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GIS-based maps document explosive urbanisation

Washington, US

Cities in the developing world must prepare for explosive growth with realistic projections of urban land needs, generous metropolitan limits, selective protection of open space, and well-planned street grids, according to a new report published by the Lincoln Institute of Land Policy.

Making Room for a Planet of Cities, the Lincoln Institute’s latest Policy Focus Report, is an analysis of the quantitative dimensions of past, present, and future global urban land cover and suggests a new paradigm for accommodating rapid growth in cities, where over half the population of the world now resides. Lead author Shlomo Angel, a visiting fellow at the Lincoln Institute, is presenting the findings at an event hosted by Cities Alliance and the World Bank.
“This research will be indispensable to prepare for the surge of population growth expected in the developing world’s major cities,” said Gregory K. Ingram, president of the Lincoln Institute of Land Policy.

The report is based on a five-year statistical analysis of GIS-based maps from four new data sets:
•    The built-up areas of a global sample of 120 cities with 100,000 people or more, 1990 and 2000, based on satellite images;
•    Historic population density data in digital images for 20 U.S. cities, 1910-2000, based on census tracts;
•    Built-up areas of a representative global sample of 30 cities, 1800-2000, from the set of 120 cities based on historic maps; and
•    Urban land cover areas of the universe of 3,646 cities that had populations of 100,000 or more in 2000, based on satellite images.

According to the research, the world’s urban population is expected to double in 43 years, while urban land cover will double in only 19 years. The urban population in developing countries is expected to double between 2000 and 2030 while the built-up area of their cities is expected to triple. The key findings show that on average, population densities in the urban built up areas of developing countries are double those in Europe and Japan, and densities in Europe and Japan are double those of the United States, Canada, and Australia; and that on average, the annual growth rate of urban land cover was twice that of the urban population between 1990 and 2000. Most of the cities studied expanded their built-up area more than 16-fold in the twentieth century.

The research suggests that preparation for the sustainable growth of cities in rapidly urbanising countries should be grounded in four key components: the realistic projections of urban land needs; generous metropolitan limits; selective protection of open space; and an arterial grid of roads spaced one kilometer apart that can support transit.
Making Room for a Planet of Cities, by Shlomo Angel, with Jason Parent, Daniel L. Civco, and Alejandro M. Blei provides both the conceptual framework and the basic empirical data and quantitative dimensions of past, present, and future urban expansion in cities around the world that are necessary for making minimal preparations for the massive urban growth expected in the coming decades.

“Urbanisation is the defining phenomenon of this century. The impact of rapid urbanisation will be felt most acutely in developing countries,” said Abha Joshi-Ghani, manager of the Urban Development and Local Government unit at the World Bank. “For this rapid and inevitable urban expansion to lead to equitable, inclusive and green growth – we need to respond in innovative ways, embracing new paradigms.”

“This research goes to the core of one of the world’s most pressing developmental challenges: how to plan for the doubling of the world’s urban population,” said William Cobbett, manager of Cities Alliance, a global coalition of cities and their development partners housed at the World Bank. “The dominant current model is to marginalise and exclude the urban poor, and then spend two or three decades trying to fix the problem, at vast financial and human cost. The authors make a compelling case for a new paradigm that is both affordable and practical: anticipating, planning and making preparations for future urban growth. If applied in the secondary and primary cities of Africa and Asia, such an approach could transform the future of developing world cities.”

Source: PRNewswire