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Karen Seto on the Environmental Impact of Expanding Cities [Part One]
September 1, 2011 By Russell Sticklor
“When we think about the environmental impacts of rapid urbanization, we really need to unpack what we mean by ‘urbanization,’” said Karen Seto, an associate professor in Yale University’s School of Forestry and Environment Studies, in this interview with ECSP. “There is the demographic component, where more people are living in cities; there is economic urbanization, which is where livelihoods and economies are becoming more urban rather than rural; and then there is the land component – the conversion of land from agriculture and other ecosystems to become urban.”
Seto is the lead author of a new article, “A Meta-Analysis of Global Urban Land Expansion” (with Michail Fragkias, Burak Güneralp, and Michael K. Reilly), which uses satellite imagery to help document the physical expansion of urban areas in developed and developing nations between 1970 and 2000.
Over that period, the population of cities in the developing world boomed. In 1970, there were roughly the same number of city dwellers in developed nations as in developing nations. By the mid-1990s, however, urban residents of the developing world outnumbered their developed-world counterparts by a factor of two to one. Since then, the gap has continued to grow.
According to the report, urban growth sprawled to cover nearly 60,000 square kilometers of previously non-urban areas during the last three decades of the twentieth-century. One of their most interesting finds, said Seto, was that “urban expansion has been occurring in low-elevation coastal zones more than it has been elsewhere.”
“Essentially what that means is that cities are growing precisely in areas that are highly vulnerable to the impacts of climate change, like sea level rise and storm surges,” she said.
Demography and the Environment
Seto acknowledged that many of the today’s discussions surrounding urbanization focus on the negative impacts for the environment and human security – among them the “loss of agricultural land, conversion of forests, biodiversity loss, changes in hydrology, and climate effects.” Ultimately though, she said, urbanization and its attendant land-use changes shouldn’t be viewed through a black-or-white lens.
“Certainly we think about the oncoming demographic transition of something like three billion more people living in cities,” Seto said, but “that means there’s a lot of efficiency to be gained, whether it is in education, energy, sanitation, or health – urbanization allows for opportunities for really efficient use of resources.”
The real challenge to achieving environmentally sustainable urban development, said Seto, is thoughtful city planning: “How we configure ourselves has a big impact on the environment, so it is not the issue of just whether we are urbanizing – the form in which we urbanize [also] has a huge impact.”
Part two of Karen Seto’s interview is available here. The “Pop Audio” series is also available as podcasts on iTunes.
Sources: Population Reference Bureau, UNFPA.Topics: Africa, Asia, demography, environment, environmental health, Friday Podcasts, population, urbanization
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