Sky's the Limit

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Several years ago, professor of natural resources Marianne Krasny stood on the observation deck at the top of the Empire State Building, looking out over New York City. Among the crowded expanse of skyscrapers and lights and the uninterrupted flow of traffic below, Krasny saw vast areas full of possibility—the largely untapped terrain of Manhattan’s flat rooftops. Her first thought: solar panels.

Krasny is driven largely by her concern over climate change. Her work as director of the Civic Ecology Lab takes her into communities that have suffered from climate-related and other disasters, discovering urban stewards restoring the places they call home. It’s convinced her that urbanites have become the new caretakers of the land.

As we are increasingly a species of city-dwellers, Krasny’s perspective may prove to be crucial. Since May 2007, U.S. cities—comprising a mere 3.5 percent of the country’s total land area—have been home to more than half of the country’s population, according to the United States Census Bureau. And by 2050, a steady rise in global population and urbanization will likely add 2.5 billion people to the world’s cities. In the face of urban growth on this scale, how do we plan to feed, clothe, and provide energy and opportunities to people both inside and outside of our cities?

“I don’t have all the answers,” Krasny says, “but it’s time to fund local innovations that we can test by trial and error.”

Several CALS faculty members have set their sights on such urban innovations. With varied areas of focus, from climate change to food and social injustice to human health, they nevertheless agree that challenges related to these issues can be traced to the severe lack of space in increasingly population-dense cities.

“We need to get beyond the rhetoric about what it takes to have a sustainable city,” says Thomas Whitlow, associate professor in the School of Integrative Plant Science. “Cities require a much larger area of land to supply the resources necessary to support the city. So where is the tipping point? To maintain human health and well-being now requires a different kind of mindset.”

Conversations with faculty around CALS revealed consensus about one creative avenue for coping with the scarcity of urban land: Flat, uninhabited rooftops provide new terrain on which to build elements of healthy, sustainable urban communities. Far from being a novel idea, urban rooftops have been explored by the likes of scientists, farmers, and architects for years. From “green roofs,” which use living plant matter and soil to absorb, collect, and reuse rainwater that would otherwise pick up harmful pollutants as it runs off into local bodies of water, to rooftop farming and recreation, innovators have been tapping rooftop real estate to improve many aspects of people’s lives.

Now, CALS faculty with expertise ranging from landscape architecture to natural resources aim to advance these innovations. Operating within a Land-Grant college that focuses on environmental sustainability, health, and social justice across many disciplines, these CALS researchers are uniquely situated to adopt the new kind of mindset necessary to solve problems posed by increasing urbanization.

Here they discuss the innovative ways they are both using and envisioning urban rooftops, including healing communities after a disaster, providing equitable access to wireless Internet, and even saving lives.

Valerie Aymer: Build for Everyone

Valerie Aymer
Valerie Aymer. Photo by Robert Baker

Valerie Aymer, MLA’02, assistant professor of landscape architecture, has spent a lot of time thinking about how a rooftop could help mend the hearts and minds of a city after a terrorist attack. She collaborated on the design for the World Trade Center’s Liberty Park, a rooftop park overlooking the September 11 Memorial Plaza. The one-acre green refuge sits 25 feet above street level and opened to the public on July 29, 2016. It’s also the future home of the St. Nicholas Greek Orthodox Church, which was destroyed by the collapse of the south tower of the World Trade Center.

“This is one of the highlights of my career because I know that people from every walk of life will stroll through that park,” Aymer says. “And the memorial provides a welcoming, safe space for visitors and New Yorkers alike to gather, not only to reflect on 9/11 but also to contemplate hope for the future. I think that landscape has the ability to really heal a community.”

Aymer hopes that Liberty Park will encourage people to engage with the memorial and one another in a variety of ways. A central quiet area offers a retreat from the bustle of the city, and several park-top gardens attract visitors’ attention to the changing of the seasons. Whereas spring unfurls gently with ferns and the muted whites and pinks of hellebore, summer makes a loud splash with the vibrant reds and purples of gardenias and bee balm. The park was also designed to serve the diverse local community—Wall Street hedge fund managers, university students, neighborhood families—providing a welcome getaway for any purpose, from the workday lunch break to contemplation and remembrance.

Aymer pursued landscape architecture because she wants to make places for people—all people, and she challenges herself to keep a perennial problem in mind as she tackles each urban project: how to improve neighborhoods so that they provide the same quality and level of service that people can get in the suburbs without sparking gentrification. She would claim the rooftops for community spaces.

