NEW YORK (Thomson Reuters Foundation) - Dangerously weak planning is leading to unchecked urban sprawl, leaving new city dwellers far from transportation and services, United Nations experts said.
A lack of solid urban planning affects two-thirds of the world population that will live in cities by 2050, said the head of UN-Habitat and other experts introducing a U.N. Sample of Cities, a study of 200 cities with populations of more than 100,000.
The sample is intended as a research tool tracking trends from air and water quality to commuting times, housing affordability and access to public space, they said.
So far, the sample shows an increase in average land use per capita over the last 25 years, said Joan Clos, executive director of UN-Habitat, a U.N. agency. The most recent figure is 277 square meters per capita compared with 203 meters in 1990, he said.
"What is happening ... is an increase of sprawling urbanization," Clos said on Thursday. "Informality is gaining share in the growth of cities."
A lack of urban planning carries political, social and economic risks that are "very dangerous and very imminent," he said.
"The fact that urban growth is less and less planned is a very, very worrisome situation," Clos said.
Decreasing over time, according to the sample, has been the amount of built-up areas within walking distance of a main road, meaning less accessibility to public transportation, he said.
Also it shows the size of city blocks increasing, "which is a symptom of weak planning," he said.
City planners often say smaller blocks encourage residents to walk more, creating more intersections with commercial activity and less demand for transportation.
Since 2007, more than half of the world's population lives in cities, according to UN-Habitat. By 2050, 70 percent of the world's projected population of 9 billion people will be urban dwellers, it says.
The sample of cities is intended as a tool for studying urbanization ahead of a U.N. conference on cities to be held in October in Quito, Ecuador and for implementing the U.N.'s Sustainable Development Goals adopted last fall to tackle such issues as poverty and climate change, Clos said.
Reporting by Ellen Wulfhorst, Editing by Ros Russell; Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, property rights and climate change. Visit news.trust.org