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The application of the concept of sustainable development to cities is similar to its application to the global system as a whole. It is clear that cities have sources and sinks, and that people living in them utilize resources and generate pollution, just as in the case of the global system. The main difference between cities and the global system is that the former are not fully closed systems. That is, unlike the global system, cities can import resources and export pollutants. However, these importing and exporting activities have limits. For example, the trucking of garbage to landfills outside of a city becomes increasingly costly, the farther from the city the landfills are located and the importation of fresh water to replenish a city's depleted aquifers becomes increasingly costly, the greater the distance the water must be piped. Thus, as with all real social systems, cities have limited carrying capacities. If the carrying capacity of a city is eroded, it becomes increasingly difficult, if not impossible, to create a sustainable environment. As in the case of the global system as a whole, sustainable cities must not use resources faster than they can be replenished or substituted for, nor generate pollution faster than it can be naturally assimilated. Further, the infrastructure (carrying capacity) of a sustainable city must be able to support the current needs of its population - particularly its poorest citizens. If these criteria are followed, the ability of future generations to meet their needs will not be compromised. The world’s cities take up just two percent of the Earth’s surface, yet account for roughly 78 percent of the carbon emissions from human activities, 76 percent of industrial wood use, and 60 percent of the water tapped for use by people. These figures suggest that the struggle to achieve an environmentally sustainable economy will be won or lost in the world’s urban areas. Urban systems are undermining the planet’s health and failing to provide decent living conditions for millions of people. London, for example, now requires roughly 58 times its land area just to supply its residents with food and timber. Meeting the needs of everyone in the world in the same way that the needs of Londoners are met would require at least three more Earths. Today, at least 600 million city dwellers in the developing world do not have adequate shelter and 1.1 billion choke on unhealthy air. Polluted air in 36 Indian cities killed some 52,000 people in 1995, a 28 percent increase from the early 1990s. China reported at least 3 million deaths from toxic urban air between 1994 and 1996. Rapid urbanization in the twentieth century has magnified the environmental impact of cities. In 1900, only 160 million people, one tenth of the world’s population, were urbanites. By 2006, in contrast, half the world (3.2 billion people) will live in urban areas—a 20-fold increase in numbers. Because of inadequate systems and poor planning, cities are disproportionately driving global warming, deforestation, and increasing water scarcity. Changes in six areas are needed to make cities better for people and the planet:
One of the guiding principles will be to reform urban systems so that they mimic the metabolism of nature. Rather than devouring water, food, energy, and processed goods, and then belching out the remains as pollutants, the city could align its consumption with realistic needs, produce more of its own food and energy, and put much more of its waste to use. Some Examples where cities are proving to be more nimble than nations at using planning and fiscal reform to put these ideas into action: There is an increasing belief that the original approach to environmental impacts and their mitigation, characterized by centralized "command-and-control" regulation targeted at emissions and existing waste sites, is far too limited to support the achievement of a sustainable cities. As Cities move into the 21st Century the need to reduce environmental impacts, control costs, risks and liabilities are of paramount importance. Society is faced with environmental and economic issues and problems that will have profound effects upon survival, quality of life and Sustainable Development. To answer these problems and provide solutions a new, integrated and holistic paradigm is required. To this end the IETC "Cities as Sustainable Ecosystems" (CASE) Thematic Programme:
This goal cannot be reached without developing a more sophisticated coherent intellectual framework. This framework should support the development of the urban management and planning theories, methodologies required by the "new" urban decision and policy makers and technical experts so that they can develop and implement environmentally preferable processes, operations and technologies. Moreover, there is clearly a necessary role for universities at all levels in supporting basic research in this area, particularly in developing the field of ecology, and encouraging the development and diffusion of the resulting knowledge and technologies. |
