Efficient use of water and nutrients in crop production are critical for sustainable water and crop production systems. Understanding the role of humans in ensuring water and nutrient use efficiency is therefore an important ingredient of sustainable development. Crop production functions are often defined either as functions of water and nutrient deficiency or are based on economic production theory that conceptualizes production as a result of economic activities that take in inputs such as water, capital and labor and produce crop biomass as output. This paper fills a gap by consistently treating water and nutrient use and human agency in crop production, thus providing a better understanding of the role humans play in crop production. Uptake of water and nutrients are two dominant biophysical processes of crop growth while human agency, including irrigation machine power, land-preparing machine power and human labor force, determine limits of water and nutrient resources that are accessible to crops. Two crops, i.e., winter wheat and rice, which account for the majority of food crop production are considered in a rapidly developing region of the world, Jiangsu Province, China, that is witnessing the phenomenon of rural to urban migration. Its production is modeled in two steps. First water and nutrient efficiencies, defined as the ratios of observed uptake to quantities applied, are modeled as functions of labor and machine power (representing human agency). In the second step, crop yields are modeled as functions of water and nutrient efficiencies multiplied by amounts of water and fertilizers applied. As a result, crop production is predicted by first simulating water and nutrient uptake efficiencies and then determining yield as a function of water and nutrients that are actually taken up by crops. Results show that modeled relationship between water use efficiency and human agency explains 68% of observed variance for wheat and 49% for rice. The modeled relationship between nutrient use efficiency and human agency explains 49% of the variance for wheat and 56% for rice. The modeled relationships between yields and actual uptakes in the second step explain even higher percentages of observed the variance: 73% for wheat and 84% for rice. Leave-one-out cross validation of yield predictions shows that relative errors are on average within 5% of the observed yields, reinforcing the robustness of the estimated relationship and of conceptualizing crop production as a composite function of bio-physical mechanism and human agency. Interpretations based on the model reveal that after 2005, mechanization gradually led to less labor being used relative to machinery to achieve same levels of water use efficiency. Labor and irrigation equipment, on the other hand, were found to be complimentary inputs to water use efficiency. While the results suggest interventions targeting machinery are most instrumental in increasing wheat productivity, they may exasperate rural – urban migration. Policy strategies for alleviating rural-urban migration while ensuring regional food security can nonetheless be devised where appropriate data are available.

The United Nation Sustainable Development Goals emphasized to meet the global food security challenges by mechanized farming; access of clean water challenges by renewable freshwater withdrawals; clean energy issues determined by clean fuel and cleaner technologies; and combat climate change by limiting anthropogenic emissions of carbon, fossil fuel, and Greenhouse Gas emissions in the air. This study examined the aforementioned United Nation Sustainable Development Goals in the context of Pakistan by using a time series data from 1970 to 2016. The study employed Tapio’s elasticity of decoupling state to analyze the relationship between water-energy-food resources and carbon-fossil-greenhouse gas emissions in a given country context. The results of Tapio elasticity found that carbon-fossil-greenhouse gas emissions’ contamination in water-energy-food’s resources are quite visible that exhibit weak decoupling state, expensive negative decoupling state, and strong decoupling state in the different decade’s data, which substantiate the ecological cost in water-energy-food’s resources. The results emphasized the need to adopt different sustainable instruments in a way to limit carbon-fossil-greenhouse gas emissions in water-energy-food resources through cleaner production technologies, renewable energy mix, environmental certification, anti-dumping tariff duty, strict environmental regulations, etc. These instruments would be helpful to achieve environmental sustainability agenda for mutual exclusive global gains.

Sustainability scholars increasingly recognise that environmental and security challenges that societies face today cannot be understood in isolation from one another. The rising popularity of a nexus approach to water–energy–food–environmental security analysis reflects this trend. Yet, little is known about exactly how previously disconnected scholarship on water security, energy security, food security and environmental security have converged in this way—and how this convergence can become more holistic and analytically meaningful. This paper outlines major conceptual turns within the literature on these four concepts and reflects on the use of nexus analysis in sustainability science as well as ways forward from where we currently stand. A salient finding is that while a nexus approach suggests more integrated analyses, there is still a tendency for siloed approaches focussed on how, for example, water security connects to energy and food security rather than truly integrated approaches.

