Depletion of natural resources needs quantification and efficiency analysis of the use of resources to improve sustainability. This paper evaluates the efficiency of Organization for Economic Co-Operation and Development (OECD) countries in terms of Water-Energy-Land-Food (WELF-Nexus) to ensure sustainability and environmental viability for both present and future generations. An input-output index system is built at a transnational level. Composite and intrinsic indicators are introduced to incorporate the interconnections and tradeoffs between sectors of the nexus and outcomes of the nexus. The nonparametric benchmarking order-α model, resulting from Data Envelopment Analysis (DEA) is used to estimate WELF-Nexus efficiency of each country, and to alleviate the intricacies of using composite and intrinsic indicators. To ensure resource generativity, an output target setting model that accommodates predefined input is proposed. Results show variation in performance among OECD members, with an annual average efficiency score of 68%, 69% and 78% in 2007, 2012, and 2016. Sensitivity analysis was performed to measure the effect of drought on WELF efficiency, a decrease of about 13% on average WELF efficiency was observed. Outputs improvement was recommended for each country: Lithuania (14%), Mexico (10%) and 11% for Hungary, Latvia, and Turkey due to their high inefficiency. The study provides a robust framework for policy making and shows that a win-win strategy for the nexus must be implemented to achieve WELF-Nexus efficiency, given the trade-offs within its sectors. Furthermore, it highlights that innovative-driven policies will enhance WELF-Nexus efficiency and sustainability.

Nowadays, food production systems play a relevant role as the steady increase of global population and food demand. The water-energy-food (WEF) nexus is a suitable approach to tackle resources management associated with these three pillars recognizing synergies and trade-offs. Different approaches have been used in the literature to measure the WEF nexus, being material flow analysis (MFA) and life cycle assessment (LCA), two of the most proven methodologies. The MFA approach is based on the amount of resources consumed, while using the LCA perspective considers all flows of the system (LCA footprints approach) or considering only the flows associated with water, energy, and food pillars as the inventory data (WEF-LCA approach). This manuscript compares the three mentioned approaches to identify their strengths and weaknesses. To do this, a sample of 100 Spanish dairy farms is analysed, where a single WEF nexus index (WEFni) is obtained using Data Envelopment Analysis. Results show that only four farms achieved a WEFni equal to 100 in all approaches, while the main difference between them is the number and type of resources considered for calculating the WEF nexus, which could imply a partial identification of hotspots of food systems.

The fishing sector constitutes an important source of economic revenue in northern Spain. In this context, various research studies have focused on the application of the five-step Life Cycle Assessment (LCA) and Data Envelopment Analysis (DEA) methodology to quantify environmental impacts of fishing systems. However, some of them have used environmental indicators that focus on individual environmental issues, hindering the goal of achieving integrated resource management. Therefore, in this study, the Water-Energy-Food (WEF) Nexus is employed as an integrative perspective that considers the synergies and trade-offs between carbon footprint, energy requirements, and water demand. The main objective of this study is to evaluate the operational efficiency and environmental impacts of Cantabrian fishing fleets. To this end, the combined use of LCA and DEA, along with the WEF Nexus, was applied to the Cantabrian purse seine fleet. DEA matrices were generated using the LCA-derived WEF nexus values as inputs to calculate efficiency scores for each vessel. Subsequently, based on the efficiency projections provided by the DEA model, a new impact assessment was performed to understand the eco-efficiency and potential environmental benefits of operating at higher levels of efficiency within this fleet. The average efficiency of the fleet was above 60 %. Inefficient units demonstrated a greater potential to reduce their environmental impacts (up to 65 %) by operating according to efficiency projections. Furthermore, the results revealed a strong dependence of environmental impacts on one of the operational inputs, i.e., fuel consumption. These findings highlight the significance of embracing holistic approaches that combine technical, economic, and social factors to achieve a sustainable balance in fisheries systems. In this regard, the five-step LCA + DEA method applied in conjunction with the WEF Nexus emerged as a suitable tool for measuring operational and environmental objectives. | This work was supported by the EAPA_576/2018NEPTUNUS project. The authors would like to acknowledge the financial support of Interreg Atlantic Area. Furthermore, the authors are grateful for the funding of the Spanish Ministry of Science and Innovation through the SMARTFOODPRINT project (PID2022-137023OB-C31) (AEO/FEDER, UE). We also want to thank the fishermen and those responsible for the processing plant for the provision of the data. Eva Martínez-Ibanez is grateful for funding through the FPI predoctoral fellowship (PREP2022- 000784)