Article Type: ReviewFood and water security are one of the most critical subjects in all countries. Water deficiency is turning to a national crisis in Iran, due to climate change and non-optimal management of water resources. Due to the increase in water tensions, the national production will encounter major challenges which will lead to more dependency on importing foodstuff. It is notable that in the future, water deficiency will not be due to water shortage, but could be the consequence of the weakness in the regulations, inappropriate policies, and unplanned use of water resources. Accordingly, water governance in Iran has become a crucial concern in the context of increasing water deficiency, local and border water conflict, and global climate changes. Drying of water basins and the decline of groundwater is the result of the aforementioned regulations. Altogether, in the current situation of Iran, in order to guarantee the production of sustainable food products, considering the worsening state of water shortage, it is necessary to notice good governance, along with the empowerment of indigenous communities and the revival of their knowledge in areas related to the conservation and optimal utilisation of water resources. In this study, while addressing different dimensions of water governance and its role in water and food security, the innovative water governance methods have been described in the field of water security compared to conventional methods of integrated water resources management.

Today, scientific research on the types of Nexus, especially the water- energy- food Nexus as the driver of improving the welfare of society, is expanding. Since the Nexus approach is relatively new and requires the cooperation of several fields, explaining the concepts, its literature review, with a special focus on the water- energy- food Nexus is essential. This article aims to express Nexus approach simple and clear, by a detailed review of several related articles from 2011 to 2021. Articles were reviewed and categorized by year, source variety, and topic. So the outline of the formation of the Nexus approach, water- energy- food Nexus and the questions raised about this approach were codified in a way that provides a practical insight for policy making. In general, the Nexus approach, especially the water- energy- food Nexus which creates a very complex system and must be considered from a political, social and economic perspective, is difficult to implement. However, the Nexus approach is transitioning to an important component of development planning, and its success requires the guidance of strategic policies and institutional structures in multilevel governance. It seems that countries need to reform their governance structures in line with the Nexus approach. Another issue that has been considered in this article is the difference between the Water- Energy- Food Nexus approach with the approach of integrated water resources management. Due to the similarities, there are doubts about the need to move from integrated water resources management to Water- Energy- Food Nexus.

Using water-energy-food-environment (WEFE) nexus as the prism, this review explores evolution of groundwater governance in Iran, Saudi Arabia, Mexico, China, Bangladesh and India – which together account for two-thirds of the global groundwater-irrigated area. Global discourse has blamed widespread water scarcity squarely on supply-side policymaking and advocated a broader template of water governance instruments. Integrated Water Resources Management (IWRM) presented just such a template – with pricing, participation, rights and entitlements, laws, regulations, and river basin organizations – as additional water governance tools. However, the IWRM template faced disillusionment and pushback in many emerging economies. WEFE nexus, the new paradigm, prioritizes system-level optima over sectoral maxima by harnessing synergies and optimizing trade-offs between food, water, energy, soil, and eco-system sustainability within planetary boundaries. Realizing this vision presents a complex challenge in groundwater governance. Global groundwater economy comprises three sub-economies: (a) diesel-powered unregulated, as in Nepal terai, eastern India, Bangladesh, Pakistan Punjab and Sind, and much of Sub-Saharan Africa, where use-specific energy subsidies are impractical; (b) electricity-powered regulated, as in North America and Europe, where tubewells are authorized, metered and subject to consumption-linked energy charges; and (c) electricity-powered unregulated, as in geographies covered by our review – barring China, Bengal and Bangladesh – where unmeasured electricity subsidies have created a bloated groundwater economy. This last sub-economy represents the heartland of global groundwater malgovernance, least equipped to meet the sustainability challenge. It has an estimated 300 million horsepower of grid-connected electric pumps that are either unauthorized and/or unmetered and/or use free or heavily subsidized or pilfered power for irrigating 50–52 million hectares, nearly half of global groundwater-irrigated area. In (a) and (b), groundwater scarcity inspires water-energy saving behavior via increased energy cost of pumping. In sub-economy (c), users are immune to energy costs and impervious to groundwater depletion. Here, the WEFE nexus has remained blind to the irrigation realpolitik that catalyzes or constrains policy action. We explore why the political costs of rationalizing subsidies are prohibitive and exemplify how a smart transition from fossil to solar energy for pumping may offer an opportunity to turn the perverse WEFE nexus into a virtuous one.

The nexus of food, energy, and water systems (FEWS) has become a salient research topic, as well as a pressing societal and policy challenge. Computational modeling is a key tool in addressing these challenges, and FEWS modeling as a subfield is now established. However, social dimensions of FEWS nexus issues, such as individual or social learning, technology adoption decisions, and adaptive behaviors, remain relatively underdeveloped in FEWS modeling and research. Agent-based models (ABMs) have received increasing usage recently in efforts to better represent and integrate human behavior into FEWS research. A systematic review identified 29 articles in which at least two food, energy, or water sectors were explicitly considered with an ABM and/or ABM-coupled modeling approach. Agent decision-making and behavior ranged from reactive to active, motivated by primarily economic objectives to multi-criteria in nature, and implemented with individual-based to highly aggregated entities. However, a significant proportion of models did not contain agent interactions, or did not base agent decision-making on existing behavioral theories. Model design choices imposed by data limitations, structural requirements for coupling with other simulation models, or spatial and/or temporal scales of application resulted in agent representations lacking explicit decision-making processes or social interactions. In contrast, several methodological innovations were also noted, which were catalyzed by the challenges associated with developing multi-scale, cross-sector models. Several avenues for future research with ABMs in FEWS research are suggested based on these findings. The reviewed ABM applications represent progress, yet many opportunities for more behaviorally rich agent-based modeling in the FEWS context remain.