“There should be more use of rooftops for growing food as well as for recreation,” Aymer says. “Many marginalized communities don’t feel like they own the places where they live. If we can give them that sense of ownership, we have a better chance of creating stronger community spaces. Nobody wants to live in a place that is less than, and everybody should be equal. There’s no question.”

Marianne Krasny and Keith Tidball: Power Up and Prepare

Marianne Krasney and Keith Tidball
Marianne Krasny (photo by Chris Kitchen) and Keith Tidball (photo by Jason Koski).

Krasny and her colleague Keith Tidball, Ph.D. ’12, a natural resources senior extension associate, look to vacant lots and rooftops as fertile ground for cities facing climate change.

The pair coined the term “civic ecology” to describe spontaneous, community-driven efforts to renew blighted spaces.

“Civic ecology practices emerge in cities when people are living near a derelict space, like an abandoned lot or shoreline with a lot of litter or dumping,” Krasny says, “and they take initiative to restore the site by creating a community garden or holding a litter cleanup or removing invasive species and planting native ones.”

Often these projects tend to focus on greening efforts, notes Krasny. And from the standpoint of climate change, this makes her optimistic that these smallscale practices—if enough of them are occurring at many locations—can add up to a big difference for communities, with a caveat.

“I think it’s important that researchers in the university not just look at climate adaptation—coping with the changes in sea level and temperature—but look at it in a way that’s consistent with enhancing environmental quality, so that we can mitigate our carbon footprint at the same time that we’re adapting,” she explains.

Many urban stewards who engage in civic ecology practices strive to achieve the same balance between adaptation and mitigation. Nearly 20 years ago, the very first community garden Krasny visited in New York City—the Open Road Community Garden in Manhattan’s Lower East Side—was powering a small stream that youths had built on their site with a single solar panel.

“Ultimately, I wish climate change would go away. But I don’t think anyone knows how to do that,” Krasny admits. “Nevertheless, if cities like New York could be more self-sufficient in terms of energy—that would have a huge impact on slowing climate change. For example, there are so many flat roof surfaces in New York that could be used for solar panels.”

Based on Tidball’s research in New Orleans after Hurricane Katrina, Krasny’s idea is not too far from reality. After the hurricane, technologies designed to collect rainwater, harness solar energy, and create more energy-efficient heating and cooling systems were built into the roofs of demonstration houses in the Lower Ninth Ward. And their success sparked their implementation in residences throughout the city and well beyond, reducing the region’s carbon footprint and bolstering its resilience to weather-related disasters.

“Some of these developments ease rescue operations or provide people with almost a week’s worth of power while they wait for floodwater to subside, avoiding life-or-death situations such as those during Hurricane Katrina,” Tidball explains.

One could argue, he notes, that a chain of activity sparked by civic ecology activists opened the door for new ways of thinking about old cities. Throughout all of New Orleans, and even beyond Louisiana and Mississippi, a “rebirth movement” awoke as nonprofits sprang up to develop technologies based on lessons learned from the storm.

“Restoration does not always mean putting everything back as it was,” Tidball says. “It can also represent an opportunity to make things better. These rooftop technologies were designed for residential homes in flood-prone areas everywhere, and now they are there for the taking, with great potential to save lives.”

Lee Humphreys: Get Connected

Lee Humphreys
Lee Humphreys. Photo by Chris Kitchen.

Associate professor of communication Lee Humphreys ’99 studies how people integrate communication technology in their everyday lives, connecting to their peers and managing their own identities. This research has led her to see access to the information superhighway—ubiquitous community Wi-Fi on rooftops—as technological infrastructure for promoting equality.

Mobile access is power, Humphreys explains, and the world is increasingly divided into the digital haves—people with unlimited access to the Internet via Wi-Fi at home and at work—and the have-nots—those who can only access the Internet on their mobile phones and purchase data by the bit in data plans.

When someone is paying per bit, they are operating with a “metered mindset.” People with a metered mindset depend more heavily on access to Wi-Fi in public places. For example, students increasingly need the Internet for school assignments, and a metered mindset will produce a very different way of thinking about homework. Humphreys also cites the rise in “smarter” mobile technologies, which has enabled everyday users in and around cities to affect the condition of the urban infrastructure. If someone sees a pothole, they can document it through a mobile app, increasing the city’s responsibility to fix it. Yet this puts more of the power in the hands of those who can afford to be connected 24/7.

“We tend to think about Wi-Fi as something that every individual citizen gets for their homes, but as a result, there’s a lot of unused Wi-Fi availability,” Humphreys says. “Efforts to create community-based, shared Wi-Fi are already in motion, and that can better leverage access for all.”

