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Urban agglomerations and their resource uses are becoming the dominant feature of the human presence on earth, profoundly changing humanity’s relationship to its host planet and its ecosystems. The cities of the 21 century are where human destiny will be played out and where the future of the biosphere will be determined. | Thematic Paper 2 Urban Agriculture and Sustainable Cities URBAN AGRICULTURE AND SUSTAINABLE CITIES Tjeerd Deelstra and Herbert Girardet 1. Introduction At the end of the 20th century humanity is involved in an unprecedented experiment we are turning ourselves into an urban species. Large cities not villages and towns are becoming our main habitat. Urban growth is changing the face of the earth and the condition of humanity. In one century global urban populations have expanded from 15 to 50 of the total which itself has gone up from 1.5 to nearly 6 billion. The size of modern cities in terms of numbers as well as physical scale is unprecedented. In 1800 there was only one city with a million people London. By 1990 the world s 100 largest cities accommodated 540 million people and 220 million people lived in the 20 largest cities megacities of over 10 million people some extending to hundreds of thousands of hectares. Urban agglomerations and their resource uses are becoming the dominant feature of the human presence on earth profoundly changing humanity s relationship to its host planet and its ecosystems. The cities of the 21st century are where human destiny will be played out and where the future of the biosphere will be determined. It is unlikely that the planet will be able to accommodate an urbanised humanity that continues to draw upon resources from ever more distant hinterlands or which uses the biosphere the oceans and the atmosphere as a sink for its wastes at the current accelerating rates. The challenge faced is whether cities can transform themselves into self-regulating sustainable systems - not only in their internal functioning but also in their relationships to the outside world. Is it possible to make a world of cities viable in the long term -socially economically as well as environmentally The answer to this question is critical to the future well-being of the planet as well as of humanity. There can be no sustainable world without sustainable
