Urban systems extract and import resources from across the world. Whether used in factories, automobiles, or households, these materials and energy resources are transformed into primary products and waste by-products by human use. Traditionally, urban systems have simply released these by-products into the local environment. Increasingly systems have been established to distribute these by-products across the globe, be it through exporting toxic wastes or using tall smokestacks. To protect ecosystems from the stresses of these accumulated wastes and pollutants, urban systems must be redesigned to recycle these by-products into other human and natural processes.
This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities. Agenda 21 recommends undertaking an extensive review of options and techniques for reuse and recycling all forms of municipal solid waste.
A number of public/private partnerships have been developed to address this issue, such as the Duales system in Germany, the Packaging covenant in the Netherlands, and the Ecoemballages system in France. Countries have promoted the extended producer responsibility aiming at transferring the costs of waste management to those who are conceiving the products that are a source of waste.
Policies for reuse and recycling should be made an integral component of national and local waste management programmes.