Sustainable Cities

A sustainable city is one that while providing a high quality of life to a diversified and plural society in the present, establishes the mechanisms necessary to ensure suitable economic and social growth in the long term while maintaining the natural resources of the environment. This will allow future generations of citizens to satisfy their needs on the same terms.

Initially, local governments were considered, from the economic and political points of view, as the most ill suited to resolve major and expensive environmental and social problems. However, in the agreements reached at the United Nations Conference on Environment and Development (the Earth Summit) held in Rio de Janeiro in 1992, it was established that many of the problems and solutions being addressed by Agenda 21, have their roots in local activities. Thus, the participation and cooperation of local authorities would be a determining factor in meeting such objectives. In this regard, it was affirmed that local authorities should maintain and promote economic, social, and environmental infrastructure; inspect urban planning projects; develop and implement local environmental policies and laws, and assist other supramunicipal administrations in implementing other environmental policies. As the administration closest to the people, they have to foment citizenship education to promote sustainable development.

The European Conference on Sustainable Cities and Towns, held in Aalborg, Denmark, in 1994 and organized by the International Council of Local Environmental Initiatives (ICLEI), approved the Aalborg Charter. This establishes that the objective of European sustainable cities is to achieve social justice, sustainable economies, and environmental sustainability.

According to the Charter, social justice will necessarily have to be based on economic sustainability and equity, which require environmental sustainability. Socially, cities should create a cooperative environment where unemployment, deprivation, and underachievement are absent and where economic development is compatible with respect for social rights. This will promote an environment where social integration—that is, the compatible cohabitation of racially, culturally, and socially diverse groups—is a reality and where, at the same time, the quality of life for all segments of the population has improved.

Environmentally, cities should use resources ethically, which means that they should minimize their consumption of resource inputs from outside the community and minimize the production of waste outputs. They must also create a society based on renewable energy, complete cycling of resources, no use or release of toxins, [Page 2747]and development as the restoration and enhancement of the environment's and economy's capacity to support life.

Environmental sustainability requires the maintenance of natural capital, which means that the consumption of renewable resources should not exceed the capacity of natural systems to replace them and that the speed at which we consume nonrenewable resources should not surpass the rhythm of substitution of lasting renewable resources. Environmental sustainability also means that the speed at which pollutants are emitted should not exceed the capability of the resources to absorb and process them.