From"Containment Paradigm" to "Making Room Paradigm”
Shlomo Angel.2012. Planet of Cities, Cambridge, Massachusetts: Lincoln Institute of Land Policy.
Source: http://www.lincolninst.edu/pubs/2094_Planet-of-Cities
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Nearly 4,000 cities on our planet today have populations of 100,000 people or more. We know their names, locations, and approximate populations from maps and other data sources, but there is little comparable knowledge about all these cities, and none that can be described as rigorously scientific. Planet of Cities together with its companion volume, Atlas of Urban Expansion , contributes to developing a science of cities based on studying all these cities together—not in the abstract, but with a view to preparing them for their coming expansion.
The book puts into question the main tenets of the familiar Containment Paradigm, also known as smart growth, urban growth management, or compact city, that is designed to contain boundless urban expansion, typically decried as sprawl. It examines this paradigm in a broader global perspective and shows it to be deficient and practically useless in addressing the central questions now facing expanding cities outside the United States and Europe.
In its place Shlomo Angel proposes to revive an alternative Making Room Paradigm that seeks to come to terms with the expected expansion of cities, particularly in the rapidly urbanizing countries in Asia and Africa, and to make the minimally necessary preparations for such expansion instead of seeking to contain it. This paradigm is predicated on four propositions:
1.The Inevitable Expansion Proposition: The expansion of cities that urban population growth entails cannot be contained. Instead we must make adequate room to accommodate it.
2. The Sustainable Densities Proposition: City densities must remain within a sustainable range. If density is too low, it must be allowed to increase, and if it is too high, it must be allowed to decline.
3. The Decent Housing Proposition:Strict containment of urban expansion destroys the homes of the poor and puts new housing out of reach for most people. Decent housing for all can be ensured only if urban land is in ample supply.
4. The Public Works Proposition: As cities expand, the necessary land for public streets, public infrastructure networks, and public open spaces must be secured in advance of development.
The first part of the book explores planetary urbanization in a historical and geographical perspective, to establish a global perspective for the study of cities. It confirms that we are in the midst of an urbanization project that started in earnest at the beginning of the nineteenth century, has now reached its peak with half the world population residing in urban areas, and will come to a close, possibly by the end of this century, when most people who want to live in cities will have moved there. This realization lends urgency to the call for preparing for urban expansion now, when the urbanization project is still in full swing, rather than later, when it would be too late to make a difference.
The history of urbanization can be divided into three main periods. The first period started with the earliest cities that were founded at the advent of agriculture and the domestication of plants and animals circa 10,000 BC, and it continued until about 1800. The second period began around 1800, when urban growth rates began to accelerate, and continued until 2010, when 50 percent of the world’s population lived in cities and urban population growth rates were already declining in all world regions.
The second part of the book seeks to deepen our understanding and thus lessen our fear of urban expansion by providing detailed quantitative answers to seven sets of questions regarding the dimensions and attributes of urban expansion:
1. What are the extents of urban areas everywhere and how fast are they expanding over time?
Worldwide, urban land cover occupied 0.47 percent of the total land area of countries in the year 2000, ranging from 0.62 percent of the land area of all developed countries, but only 0.37 percent of the land area of developing countries.
2. How dense are urban areas and how are urban densities changing over time?
Density decline is both a long-term historical phenomenon and a global phenomenon.
Cities in countries with higher incomes had lower densities. A doubling of income per capita was associated with a 25 ± 2 percent decline in average density.
3. How centralized are the residences and workplaces in cities and do they tend to disperse to the periphery over time?
Three transformations can be identified in the spatial structure of cities during the past two centuries. The first transformation, from the walking city to the monocentric city, involved the introduction of reliable public transportation, primarily in the form of omnibuses, horsecars, electric trolleys, commuter rail lines, and subways, that gradually enlarged the commuting range beyond walking distance. A third transformation in the spatial structure to a polycentric city occurs when workplaces are distributed throughout the metropolitan area, drawing their workers from the entire metropolitan labor markets.
4. How fragmented are the built-up areas of cities and how are levels of fragmentation changing over time?
5. How compact are the shapes of urban footprints and how are their levels of compactness changing over time?
6. How much land would urban areas require in future decades?
A global map of projected urban land cover as a share of total land area in all countries for 2030, assuming a 1 percent annual density decline。In general, the larger the area of the country, the smaller is the share of its land in urban use. The Russian Federation, for example, will have only 0.2
percent of its land area in urban use by 2030; China, 1.3 percent; the United States, 2.4
percent; Canada, 0.2 percent; Brazil, 1 percent; Australia, 0.3 percent; Argentina, 0.3
percent; and India, 3.0 percent.
7. How much cultivated land will be consumed by expanding urban areas?
The ratio between urban land cover and the cultivated land area varied widely among different countries.
Five countries had more land in urban use than arable land: Singapore,Bahrain, Kuwait, Djibouti, and Qatar.
Three countries had more land in urban use than half the arable land cover: Puerto Rico, Iceland, and Belgium.
In 12 countries, urban land cover comprised 20 to 50 percent of arable land cover, among them the Netherlands, Japan, and the United Kingdom.
In 14 countries, urban land cover comprised 10 to 20 percent of arable land cover, among them the Republic of Korea, Venezuela, and Germany.
In 29 additional countries, urban land cover comprised 5 to 10 percent of arable land cover, among them Egypt, the United States, and Brazil.
In 45 more countries, urban land cover comprised 2 to 5 percent of arable land cover, among them Iran, Argentina, China, and the Russian Federation.
In 35 more countries, urban land cover comprised 1 to 2 percent of arable land cover, among them India and Canada.
The 12 remaining countries had urban land cover that comprised less than 1 percant off arable land cover, among them Tanzania and Afghanistan.
By answering these questions and exploring their implications for action, this book provides the conceptual framework, basic empirical data, and practical agenda necessary for the minimal yet meaningful management of the urban expansion process.