Global Urbanization's Threat to the Global Environment

Walsh summarizes the findings, and recommendations, of a new paper published in the Proceedings of the National Academy of Sciences that outlines the dramatic increase in urban populations and urban land expected globally by 2030, and the potential impact on climate change and biodiversity. In the developed world, increased urbanization can bring environmental benefits such as reduced commutes and reduced household energy use.

However, urbanization in the developing world brings its own set of environmental challenges. As Walsh notes, "in developing nations, the move from rural areas to cities often leads to an accompanying increase in income - and that increase in income leads to an increase in the consumption of food and energy, which in turns produces an uptick in carbon emissions."

Furthermore, as the PNAS paper illustrates, "[t]hose areas of Asia, Africa and parts of South America that will see urban territory grow most rapidly tend to overlap with biodiversity hotspots, concentrations of exotic plants and animals. Humans are the ultimate invasive species - when they move into new territory, they often displace the wildlife that was already living there...And as land is cleared for those new cities - especially in the densely forested tropics - carbon will be released into the atmosphere as well."

"If we do it the right way, we can mitigate urbanization's impacts on the environment," concludes Walsh, echoing the findings reported by Karen Seto, a professor of the urban environment at Yale and the lead author of the PNAS paper.

"There is an enormous opportunity here, and a lot of pressure and responsibility to think about how we urbanize," says Seto. "The one thing that's clear is that we can't build cities the way we have over the last couple of hundred years. The scale of this transition won't allow that."