigates the links among these three issues from an ecological viewpoint with a multidisciplinary approach in a modified Millennium Ecosystem Assessment framework developed by the United Nations. The modified framework includes water, food, and health security considerations as the three constituents of human well-being from an ecological (more specifically, ecosystem services) viewpoint. This study examines the links through published data associated with the Minamata incident, which was a historic and horrific methylmercury-induced water, food, and health poisoning crisis in Japan. The results show that when heavy metal pollution changes one component (marine water) of the provisioning ecosystem services, this change subsequently affects another component (seafood) of the services. This then defines the linkages among water, food, and health security as the three constituents of human well-being within the modified framework. The links can have immediate and far-reaching economic, social, legal, ethical, and justice implications within and across generations. This study provides important evidence for emerging economies that ignore the water–food–health security nexus.

Herein, we investigated the relationship between water, food, and energy (W–E–F) in different regions of China to provide suggestions for sustainable and stable regional development of these resources. Based on the system theory, we constructed three relevant subsystems and analyzed the action mechanism between them. Furthermore, we constructed a network based on the super-efficiency data envelopment analysis model for a W–E–F input–output index system. This model was applied to 30 areas in China from the year 2005 to 2015 for measuring W–E–F coupling efficiency. We conducted a spatial correlation analysis to measure the results. This study demonstrated that the overall regional and interprovincial W–E–F coupling efficiency was low, with food subsystem as the main reason for low efficiency in the entire system and key reason for regional differences. When comparing the three subsystems, the efficiency value of the water resources subsystem showed little change over time. In 2015, the water resource efficiency in most regions reached an effective and effective marginal state. The efficiency of the energy subsystem and the food subsystem is on the rise. Overall, the food subsystem's efficiency is low, and in 2015, the food efficiency of several regions in northwest China was between 0.2–0.4 Spatial agglomeration was detected in W–E–F coupling efficiency in various regions of China. From a local spatial differentiation perspective, the proportion of the low–low (LL) space-related agglomeration pattern and high–high (HH) agglomeration was substantial. The LL agglomeration was primarily concentrated in the western and central underdeveloped areas, and a relatively stable space distribution of HH agglomeration occurred mainly in the eastern region.

The water-food nexus in the Middle East and Northern African (MENA) region is characterized by resource depletion, import dependence and environmental degradation. This contribution proposes that consumption awareness and resource circularity can be seen as a pathway to alleviate environmental problems and achieve long-term supply security in the water and food sectors. The chapter introduces wastewater recycling as a salient and highly relevant development in the MENA region. Current directions in using treated wastewater are analyzed. Furthermore, forerunner countries from different MENA sub-regions are briefly introduced with the focus on the particular characteristics and policy challenges in each of presented cases of wastewater reuse. Furthermore, crosscutting issues are presented. These include the need for addressing the large consumption footprints in MENA countries, the existence of distorting subsidies for agricultural water, the lack of communities' participation, the inadequacy of existing strategies and the suboptimal coordination mechanisms between water and food sectors. We suggest at the end of the paper some recommendations to policy makers in the region. | Scopus

Ending hunger and ensuring food security are among targets of 2030 s SDGs. While food trade and the embedded (virtual) water (VW) may improve food availability and accessibility for more people all year round, the sustainability and efficiency of food and VW trade needs to be revisited. In this research, we assess the sustainability and efficiency of food and VW trades under two food security scenarios for Iran, a country suffering from an escalating water crisis. These scenarios are (1) Individual Crop Food Security (ICFS), which restricts calorie fulfillment from individual crops and (2) Crop Category Food Security (CCFS), which promotes eating local by suggesting food substitution within the crop category. To this end, we simulate the water footprint and VW trades of 27 major crops, within 8 crop categories, in 30 provinces of Iran (2005 2015). We investigate the impacts of these two scenarios on (a) provincial food security (FSp) and exports; (b) sustainable and efficient blue water consumption, and (c) blue VW export. We then test the correlation between agro-economic and socio-environmental indicators and provincial food security. Our results show that most provinces were threatened by unsustainable and inefficient blue water consumption for crop production, particularly in the summertime. This water mismanagement results in 14.41 and 8.45 billion m3 y-1 unsustainable and inefficient blue VW exports under ICFS. Eating local improves the FSp value by up to 210% which lessens the unsustainable and inefficient blue VW export from hotspots. As illustrated in the graphical abstract, the FSp value strongly correlates with different agro-economic and socio-environmental indicators, but in different ways. Our findings promote eating local besides improving agro-economic and socio-environmental conditions to take transformative steps toward eradicating food insecurity not only in Iran but also in other countries facing water limitations. © 2021, The Author(s). | We would like to thank the reviewers of the manuscript for their constructive comments. Thanks to Ms. Manuela Rosso—Brugnach for proofreading the article. This Project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Earth@lternatives Project, Grant agreement No 834716). Brugnach is supported by the Spanish Government through María de Maeztu excellence accreditation 2018–2022 (Ref. MDM-2017-0714) of BC3.

