Although the Earth is 4.5 billion years old, modern humans have inhabited the planet for only about 200,000 years. The human population increased slowly initially, but recent growth has been explosive. Human actions now dominate the entire Earth system, ushering in an era referred to as the Anthropocene, which started in about 1750 with steam engines, industrialization, and the rapid rise in the use of fossil fuels.

During this era of the Anthropocene, humans have irreversibly transformed the geophysical and ecological systems of the planet, carving out a globally connected niche and causing complex societal challenges such as climate change, disasters, pandemics, food insecurity, invasive species, and biodiversity loss.

A new initiative co-led by John Little, the Charles E. Via, Jr. Professor of Civil and Environmental Engineering, is set to transform how we address these societal challenges. He is working alongside two co-principal investigators from the Department of Urban Affairs and Planning at Virginia Tech: Associate Professor Shalini Misra and Assistant Professor Theo Lim.

The plan is to take a system-of-systems approach.

“Natural scientists, social scientists, and engineers usually work on separate systems,” said Little. These can include land use, watershed, estuary, economic, and governance systems. “We develop models of these systems to help us understand them and then use the models to make predictions about how the separate systems behave.”

For example, Little said, researchers use their understanding of the watershed system to predict how climate change affects rainfall, which causes water and nutrient runoff that can reach estuaries. Similarly, an estuary model can predict how inflowing water and nutrients cause dead zones in the deep water that snuff out aquatic life. In turn, the land-use system can predict how population growth will increase impervious surfaces in urban areas, which increases runoff, and the economic system can predict how population growth increases the demand for agricultural products, which requires more fertilizer use in some areas and can increase runoff of nutrients. 

When addressing societal challenges of this era, however, it is important to understand how the separate systems interact with each other. “We need to connect the models creating a larger system that includes all of the separate systems, which we refer to as a system of systems,” said Little.

Little’s new endeavor, known as Convergent Anthropocene Systems, or Anthems, aims to validate the system-of-systems approach in the Chesapeake Bay Watershed. The $3.6 million project funded by the National Science Foundation will tackle several interconnected societal challenges, including eutrophication, agriculture impacts, and economic growth. Eutrophication is an overabundance of nutrients in the bay, which can lead to algae blooms that harm ecosystems by causing low oxygen dead zones and potentially releasing toxins.

The first phase focuses on regional models of land use, watershed, and economic systems, which collectively result in eutrophication. The second phase of the project will extend the computational framework to include estuary and governance models, zooming in to Baltimore at the urban scale.

“The system-of-systems model enables us to understand the connected systems and make predictions about how they behave,” said Little.

The project is led by Virginia Tech, but includes researchers from Stevens Institute of Technology, the University of Maryland, Baltimore County, the University of Nebraska, and Dartmouth College.

Over the course of five years, the team will work closely with the Chesapeake Bay Program, using the integrated modeling tools to examine synergies such as nutrient reduction and flood risk mitigation and tradeoffs such as nutrient reduction and fish productivity across multiple systems and scales.

“Anthems represents a crucial step toward understanding and mitigating Anthropocene challenges created by humans” said Little.

The systems-of-systems approach can be extended to include other societal challenges that have developed in the Anthropocene era, like the urgent need for a clean energy transition or preparing for and responding to disasters.  

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