Water, food, and energy are the most basic human needs and share a strong connection. Water is used to grow crops, drive hydropower generation, cool down thermoelectric power plants (generally fueled by coal, natural gas, or nuclear fission), and extract fossil fuels (e.g. through hydrofracking). Energy is required to extract groundwater, transport water resources where they are needed, treat wastewater, run desalination plants, plow and harvest fields, and refrigerate and transport harvested crops. Moreover, with the rise of biofuels, some crops are grown directly for energy generation, leading to important implications for water use and food prices. The strength of the links between water, energy, and food in a given region is affected by the relative abundance of the three resources, population density, and economic development of local communities.

Shortages in any of these three resources can cause severe monetary losses and even deaths in extreme circumstances. However, water resources are often the most problematic of the three for two key reasons: 1) water availability is largely determined by climate variability, and 2) we cannot transport water efficiently. While we have developed advanced weather and seasonal forecasts to anticipate water availability, we have ultimately very limited control on how much precipitation falls in a given year. Furthermore, we have trade networks and electricity grids that allow us to efficiently transport food and energy within and across continents, but water resources remain largely local to individual river basins. We can build infrastructure to transport water from one basin to another (e.g. the California State Water Project) but these projects are complex and expensive, limiting their proliferation and the distance that they can cover.

Given the variability and regional constraints on water resources, the need to efficiently allocate water across sectors using a systems-approach is clear. However, the two dominant systems frameworks for organizing the relationship between food, energy, and water vary widely in terms of benefits and limitations.

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