Food, energy, and water are all critical for human well-being. There are challenges to meeting future human needs and demands for each resource, but their interconnectivity adds further complexity. In an article recently published in Reviews of Geophysics, D’Odorico et al.  explore the different components of the food‐energy‐water nexus and identify potential strategies for a more sustainable and secure future as we continue through the twenty-first century. Here, one of the authors describes the key areas of discussion in this field.
How would you describe the complexity of the food-energy-water nexus to a non-expert, and explain its significance?
The food-energy-water (FEW) nexus focuses on the interconnections among these three resources to investigate potential synergies or tradeoffs.
For example, growing crops for food requires water for irrigation and energy for harvesting. Further, the crops could be grown for biofuels instead of food and the irrigation water could instead be used to produce hydropower. Alternatively, the water could be used for the extraction of fossil fuels, such as shale oil and gas.
As a result of these, and many other interdependencies among food, water, and energy, a policy that affects one dimension can have unintended consequences for the others. Therefore, it is important to understand the linkages and potential tradeoffs so we can best meet society’s simultaneous food, water, and energy needs.
What are the key challenges of feeding a growing global population fairly and sustainably?
Tradeoffs between food production and the environment continue to grow. While there are a host of solutions to potentially address this dilemma, implementing these strategies – and linking food security science with policy in a specific place – remains an elusive next-step.
Another key challenge for feeding the world’s population is ensuring physical and economic access to sufficient nutritious food. Even in countries like the United States that have an abundance of food, many people suffer from under- and over-nutrition as calorie-dense and sugary foods are readily affordable. Policies that serve to make healthier foods (which also tend to have lower environmental impacts) more economically attractive and accessible can go a long way in promoting more equitable and sustainable consumption and production patterns.
The question is not just how much population will grow this century, but also how and what people will eat. There is growing evidence that changes in diets and food waste substantially contribute to the amount of crop calories required to meet demand in 2050. But navigating this is challenging because it depends on a variety of complex factors, including consumer behavior.
What should be the priorities for meeting future energy needs?
Energy is a very strong determinant of life quality and human development. Beyond a certain level of per capita energy consumption that corresponds to the basic primary energetic needs for electricity, heating, cooking and transport, there are no improvements in the quality of life and wellbeing of households. Therefore, we need to prioritize energy for development, while recognizing how energy production may compete with food production and environmental costs.
We should develop societies that emancipate themselves from environmentally destructive patterns of energy consumption such as burning fossil fuels and developing nuclear power plants. Interestingly, renewable energies such a wind and solar power are also the ones that are the least water intensive.
How does water availability influence human activities?
Water is fundamental for all elements of life, both for drinking and for the production of food, although water consumption for food production overwhelmingly exceeds drinking water needs.
Water availability is a major factor constraining humanity’s ability to meet the future food and energy needs of a growing and increasingly affluent human population.
Many water demanding human activities (such as irrigated croplands and mines) are located in arid or water stressed areas.
To overcome water constrains, in some areas water is procured with additional economic and environmental costs. Indeed, water is transported from farther away and/or is pumped from ancient nonrenewable aquifers.
Furthermore, climate warming is affecting water availability through a modification of evapotranspiration rates and precipitation patterns. Climate change and new water demanding human activities can exacerbate and/or induce water stress. Physical water scarcity can constrain human activities and/or create a competition for water resources allocation.
What are the main threats to food and water security?
Food and water security are indissolubly interconnected. With increasing demand, food and water security are some of the most urgent challenges for sustainable development.
Food insecurity is often due either to lack of natural resources (for example, land or water) to produce crops and livestock, or to institutional deficiencies that limit agricultural development.
The term water insecurity is often used with different meanings.
When it refers to drinking water, water insecurity is seldom due to lack of water resources but to lack of institutions that can provide safe drinking water. More generally, there are many countries that have the potential biophysical water availability to satisfy the societal demands but not the economic, technical and institutional conditions to use these resources. These are countries, for instance in Sub-Saharan Africa, where people often suffer from high levels of malnutrition. It is clear then that investments and resources are particularly important for water security and therefore for food security.
What strategies could be deployed to ensure a more secure and sustainable future?
There are clear ecological, material and energetic boundaries that need to be met for humanity to be able to live sustainably. The recently (re)launched Transforming our world: the 2030 Agenda for Sustainable Development presents “a plan of action for people, planet and prosperity” organized through 17 Sustainable Development Goals and 169 targets.
While many of these goals are “noble” and highlight some critical areas of development, what is often neglected is that many of these targets might be in competition with each other.
Our work tries to shed light on the tradeoffs and unintended consequences of policies aiming at achieving these goals. Societal decisions need to be taken with awareness and informed, democratic participation.
What are the challenges in shifting to a circular economy?
A circular economy is often considered as a panacea for the current wasteful patterns of resource consumption by human societies. However, the fact that we don’t have already a circular economy tell us that there are some major economic, energetic, and cultural impediments. It would be unrealistic to build the global economy on a closed loop of material-end energy flows between the economic and the natural systems.
Despite these limitations, the circular economy paradigm allows us to recognize that, even without complete recycling and reliance on renewable energy, systems of production that promote recycling, reuse, and refurbishing can reduce the footprint of human societies.
—Paolo D’Odorico, Department of Environmental Science, Policy and Management, University of California, Berkeley; email: [email protected]