State of the Planet

News from the Columbia Climate School

The Big City, Subdivided for Sustainability

This article originally appeared in slightly different form on the website of the Columbia Data Science Institute.

Two-thirds of people on the planet will live in cities by 2050; by then, cities will be home to at least 6 billion people, the United Nations estimates. But few cities are prepared for this population boom. An upcoming research project will explore new, localized models for urban infrastructure—the roads, pipes and grids that move people, food, water and energy—to make cities cleaner, healthier and more enjoyable places to live.

By soaking up excess stormwater, tree pits planted with vegetation, help to reduce sewer overflows. Here, researchers Diana Hsueh and Rebecca Gibson of Lamont-Doherty Earth Observatory measure how much water this spot in the South Bronx can absorb. (Kim Martineau)

The project will be carried out by a consortium led by researchers at the University of Minnesota, Columbia University’s Earth Institute and the Georgia Institute of Technology. The $12 million research project is sponsored by the U.S. National Science Foundation.

In the past, governments built massive infrastructure projects for the public—interstate highways, regional power plants and centralized sewage treatment systems.  But concerns about climate change and the hefty costs of such monumental projects in dollars, pollution and vulnerability during natural disasters, have caused many to reconsider.

The city of the future may well favor small, local and decentralized solutions—what some planners call “distributed” infrastructure. Think roads geared towards bicycles instead of cars; houses powered by a neighborhood solar grid instead of a distant power plant; food grown on rooftops instead of shipped cross-country; and waste composted locally rather than piped to a sewage treatment plant or landfill.

By studying the infrastructure of cities in the United States and India, the so-called Sustainability Research Network will identify the best mix of local and regional systems to meet city dwellers’ needs. The team will also explore the community attitudes and public policies that allow cities to evolve and adapt.  Over the next four years, it will develop a framework for change based on new technologies and trends already underway. These include district energy systems, community solar energy, light rail, bike-share systems and urban farms.

The cities to be analyzed include New York, Minneapolis-St. Paul, Detroit and Atlanta, as well as cities in India with minimal infrastructure. The university researchers, in collaboration with their partners, will focus on developing practical solutions that can be scaled up and immediately put into action.

In New York City, researchers have worked with city government, property owners and local community groups to measure the impact of ongoing city initiatives to green the urban landscape by planting more trees and vegetation, including on rooftops and roadways. Trees and plants absorb rain and snow, reducing the amount of stormwater runoff that sewage treatment plants need to process. They also cool the air, helping to bring down temperatures on hot days. In addition to measuring the benefits of green infrastructure, Columbia researchers are studying the psychological factors that lead communities to care for city-planted trees and vegetation in their midst, protecting the public’s investment.

This research is still in progress, but initial results highlight the importance of involving neighbors in the stewardship of green infrastructure. Tree pits, for example, can absorb more stormwater if soils remain loose and uncompacted. Planting flowers in the tree-pits and putting up guards have proven effective at keeping foot traffic away.

Columbia’s role in the Sustainability Research Network will be to look at the potential for designated cities to scale up various sustainability solutions, be it planting rooftop farms or rewiring buildings for solar. How much capacity is there, and how big are the benefits? The researchers involved are: Earth Institute professor Patricia Culligan, deputy director of Columbia’s Data Science Institute; Upmanu Lall, a civil engineer who heads the Columbia Water Center; Vijay Modi, a mechanical engineer who heads the Sustainable Engineering Lab; Ben Orlove, an anthropologist who heads the Center for Research on Environmental Decisions; and Richard Plunz, an architect who heads the Urban Design Lab.

The shift to a city with local and decentralized services will require technology—sensors to pull in data from solar panels, weather stations and so on—and systems to analyze it, make decisions and coordinate with other systems. “The internet-of-things, where sensors talk to sensors, and make decisions without any human involvement, is going to be key for the city of the future,” said Culligan. “Sensors on green roofs will tell sensors controlling irrigation when plants are thirsty and need to be watered.”

“When it rains, green roof sensors will tell stormwater pipe sensors how much rainfall has left the rooftop so flows can be redirected to prevent flooding,” she added. “Big data and data science will be central to all of this.”

The project includes researchers who work with more than 29,000 cities in the United States and globally. Other partners include the University of Texas at Austin, Florida State University, University of Michigan, Colorado State University, Ohio State University. the Indian Institute of Technology-Madras, Ecolab, Xcel Energy, ICF International, ICLEI – Local Governments for Sustainability, the National League of Cities and the International City/County Management Association.

Directing the project is Anu Ramaswami, an environmental engineer at the University of Minnesota who works on sustainable urban systems and policy. Her co-investigators are Culligan and Amistead Russell, an environmental engineer at Georgia Tech who specializes in air quality and health.

Please see Sustainable Healthy Cities for a full list of project partners.

Columbia campus skyline with text Columbia Climate School Class Day 2024 - Congratulations Graduates

Congratulations to our Columbia Climate School MA in Climate & Society Class of 2024! Learn about our May 10 Class Day celebration. #ColumbiaClimate2024

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