Urban sustainability is about more than low-energy light bulbs, mass transit, and carbon footprints. It’s about how we manage the world’s growing urban impact. The fact that 51 percent of the population is now concentrated on only 2 percent of the planet means we need to design urban environments that have minimal impact on the ecosystem while also being resilient to external threats.
The scope of the challenge is neatly summed up by Northeastern law professor Lee Breckenridge, who says that urban sustainability “requires looking at how cities fit within ecosystems and how they depend on ecosystem dynamics both within and outside of city boundaries.”
Urban sustainability presents intertwined issues of environmental protection, economic viability, and social equity, she says. Cities cannot be sustainable over the longer term if their economic growth impairs the environment that they depend upon for clean air, fresh water, food supplies, and other ecosystem services. Globally, the sustainability of human life—including that of poor and vulnerable populations—requires both equitable distribution of economic resources and protection of a healthy environment.
As urban populations soar, cities face growing dangers of linked environmental, social, and economic crises. The issues are multifaceted and interconnected. Designing sustainable urban systems requires an interdisciplinary approach that incorporates scientific inquiry, technological innovation, legal coordination, and new policy ideas—just the direction in which Northeastern researchers are headed.
ALTERNATIVE ENERGY AND GREENER ENGINEERING
The science-based solutions coming out of Northeastern labs are focused on sustaining the urban infrastructure through resource conservation—saving both energy and infrastructure itself.
Northeastern researcher Sanjeev Mukerjee works in an area that often leads any discussion of sustainability— alternative energy. The chemistry professor, who heads Northeastern’s Center for Renewable Energy Technology, is working with colleagues at the university and in private industry to develop a catalyst for low-temperature fuel cells that is cheaper and more plentiful than the metals currently used, such as platinum.
Mukerjee says the ultimate goal of his work is to replace “all combustion-related power sources with an electrochemical energy conversion and storage system”—in short, a better battery that could revolutionize how we power all sorts of systems that are part of the urban landscape, from laptops to vehicles.
“Urban settings are becoming increasingly reliant on alternative energy,” says Andrew Myers, assistant professor of civil and environmental engineering, “and as such we need to understand the vulnerabilities of emerging alternative energy structures.” Myers’ research in wind turbine vulnerability bridges the gap between urban sustainability and urban resiliency.
“Traditionally, building design has focused on promoting the safety of life, and that’s what building codes are designed for. What they don’t do is ensure performance,” said Myers. Today, structural engineers are beginning to explore ways to minimize physical damage to the structures themselves, easing the impact of natural disasters on urban environments.
By modeling the resilience of various types of wind turbine designs against earthquakes and hurricanes, Myers hopes to minimize the uncertainty associated with these new types of structures.
Researchers are also looking at urban resiliency from a broader, resource-based perspective.
“I think structural engineers should own this space,” says civil and environmental engineering chair Jerome Hajjar. “The construction and use of commercial and residential buildings account for about 40 percent of our energy use, about 40 percent of our waste production, and about 40 percent of our greenhouse-gas emissions.” According to Hajjar, the industry is in need of transformative, cost-effective solutions and urban building needs to be at the top of the list.
Hajjar was recently awarded two new National Science Foundation grants with this effort in mind. One will look at the points at which energy is lost from a building and how novel materials could minimize that loss. Another will focus on steel structures built with materials that can eventually be disassembled and reused instead of demolished, eliminating a huge portion of the nation’s waste output. While many of those materials are now recycled, not sent to the dump, Hajjar’s team is focusing on the idea that reuse leads to less energy required for construction than recycling, as well as less waste.
“I’d like to try to kick things up a notch with a much richer level of understanding through analysis of the actual energy that goes into constructing structures and having that be integral to the design process,” says Hajjar.
PROTECTING URBAN INFRASTRUCTURE
In a post-9/11 world, urban sustainability means protecting the urban environment not just from natural disasters, but also from destructive attacks. Researchers like electrical and computer engineering professors Carey Rappaport and Michael Silevitch of ALERT—Northeastern’s multi-university Department of Homeland Security Center of Excellence—are implementing novel imaging techniques to minimize the possibility of terrorist attacks.
Standard imaging can’t answer the question: “What does a bag of explosives look like?” says Rappaport. But the wave-based imaging being developed in his lab can.