Water-Energy-Food (WEF) Nexus and CO2 emissions for a farm in northwest Iran were analyzed to provide data support for decision-makers formulating national strategies in response to climate change. In the analysis, input–output energy in the production of seven crop species (alfalfa, barley, silage corn, potato, rapeseed, sugar beet, and wheat) was determined using six indicators, water, and energy consumption, mass productivity, and economic productivity. WEF Nexus index (WEFNI), calculated based on these indicators, showed the highest (best) value for silage corn and the lowest for potato. Nitrogen fertilizer and diesel fuel with an average of 36.8% and 30.6% of total input energy were the greatest contributors to energy demand. Because of the direct relationship between energy consumption and CO2 emissions, potato cropping, with the highest energy consumption, had the highest CO2 emissions with a value of 5166 kg CO2eq ha−1. A comparison of energy inputs and CO2 emissions revealed a direct relationship between input energy and global warming potential. A 1 MJ increase in input energy increased CO2 emissions by 0.047, 0.049, 0.047, 0.054, 0.046, 0.046, and 0.047 kg ha−1 for alfalfa, barley, silage corn, potato, rapeseed, sugar beet, and wheat, respectively. Optimization assessments to identify the optimal cultivation pattern, with emphasis on maximized WEFNI and minimized CO2 emissions, showed that barley, rapeseed, silage corn, and wheat performed best under the conditions studied. | publishedVersion

The efficacy of electrolyzed water (EW) to inactivate Listeria monocytogenes on stainless steel surfaces was evaluated and modelled in the present study. L. monocytogenes was inoculated on stainless steel coupons and subsequently subjected to Neutral EW (NEW, pH = 7.0) and Slightly Acid EW (SAEW, pH = 5.0) with different Available Chlorine Concentration (ACC, 50–200 mg/L) for different exposure times (0–6 min). The number of viable cells on coupons decreased as the exposure time increased at all ACC concentrations. Treatments with SAEW resulted in higher reductions of L. monocytogenes, i.e., 2.30 ± 0.16 to 5.64 ± 0.11 log cfu/cm², in comparison with NEW treatments (1.55 ± 0.11 to 5.22 ± 0.12 log cfu/cm²), probably due to the synergistic bactericidal effect between the acidic pH, higher oxidation-reduction potential and the effective form of chlorine, reported in previous studies. Since SAEW was the most effective against L. monocytogenes, two approaches were tested to model the survival data: the one- and two-step modelling procedures. The Weibull model was suitable to describe the survival data and both approaches produced suitable survival models (adj-R²>0.92 and MSE<0.2). EW is effective in reducing bacterial contamination on food-contact surfaces and the survival data and models derived from this study are relevant to optimize its use as an environment-friendly sanitizer in the food industry.

Water, food, energy, climate change and land subsystems are closely intertwined, and play remarkable roles in regional resources management system. Quantification of connections, synergies, and tradeoffs across these subsystems is needed in a more integrated and comprehensive manner, which is challenging due to the complexities and uncertainties involved therein. This paper proposed an inexact optimization approach from a novel water-food-energy-climate change-land (WORLD) nexus perspective, which has potential to promote social-economic development, guarantee livelihood security, and achieve low-carbon target. The approach is capable of (1) helping decision makers identify optimal policy alternatives among water, land, and energy, balancing economic benefit, water supply guarantee rate, hydroelectric generation, water-land utilization, crop yield, and greenhouse gas emission, via a multi-objective non-linear optimization model; (2) providing decision makers insights into in-depth analysis of optimal water-land resources allocation strategies associated with different levels of water supply, optimistic-pessimistic attitude, and climate change and where the effort could be made towards regional sustainability; (3) dealing with fuzzy uncertainties simultaneously occurring in objective functions and constraints as well as tracking fluctuating attitudes of decision-makers. The effectiveness of proposed model was verified in a real-world case in Zhanghe Irrigation District, Hubei Province, China. The changing range of economic benefit, crop yield, energy production, and environmental impacts were obtained based on optimal water-land resources allocation under different confidence levels and risk attitudes. Results under climate change scenarios show that climate change exacerbated local water shortage, especially in RCP 8.5, which requires 4.24 × 10⁸ m³ of compensatory external water. Results also show that CO₂ emission contributed 94.9% of GHGs emission, while fertilizers application contributed to 58% of total CO₂ emission amount, calling for effective fertilizer utilization management. Compared with single objective models, proposed model performs better on providing coordinated policy solutions. The proposed approach can help manage resources in WORLD nexus system in a sustainable way, and is portable to other similar regions to promote sustainable development.