Is there an optimal urbanization strategy?

Cities are going to get bigger. With more than half the world now living in urban areas, and that percentage growing steadily, that means the concrete and steel will have to stretch out into areas that are currently forest and farm and grass. But just letting that process happen without a plan is likely to be a very bad idea.

A study published in the journal Landscape and Urban Planning simulated the urbanization process in the Piedmont region of North Carolina out to 2032. The question the authors posed was, essentially, what land will suffer in favor of the ever-growing city?

“The application of conservation planning scenarios in land change modeling is often implemented by simply treating priority areas as protected, essentially removing them from eligibility for development,” the authors wrote. “However, full protection of all priority resources is highly unlikely in urbanizing areas.” By understanding what types of policies are likely to result in the best use of land, that type of failed prohibition might be avoided.

The study used a model known as FUTURES to simulate how the Piedmont area in North Carolina will urbanize in the coming years. The area, which the authors note is often overlooked in terms of natural resources as it lies between the Appalachian Mountains and the coastal plain, is “home to numerous endangered or threatened species, natural heritage areas, and exceptional aquatic resources.”

Under a “status quo” scenario where no new land use policies are implemented, developed area would increase by 229 percent from 1996 through 2032. Such a growth in city area would mean a 21 percent loss of farmland and a 14 percent loss of forest. They did find that with other policies that prioritize certain types of land and resources above others, “priority resources” could be spared while still allowing for the growth of urban areas likely to be needed.

There is not, however, a magic bullet policy to achieve such goals. Prohibiting development in sensitive and important natural areas had the ancillary effect of exporting development to other potentially sensitive spots; as the authors put it, “exclusionary policies may unintendedly encourage sprawl.” Meanwhile, a policy that would put more people in a given development area would spare forests and farmland, but would be a poor way to save “tier one” resources, or areas considered highly sensitive or of significant importance for one reason or another. Similarly, a policy of promoting “infill” (essentially putting more people where built stuff already exists) also would save some lands but hurt those high priority areas. You can’t win ’em all.

Last year, we looked at a study that predicted that the next 50 years will see a 139 percent increase in urban sprawl in the U.S. Southeast, including one enormous unbroken cityscape from Raleigh to Atlanta. That study concluded that we humans are terrible at taking our ability to predict the future and adjust accordingly, meaning the sprawl will take over everything while we sit and watch. The authors of the new study are slightly less pessimistic, though certainly tempered in their enthusiasm: “Ultimately, landscape outcomes will depend on the fine balance between population driven demand, human agency, and the ability to employ appropriate conservation planning policies,” they wrote. A failure to act on our knowledge, however, “is likely to result in irreconcilable losses.” – Dave Levitan | January 20 2015

Source: Dorning MA, Koch J, Shoemaker DA, Meentemeyer RK (2014). Simulating urbanization scenarios reveals tradeoffs between conservation planning strategies, Landscape and Urban Planning, 136 (2014) 28-39. DOI: 10.1016/j.landurbplan.2014.11.011

Image: Shutterstock, Oxygen64