Engineering professor Sara Wadia-Fascetti is also using wave-based subsurface imaging—to probe the very foundations of our infrastructure for potential soft spots particularly vulnerable to physical stress. With a better understanding of the state of our roads and bridges, we’ll be better equipped to re-engineer them before it’s too late, she says.
There are probably infinite technical solutions to the problem of urban sustainability, adds Wadia-Fascetti. “But they aren’t going to be successful if we don’t have an impact on human behavior. We have to understand what drives human behavior and what drives it to change.”
POLICY SOLUTIONS IN COMPLEX SYSTEMS
This is where sustainability thought leaders like professor Matthias Ruth and associate professor Gavin Shatkin come into the picture. Their interdisciplinary approach looks at sustainability solutions in the context of whole systems and societies—really, the only way to look at them, says Shatkin, because “urban sustainability touches on every aspect of the interaction between people and the world they live in.”
“These are really complex systems,” says Ruth, who has joint appointments in the College of Engineering and the College of Social Sciences and Humanities. “What I’m trying to understand is how the different aspects play together, using computer modeling so that we can anticipate some of the undesired consequences of what we think are solutions.” That analysis needs to account for the impact on each area of a system— hydrology, energy, public health, economics, and even security.
For example, in Beijing, improvements in the power grid have led to increased air conditioning use. “Air conditioners actually heat up the environment and produce more air pollution,” says Ruth. “And then we’re not better off at all, because we’ve actually significantly changed the local environment. We often find that our interventions, when not fully thought through and properly implemented, result in outcomes that run counter to our intentions. The case of using more air conditioning as we heat up the urban environment is one of many where we seemingly get locked into unsustainable patterns.”
Asian cities are an area of particular concern for Shatkin, who notes that urban populations there are growing at tens of millions of people per year. Costly “new town” megaprojects, or planned cities, are among the leading approaches to dealing with this influx, but they have the potential to cause major ecological impact through increased vehicle use, increased consumption, and the conversion of agricultural land to urban use.
The megaprojects are also socially unsustainable for similar reasons. “These projects are premised on the desire to maximize economic growth,” says Shatkin, “yet this is a model of economic growth that concentrates the wealth in the hands of the wealthy”—promoting more consumptive lifestyles at the expense of lower-resource ones, like small farms and businesses.
“In my research, I am exploring the factors that are driving governments to pursue such projects,” despite their negative effects, he says.
RETHINKING THE COST OF CHANGE
It may just come down to a widespread belief held by many policymakers and ordinary citizens alike that the cost of sustainability outweighs the benefits.
But Ruth says that is a faulty calculus. If we embed all the costs of doing things the wrong way, he says, we’ll soon begin to realize that the high dollar cost of green practices is an illusion. For example, he proposes instituting regulations and economic incentives that more accurately reflect traditional energy’s true costs—such as climate change or international security. When we do this, he says, “then suddenly the alternatives don’t look so noneconomic anymore.”
Educating high-level policymakers, he says, is an obvious and important step. But working from the bottom up may be even more critical: “Probably the most impact I have is in how I teach and educate the next generation of decision leaders,” he says.
According to law and public policy professor and interim dean of the School of Public Policy and Urban Affairs Joan Fitzgerald, that education should focus on the synergistic potential of urban environments.
Their density has the potential to allow city residents to rely less on cars and more on energy-efficient land-use practices. But because policy areas are implemented with a fragmented, piecemeal approach, says Fitzgerald, “they don’t add up to a transformative strategy.”
In order for that next generation of decision leaders to successfully work toward the vision today’s researchers are starting to draw up, “they need to be able to think comprehensively about how all the systems in a city connect,” Fitzgerald says.
Architecture and urban landscape professor Jane Amidon offers an example of such comprehensive thinking.
“We can be doubling and tripling up on functionality in the way that we design our public spaces,” she says. For example, the Fresh Kills Landfill to Landscape project on New York City’s Staten Island incorporates outdoor recreational space with ecosystem rehabilitation.
“It’s not just the symbolism of a green public space, which costs a lot to maintain economically,” says Amidon. “It’s about new green infrastructure created from previously contaminated industrial use.”
Such projects are traditionally associated with the wealthier areas of a city, as they reflect higher real-estate values, but a truly sustainable city provides access to these resources across socioeconomic classes.
“We’re not just trying to re-create a natural condition,” she says, “but to understand how systems function and leverage them in an appropriate way, economically, socially, and environmentally.”
– By Angela Herring