Creating an Equation for Cities May Solve Ecological Conundrums

In this Generation Anthropocene podcast, scientists explore the ways urbanization might lead to a greener future

Cities can be problems and solutions for environmental sustainability. ispyfriend/iStock

There's always been a certain allure to the bright lights of the big city—the concentration of human activity can offer hopes for better economic opportunities and wide cultural experiences. Today, about half of the world population lives in cities, including around 30 recognized megacities of 10 million people or more.

As cities grow in size and number, a big question is whether they are a problem or a solution for environmental sustainability. Getting to an answer first means figuring out how cities work in a fundamental way—just as teasing out the effects of a chemical reaction requires an understanding of the basic elements involved.

That's why Luis Bettencourt of the Santa Fe Institute is using his work modeling complex systems to come up with a grand equation for cities.

"If you ask the question that way, you’re looking for a comparative perspective, a perspective that allows you to look at many different cities and extract what’s common about them," Bettencourt explains in this podcast episode from the Generation Anthropocene archives.

As Bettencourt tells podcast producer Mike Osborne, cities are essentially concentrations of social networks, which grow and evolve as new technologies come on the scene. At their core, cities solve many human problems stemming from our physical needs in combination with out desires for social interaction.

Certain types of cities also solve environmental problems, albeit in a non-intentional way. For instance, while urbanization usually leads to higher energy consumption, energy use per person can be different across cities.

"When we look at cities big and small in the same nation, we tend to see that the energy per capita in larger cities is often smaller than in smaller cities," says Bettencourt. It's a question of density—more people in a concentrated area can be more sustainable when they have access to shared resources like good public transit.

So can we make cities work for us and for the environment in a more deliberate way? Listen to the full episode to find out:

One of the environmental issues cities of the future will need to address is light pollution. Also in this episode, Stanford researcher Alexandra Peers speaks with Tyler Nordgren, a professor of physics and astronomy at the University of Redlands, about this uniquely urban problem.

Nordgren points out that the urban boom has created generations of people who may never see basic cosmic sights like the Milky Way, because the faint glow of our home galaxy is being drowned out by street lamps, office lights, car headlights and other sources of city glare.

The problem is about more than aesthetics. Nocturnal animals, like sea turtles, are being led astray by light pollution.

"Sea turtles come up on the Florida coast to lay their eggs. And when those eggs hatch, there is something hardwired into the brains of those little baby sea turtles, that they know they have to crawl to the sea in order to survive. And in their brains, finding the sea seems to be associated with following the light," he explains.

"Unfortunately, when most sea turtles hatch these days, the brightest thing in the sky is not the moon or the stars out over the sea, it’s the development, the housing development, the condominiums, the gas station in the other direction."

In addition, recent studies suggest that light pollution may be hurting human health is some unexpected ways. Listen to the full episode above to find out more. 

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