Atlas of Urban Expansion

     At a time when the world’s cities are bursting with massive increases in population, visiting fellow Shlomo “Solly” Angel continues to lay out a vision for better planning, with the publicatiion this week of the Atlas of Urban Expansion, followed by the companion volume Planet of Cities  later this summer. 
     Half of the world’s total population already lives in cities, and that urban population is expected to nearly double in the next 40 years, from 3.5 to 6.2 billion people -- nearly all in developing countries, where burgeoning megacities will likely more than triple their developed land areas by 2050.
     Increased global awareness is needed to better understand and plan for this massive expansion of cities in developing countries, Angel says. Local and national governments, civic institutions, international organizations, and concerned citizens must make minimum adequate preparations. For example, he says, it is vital that cities acquire the rights-of-way for arterial roads that can carry public transport and trunk infrastructure and protect selected open spaces from encroachment in advance of the coming expansion.
     The main objective of the Atlas of Urban Expansion is to increase understanding and help residents, policy makers, and researchers around the world come to terms with the expected global urban expansion in the coming decades. The call to action is urgent, as the urbanization process now underway will be largely completed by the end of the 21^st century.
     “Most people who desire to live in urban areas will already be in them by 2100, but by that time it will be too late to act,” Angel says. “If the land required for public works or public open spaces is not protected from encroachment before it is developed, it will be next to impossible to ensure the orderly development of cities to make them more efficient, more equitable, and more sustainable.”
     The Atlas of Urban Expansion is part of a long-term research project that includes a series of related publications and online resources including three working papers, the Policy Focus Report Making Room for a Planet of Cities; and the online version of the Atlas.
     The Atlas in book form introduces the project and presents two sets of full-color maps and a set of raw data tables. The first contains pairs of urban land cover maps from circa 1990 and 2000 for a global sample of 120 cities. The second includes composite maps of a global representative sample of 30 cities, showing the historical expansion of their urbanized areas from 1800 to 2000. In both sections, the maps are paired with numerical and graphical data, making it possible to compare cities in terms of their metric values on key attributes of urban expansion. The third section contains four extensive tables of urban, national, and regional data for each of the 120 cities.
     The book Planet of Cities, to be published in late August, recommends making adequate room for increased urban population growth, rather than emphasizing containment; adjusting densities within a sustainable range; providing an ample supply of urban land for decent housing; and securing land necessary for public streets, public infrastructure networks, and public open spaces well in advance of development.  Angel will present the research at the World Urban Forum organized by UN-Habitat in Naples, Italy, in September.