Many regions in Africa and the Middle East are vulnerable to drought and to water and food insecurity, motivating agency efforts such as the U.S. Agency for International Development’s (USAID) Famine Early Warning Systems Network (FEWS NET) to provide early warning of drought events in the region. Each year these warnings guide life-saving assistance that reaches millions of people. A new NASA multimodel, remote sensing–based hydrological forecasting and analysis system, NHyFAS, has been developed to support such efforts by improving the FEWS NET’s current early warning capabilities. NHyFAS derives its skill from two sources: (i) accurate initial conditions, as produced by an offline land modeling system through the application and/or assimilation of various satellite data (precipitation, soil moisture, and terrestrial water storage), and (ii) meteorological forcing data during the forecast period as produced by a state-of-the-art ocean–land–atmosphere forecast system. The land modeling framework used is the Land Information System (LIS), which employs a suite of land surface models, allowing multimodel ensembles and multiple data assimilation strategies to better estimate land surface conditions. An evaluation of NHyFAS shows that its 1–5-month hindcasts successfully capture known historic drought events, and it has improved skill over benchmark-type hindcasts. The system also benefits from strong collaboration with end-user partners in Africa and the Middle East, who provide insights on strategies to formulate and communicate early warning indicators to water and food security communities. The additional lead time provided by this system will increase the speed, accuracy, and efficacy of humanitarian disaster relief, helping to save lives and livelihoods.

La seguridad del agua y la seguridad alimentaria están estrechamente vinculadas, y los actuales niveles de hambruna mundial y el crecimiento de la población requieren una mayor capacidad agrícola, impulsada en gran medida por la expansión de los cultivos de regadío. El presente documento se enmarca en el proyecto MADFORWATER, del que se extrajo gran parte del apoyo para llevar a cabo esta labor a nivel teórico y metodológico. El estudio tiene por objeto poner de relieve la importancia del agua en la configuración de la seguridad alimentaria, especialmente para los países en desarrollo de Asia y África, que representan el 70% de las tierras secas del mundo. El agua como factor clave en la agricultura y, por consiguiente, en la seguridad alimentaria, requiere un análisis específico para comprender sus interdependencias con los alimentos y, de ese modo, ampliar la comprensión para una gestión adecuada del agua. En este estudio se examinó la bibliografía existente hasta la fecha sobre los vínculos entre el agua y la seguridad alimentaria y se elaboró un índice (Índice de Seguridad Alimentaria-Agua - FWSI) para evaluar la forma en que la seguridad alimentaria se vio influida por factores relacionados con el agua en 36 países de África y Asia durante el período 2000-2015. La ponderación de los diferentes indicadores incluidos en el índice se obtuvo sobre la base de un cuestionario, distribuido a 54 expertos internacionales en tierras secas que participan en el programa Action COST "Drylands facing change". Los datos se obtuvieron de una amplia base de datos de organizaciones internacionales reconocidas como la FAO, el Banco Mundial, la Organización Mundial de la Salud, World Global Indicators y el UNICEF. Los resultados muestran que los países asiáticos con escasez de agua han realizado mejoras más regulares en los dos últimos decenios que los de África, donde los progresos son muy desiguales y el agua, entre otros factores, ha desempeñado un papel importante en la lucha contra el hambre. Al otorgar un papel fundamental al agua, el indicador ha logrado acercarse a un concepto de seguridad alimentaria más amplio que el tradicionalmente utilizado -más centrado en los criterios alimentarios- mostrando claras interrelaciones entre ambas dimensiones. Encontramos que las regiones con mayores niveles de desnutrición son también las que presentan mayores niveles de estrés hídrico. Se ha demostrado que el FWSI es un indicador sólido para complementar la explicación del hambre en el mundo.

The water-energy-food (WEF) nexus is the subject of much research focusing on different aspects, a wide range of issues, and development of a variety of models and tools. This study takes a different approach by developing a holistic framework that concentrates on the spatial elements of continuity and change associated with WEF transition on national, regional, and international scale. The study also investigates the interconnected challenges that could affect these resources and the actions and polices that should be taken on different geographical scales to address these challenges. The results can help practitioners and policy makers gain a clearer understanding of the state of the knowledge when performing WEF nexus assessments at different geographical scales.