NSF CAREER award recipient explores society’s competing interests at the interface between humans and the environment
Ethan Yang
Ethan Yang leads the Complex Adaptive Water Systems (CAWS) Research Group at Lehigh. (Photo credit: Douglas Benedict/Academic Image)

For a scholar recently honored by the National Science Foundation’s Faculty Early Career Development (CAREER) Program, Y.C. “Ethan” Yang’s professional goals seem almost anti-careerist.

“When PhD students train, they tend to focus narrowly,” says Yang, an assistant professor of civil and environmental engineering. “To publish, you need to be an expert—the only person who fully understands a specific topic.” Yang takes a broader view. “The world is complex and interconnected,” he says. “Your expertise may be specific and problem-driven, but it’s linked to other topics that the broader society cares about.”

It’s called nexus thinking—and it especially applies to the study of water, which was Yang’s narrow focus early in his academic life. “I didn’t want to focus entirely on natural processes or entirely on human society,” he says, “but rather on their intersection.” He didn’t realize at first that this would position him to study an area of emerging importance called the FEW—food, energy, water—nexus.

Yang’s undergraduate major was geography. “I was always interested in the interface between humans and the environment. Water is an obvious link because we need it to survive,” Yang says. That led to training in environmental engineering. “I wanted to build my capacity in quantitative methods,” he says. “When engineers calculate, they answer precise questions, like the capacity that a reservoir requires.”

But after earning his PhD in civil engineering, the pendulum of Yang’s interests began to swing toward humanistic matters. “Often, the reason we have an environmental problem is because society has an issue,” he says. “It has nothing to do with the natural environment. It’s because the human drive to compete often forces us to make decisions that are not necessarily good for the environment, other people, or even ourselves.” Yang started to look more deeply into psychology and social science to get at why and how people make decisions.

“The world will become only more complex. Students will need to test layered scientific questions and create interconnected solutions.”
Ethan Yang

Studying the FEW nexus demands insights and data from sources representing interests with different—often competing—values, goals, and priorities. In the field’s parlance, stakeholders are known as agents, and Yang’s innovation has been to attempt never-before-seen agent-based modeling to understand, forecast, or manage water usage. Such modeling would account for both the needs and motivations of disparate agents within a water system such as the Columbia River basin (U.S./ Canada) or the Mekong River basin (Southeast Asia). The two basins are the focus of an ongoing NSF-funded project on creating quantitative and computational modeling of complex FEW systems.

“People understand there’s a deep link between water and food,” Yang says. “But water is also essential for energy, with systems like cooling and hydro­power. Until a 2011 conference in Europe, people didn’t put all three together.”

Numerous gaps challenge the development of a comprehensive framework for studying the FEW nexus. “One is data,” Yang says. Agents often decide their water needs using different scales of space and time. A farmer might calculate water requirements for 200 acres over the next year. A utility might figure needs for half a state over the next 45 minutes.

Yang’s team and colleagues at the University of Houston are now developing an agent-based model that links food and water, while a team at George Washington University is working on an energy model that they hope can merge into a single framework. “It’s challenging to make these models talk to each other,” he says. “We’re not there yet.”

Yang’s newest research endeavor also involves agent-based modeling in another water-related application. The project funded by his CAREER award will study decentralized sustainable stormwater management using real-time data from an Internet-of-Things-connected green infrastructure network.

Recognition from the NSF helps confirm the relevance of Yang’s multi­disciplinary approach. “Nexus thinking is a good way to agitate for the next generation,” he says. “The world will become only more complex. Students will need to test layered scientific questions and create interconnected solutions to fix the problems they’ll face.”