Sustainable cities are the solution

by David Lepeska



New York mayor Michael Bloomberg unveiled a $25m, energy-efficient office building on the Brooklyn waterfront a few months back. The Perry Avenue Building features solar panels, rainwater-fed toilets and six rooftop windmills, which will produce 10% of its energy supply. "Wind power in this city," said the mayor, "is one of the solutions to our problem."

That problem – devising more sustainable cities – has rightfully drawn a great deal of attention of late. In February, Barack Obama created the White House office of urban affairs and quickly set about staffing it with experienced urban planners, to complement what many have called his "green dream team" on environmental policy.

Earlier this year in Strasburg, Obama acknowledged that the US bears the brunt of the responsibility for climate change. Combined with nearly $50bn in infrastructure spending in the stimulus package, the new administration's emphasis on building better cities is clear.

As for New York, the new Brooklyn building is part of a $250m programme to make Brooklyn's Navy Yard a hub for green industry, just one aspect of the mayor's broader plan to make the city more eco-friendly. When he launched PlanNYC two years ago, Bloomberg pointed out that the world's cities were responsible for 80% of global greenhouse gas emissions. Former US president Bill Clinton and UN officials have quoted the same figure.

This bit of data would mean city dwellers emit nearly four times as much as their rural counterparts. (The UN estimates that humanity became more urban than rural in 2008. Right now, the global populations of urban and rural folk are roughly the same.) Put another way, living in a city is almost four times as polluting as living outside of one.

Thankfully, the figure turns out to be wildly inaccurate.

The carbon footprint of urban dwellers is relatively light, says a report by David Dodman in the April issue of Environment and Urbanisation. Dodman, a researcher at the International Institute for Environment and Development, examined emissions reports from cities in the Americas, Asia and Europe.

He found that New Yorkers emit a third less greenhouse gases than the average American and that Barcelonans and Londoners emit about half of their national averages. And urban Brazilians are truly green: the residents of Sao Paolo and Rio de Janeiro are responsible for only one-third the national emissions average. Dodman's paper complements an earlier study by IIED senior fellow David Satterthwaite, who argued that cities emit about 40% of all greenhouse gases, as opposed to the oft-cited 80%.

On average, then, people who live in small towns and rural areas emit 50% more greenhouse gases than city folk. That cities may be part of the solution, however, does not mean that efforts like Bloomberg's PlanNYC are misplaced. Precisely the opposite is true.

By 2050, some 70% of us will live in urban settings, and it will ultimately be well-managed urban environments, with smart, energy-efficient buildings, power systems, transport and planning, that will save us from ourselves. Seeking better ways to do precisely that, a constellation of designers, architects and academics gathered at a conference on "ecological urbanism" at Harvard University's Graduate School of Design earlier this year.

Mitchell Joachim, who teaches architecture and design at Columbia University and was selected by Wired magazine as one of 15 people Obama should listen to, presented his vision for a collapsible and stackable electric city car, which would hang at public recharging stations, available for shared use.

He also explained "meat tectonics". Aiming to use meat proteins developed in a lab as building material, Joachim presented a digital rendering of an armadillo-shaped, kidney-coloured home. "It's very ugly, we know that," he said. "We're not sure what a meat house is supposed to look like."

Dorothee Imbert, associate professor in landscape architecture at Harvard, pointed to urban farming, a trend that has taken root in Detroit, New York, Milwaukee and a handful of international cities. Imbert mentioned her own student-assisted organic farms in Boston, yet acknowledged that adequate food supplies for future cities "would require rethinking of landscape in the building process".

Pritzker-winning Dutch architect Rem Koolhaas is thinking regionally. The Harvard professor and designer of the MC Escher-esque CCTV building in Beijing talked about his Zeekracht ("sea power" in Dutch), a plan for oceanic wind farms across the North Sea that would provide energy to much of northern Europe. With its constant high winds, shallow waters and advanced renewable industries, Koolhaas believes the North Sea offers energy potential approaching that of Persian Gulf oil.

His plan, which includes production belts in a half-dozen urban centres on or near the sea, energy cooperation and clean-tech research centres, is the type of project that, ideally, will both preserve green spaces and increase urban sustainability.

Another is a recently approved high-speed rail project in California, which will link that state's southern and northern hubs. Obama's stimulus package contains $8bn for high-speed and urban rail projects. That amount is nowhere near enough to install networks on a European scale, but, like windmills on the Brooklyn waterfront, it's a step in the right direction.

Henry David Thoreau moved to Walden Pond "to live deliberately", as he put it. But shortly thereafter the American naturalist and philosopher accidentally burned over a hundred acres of pristine Massachusetts woodlands. We can no longer afford to be like Thoreau. If we want to continue to romanticise our natural world, we, as a civilisation, must also avoid it.

Building More Sustainable Cities

By William E. Rees

London, Paris, Rome, New York. If civilization needed an icon, “the city” would be it. Half of humanity now lives in urban areas, a figure heading for 75 percent in coming decades.

Or maybe not. The sprawling North American city in particular is a product of the cheap energy and profligate consumption of a materially exuberant age that is rapidly coming to an end. Cities may well confront a triple specter of climate change, scarcity of energy and resources, and broken supply lines. Even the generally conservative U.S. National Intelligence Council (NIC) recently predicted that global demand for energy, food and water could easily outstrip supplies over the next decade or so, triggering trade-disrupting international conflicts.