Neil Mattson: Grow Food, Know Food

Neil Mattson
Neil Mattson. Photo by Chris Kitchen.

Food production is taking root in cities, from commercial rooftop greenhouses to indoor “vertical farms” in warehouses that maximize space efficiency by growing plants in layers from floor to ceiling. For Neil Mattson, associate professor in the School of Integrative Plant Science, the viability of these projects comes down to their carbon footprint. Mattson directs the college’s Controlled Environment Agriculture group, which aims to reduce New York state’s dependence on imported food.

“One of our research topics is looking at the carbon footprint of producing food in different ways,” he says. “Looking specifically at lettuce, strawberries, and spinach, we found that there’s a much smaller carbon footprint if they are fieldgrown in California and shipped to New York than if they are grown locally in greenhouses. We have more cloud cover and need to provide more supplemental light, which increases energy use.”

However, Mattson has been researching advances in lighting and greenhouse technologies that can reduce the carbon footprint of local greenhouse-grown produce. Efficient LEDs use less energy and can turn on and off in milliseconds in response to the temporary shade of a passing cloud—unlike the more commonly used high-pressure sodium lights that take 15 minutes just to warm up. LEDs also allow growers to adjust the light spectrum to make photosynthesis more efficient and improve crop quality.

New York is already second in the nation in controlled-environment agriculture, netting $27 million a year in wholesale income in the 2012 Census of Agriculture, and Mattson’s research has led him to conclude that of the options for growing food in the city, greenhouses are the best choice for environmental sustainability. Growing food in warehouses (or “plant factories”) requires artificial light—and HVAC systems to manage the heat produced by such light—creating a much higher carbon footprint.

While Mattson remains skeptical about the ability of urban agricultural practices to feed entire cities, he has seen firsthand the ripple effect community gardens can have on a neighborhood’s nutrition, particularly in food deserts where schoolchildren have only been exposed to a handful of common fruits and vegetables.

He cites the example of Harlem Grown, a community garden located in the middle of a Harlem food desert, which has shown him that the impact of exposing children to gardening goes far beyond diet. In addition to operating local urban farms, Harlem Grown provides garden-based development programs to Harlem youths. In turn, kids have been bringing home vegetables their parents can’t find in the grocery store, from mustard greens and dwarf kale to koji—and their parents have begun to request local bodegas carry them.

“Even if urban agriculture can only provide a small portion of our daily nutritional needs, the psychological and educational benefits are huge,” Mattson says.

Thomas Whitlow: Play Where the Air is Clear

Thomas Whitlow
Thomas Whitlow. Photo by Robyn Wishna.

Associate professor Thomas Whitlow in the School of Integrative Plant Science is no stranger to the bounty that can be reaped from rooftop farming, due in large part to his work on enhancing nutrient retention and reducing irrigation demand for Brooklyn Grange. Operating the world’s largest rooftop soil farms, located on two roofs in New York City, Brooklyn Grange grows over 50,000 pounds of organic produce per year. However, Whitlow’s research on street trees and air quality brings to mind a different use for rooftops: playgrounds.

For decades, Whitlow has been studying street trees—their levels of stress, survival in tough environments, and how to best transplant them. But his recent study of air quality on the summer streets of New York City led to some disappointing results. The trees were actually doing very little to reduce air pollution at street level.

Whitlow suspects the problem is that trees simply can’t handle the amount of pollution coming from sources near and far.

“In the face of the current pollution rates, the chances that natural processes are going to restore us to an equilibrium—an acceptably low level of equilibrium, which we had prior to the industrial revolution—that’s probably pretty slim,” he says.

Children are among the most vulnerable to pollution. Living near busy roads increases children’s risk of developing asthma, and asthmatic children exposed to higher levels of air pollution are more likely to develop symptoms of bronchitis, leading to measurable lung damage. And while street trees may not provide adequate protection, Whitlow discovered in a recent study at Brooklyn Grange that particulates could be up to 33 percent lower on the rooftop. Pondering a short-term way to protect children, Whitlow imagines building rooftop playgrounds so that children play where the air is cleaner.

When it comes to meeting all of the challenges posed by increased urban dwelling, Whitlow believes that the best solutions will require the most creative thinking.

“I don’t have any instant solutions aside from helping the current generation of students learn how to think,” he says. “But I’d like to see us be more involved in New York City because it’s a great test case. What did Frank Sinatra say? ‘If you can make it there, you can make it anywhere.’”