Across the globe, municipalities and their communities are responding to the challenges of making the sustainability transition. Two of these, Chattanooga and Curitiba illustrate the differences in motivation that can impel cities in differing locations and conditions to innovate. Chattanooga was driven to change by the economic, social and health impacts of chokingly high levels of industrial pollution. Within 10 years the city had turned itself around from being the ‘most polluted city’ in the USA to becoming its ‘sustainable development capital’. This story is having a powerful ‘demonstration effect’ on other cities. But if Chattanooga was a city that was forced to react, Curitiba is an example of a proactive city, an administration that planned for change rather than be overtaken by change. To be sure, neither city is sustainable in the full sense of the word: they both have large ecological footprints, there is still racial division and urban sprawl in Chattanooga, and poor sanitation and squatter settlements in Curitiba. But both cities are unlearning old ways and learning new ways in partnership with their communities and this is the essence of the sustainability challenge.

Chattanooga, Tennessee: Belle of the Sustainable Cities Ball

[Figure 1] The John Ross Bridge, in Chattanooga, Tennessee.

Fifty years ago the US government labeled Chattanooga, Tennessee, the dirtiest city in America. Today the city is hailed as a sustainability success story by the President’s Council on Sustainable Development. Chattanooga’s turnaround has inspired communities worldwide and the former manufacturing centre is now selling itself as a world leader in the sustainable cities movement. In a matter of decades, the city of 150,000 has transformed its city centre into a prime job centre and bustling tourist attraction (with a state-of-the-art aquarium); created a revitalized waterfront to which birds are now returning; re-used a former Army facility, once the largest producer of TNT worldwide, as a manufacturing site for electric buses; is attracting clean industry through the development of an ecoindustrial park; and is experimenting with ‘zero-emission’ manufacturing processes. The secret of Chattanooga’s success lies in visionary civic leaders, a committed and engaged local population, public private partnerships and adventurous financial investors willing to fund a series of environmental innovations. The process began in 1984 when city residents ‘responded to a planning initiative by saying that they wanted more than a strong local economy. They wanted to go fishing without driving out of town, and to be able to eat the fish they caught without worrying about their health’. This led to a visioning process, Vision 2000, which brought together city residents from all walks of life to identify the city’s problems — and to find solutions. Forty goals, ranging from providing affordable housing to river clean-up, were set. Pre-existing urban revitalization initiatives fed into, and were transformed by, this process of ecology-based urban renewal. The experimentations continue and the city has adopted sustainable development as its motto — expressed in the shorthand ‘equity, environment and economy’. This has become its unique selling point. While Chattanooga’s gains are impressive, whether its performance can live up to its marketing claims over time remains to be seen. The city still suffers from chronic urban sprawl and the loss of habitat and agricultural land as do most U.S. cities.

Curitiba, Brazil: A Laboratory for Sustainable Urban Development

[Figure 2] Historic center of Curitiba.

Curitiba is one of the fastest-growing industrial cities in Brazil with a population of over 2.1 million. Yet, compared to other cities its size, Curitiba has significantly less pollution, no gridlocked city centre, a slightly lower crime rate and a higher educational level among its citizens. The city is held up as an example of far-sighted and unconventional planning. For example, its ‘design with nature strategy’ has increased the amount of green space per capita (during a period of rapid population growth), and its mass transit strategy has cut total travel time by a third for its citizens, and contributed to the city having one of the lowest rates of ambient pollution in the country. Curitiba’s success lies in the gradual institutionalisation (over a period of 30 years) of urban development policies explicitly favoring: public transport over private automobiles; appropriate rather than high-tech solutions; innovation with citizen participation instead of master planning; incentive schemes to induce changes in business , household and individual behavior; and labor-intensive approaches rather than mechanization and massive capital investment. Such policies were officially adopted in the 1970s by Jaime Lerner, a visionary mayor who was also an architect and planner, and have helped pre-empt the usual growth-related problems faced by comparable cities. Among Curitiba’s innovative features are: ·

• transport — an express bus-based transportation system, designed for speed and convenience which is also self financing, affordable, wheelchair-accessible, and offers balanced routes;
• solid waste — a garbage-purchase programme which pays low-income families in bus tokens or food in exchange for waste; more than 70% of households also sort recyclable materials for collection;
• housing — a low-income housing programme with ready access to jobs in Curitiba’s Industrial City (which generates one-fifth of all jobs in the city; polluting industries are not allowed).
• incentives — provision of public information about land to fight land speculation;
• environmental education — free, practical short courses for workers and residents on the environmental implications of their work are offered by Curitiba’s Free University for the Environment.