This is unfamiliar ground. Since World War II, politicians and planners have shaped cities with no regard for resource use or ecological concerns. Today’s land-grabbing, auto-dominated, fuel-inefficient metropolises have evolved into parasitic black holes, sucking in excessive megatons of energy and materials from all over the globe and spewing out volumes of (often toxic) waste. In North America, buildings and urban infrastructure account for 40 percent of material consumption and a third of energy use. High-income cities have an ecological footprint—the dispersed area of land and water required to supply their needs and assimilate their wastes—that is several hundred times larger than their political areas.

All this must change. Climate science indicates that to have even a chance of avoiding a catastrophic increase in mean global temperature, the worldwide economy must be largely de­carbonized by 2050. The NIC argues that the U.S. should actually complete its transition by 2025. Such goals pose an unprecedented challenge to urban authorities at all levels.

To begin to meet that challenge, state and municipal governments must create the land-use legislation and zoning bylaws that urban planners need to consolidate metropolitan areas and smartly raise their density. Compact cities can boost their inherent urban efficiencies to unprecedented heights by exploiting the following characteristics:

• A high proportion of multiple-family housing, which reduces per capita consumption of land, infrastructure and just about everything else.
• Multiple options for recycling, reuse and remanufacturing of materials, along with skilled people for those activities.
• Car-free mobility, through investments that make walking, cycling and public transit viable.
• Co-generation of electricity and use of industrial waste heat to reduce per capita energy consumption.
• Improved livability with cleaner air, easy access to amenities, and a greater proximity of shopping and employment.

Efficiency gains are not enough, however. Sustainability and security demand that cities become more self-reliant. Urban designers must rethink cities as complete ecosystems. The most resilient option might be a bioregional city-state in which a densely built-up core is surrounded by supportive systems. Without becoming isolationist, such bioregions would produce much of their own food, fiber and water and recycle their waste. By being less reliant on imports, they would be partially insulated from climate vagaries, global resource shortages and distant military conflicts. And because inhabitants would depend on local ecosystems, they would have a powerful incentive (currently absent) to manage their resources more sustainably. The aggregate effect would be global sustainability.

Seem over the top? Perhaps. But our rethinking of cities must match the challenge. Scientists are deeply worried; you should be, too. If we can’t save our cities, we won’t save ourselves.

Note: This article was originally printed with the title, "More Sustainable Cities".

Curitiba: A Model Sustainable City

Curitiba is a city in southern Brazil and the capital of Paraná state since 1854. It was founded in 1654 as a gold-mining camp. From the early 19th century it received many German, Italian, and Polish settlers, and immigration continued during the 20th century with the arrival of Syrians and Japanese, as well as a massive influx of internal migrants from rural areas. The bus system of Curitiba, Brazil, exemplifies a model Bus Rapid Transit (BRT) system, and plays a large part in making this a livable city. The buses run frequently—some as often as every 90 seconds—and reliably, and the stations are convenient, well designed, comfortable, and attractive. Consequently, Curitiba has one of the most heavily used, yet low-cost, transit systems in the world. It offers many of the features of a subway system—vehicle movements unimpeded by traffic signals and congestion, fare collection prior to boarding, quick passenger loading and unloading—but it is above ground and visible. Around 70 percent of Curitiba’s commuters use the BRT to travel to work, resulting in congestion-free streets and pollution-free air for the 2.2 million inhabitants of greater Curitiba.

Curitiba’s Master Plan integrated transportation with land use planning, calling for a cultural, social, and economic transformation of the city. It limited central area growth, while encouraging commercial growth along the transport arteries radiating out from the city center. The city center was partly closed to vehicular traffic, and pedestrian streets were created. Linear development along the arteries reduced the traditional importance of the downtown area as the primary focus of day-to-day transport activity, thereby minimizing congestion and the typical morning and afternoon flows of traffic. Instead, rush hour in Curitiba has heavy commuter movements in both directions along the public transportation arteries.
Other policies have also contributed to the success of the transit system. Land within two blocks of the transit arteries is zoned for high density, since it generates more transit ridership per square foot. Beyond the two blocks, zoned residential densities taper in proportion to distance from transit ways. Planners discourage auto-oriented centers and channel new retail growth to transit corridors. Very limited public parking is available in the downtown area, and most employers offer transportation subsidies, especially to low-skilled and low-paid employees.

The popularity of Curitiba’s BRT has effected a modal shift from automobile travel to bus travel. Based on 1991 traveler survey results, it was estimated that the introduction of the BRT had caused a reduction of about 27 million auto trips per year, saving about 27 million liters of fuel annually. In particular, 28 percent of BRT riders previously traveled by car. Compared to eight other Brazilian cities of its size, Curitiba uses about 30 percent less fuel per capita, resulting in one of the lowest rates of ambient air pollution in the country. Today about 1,100 buses make 12,500 trips every day, serving more than 1.3 million passengers—50 times the number from 20 years ago. Eighty percent of travelers use the express or direct bus services. Best of all, Curitibanos spend only about 10 percent of their income on travel—much below the national average.