What Makes Some Cities Greener Than Others
This week I’ve been looking at green cities. Today I turn my attention to the economic, demographic, and other factors associated with cities and metros that have lower levels of carbon emissions.
Martin Prosperity Institute colleagues José Lobo, Charlotta Mellander, Kevin Stolarick, and I took a simple, straightforward statistical look at several things research and common sense suggest should be associated with higher and lower levels of carbon emissions. We measure emissions three ways, as a function of population (per capita), workforce (per worker), and economic output (per economic output). All the caveats regarding correlation not being causation apply. However, our findings underscore the fact that carbon emissions are linked as much to the way we live as how we produce and manufacture things.
One of the most surprising concerns manufacturing. Intuitively, you’d think that carbon emissions must be a function of the intensity of industrial manufacturing activity. When the subject is pollution, smoke belching factories are among the very first things that come to mind. But surprisingly, when we looked at the correlations between the metro share of manufacturing industry and all three measures of carbon emissions, we found no statistical relationship. Manufacturing plants have been under competitive pressure to eliminate waste and become more efficient for decades. A large body of studies charts the transition of manufacturing from old-line to leaner, more agile production models that reduce or eliminate defects, inventory, and waste. Industry has become cleaner.
That said, the broader structure of our industrial economy remains a real concern. Emissions, according to our analysis, are higher in metros with broader blue-collar economic structures (measured as the share of workers in construction and transport as well as production jobs). The share of workers in these kinds of jobs is positively correlated to all three measures of emissions.
This is not as big a puzzle as it might seem. Manufacturing represents only a fraction of overall economic activity (accounting roughly 6 percent of all American jobs); a much larger percentage of workers are in construction, transportation, materials moving, and related blue-collar work. While manufacturing itself is leaner and cleaner, the crux of the problem lies in the structure and development pattern of metros.
Emissions are higher in suburban style metros, our analysis shows. All three measures of emissions are higher in metros where more people own single-family homes. Conversely, the level of carbon emissions is negatively correlated with the share of renters in a metro, according to our analysis.
Cars are huge emitters of carbon dioxide, so it stands to reason that car-dependent metros would emit more. Car commuting is significant culprit in emissions across metros. The share of people who drive to work is positively correlated to all three measures of emissions, while the share of people who commute on transit and by bike are both negatively associated with all three emission metrics.
Bigger metros emit less, as my previous post showed. Metros with over 1.5 million people emit 3.77 tons of CO2 per person, compared to 6.74 tons of CO2 for those with less than 500,000 according to an MPI analysis. Emissions are negatively correlated to both population size and density, according to our analysis. Bigger cities and denser, more compact living patterns offer a double benefit: They not only stimulate innovation and leverage productivity, but also use less energy and generate fewer emissions per person.
Lower carbon emissions are linked to more knowledge-based, creative economies. The touchstones of such economies are higher levels of human capital (college grads), larger concentrations of high-tech industry, and greater levels of creative class workforces. All three are correlated with lower levels of emissions according to our analysis. Less emissions and a cleaner environment translates into a better quality of life which provides an additional edge in attracting talent and business.
Not surprisingly, residents of greener, lower emitting metros report higher levels of happiness. This shift is bound up with the deeper transformation of our economy and way of life - from an older industrial economy based on the exploitation of nature and physical labor to a more knowledge-based economy. New management systems began to see defects and inventory and ultimately emissions as costs to be eliminated. Waste became a costly enemy.
Our built environment and development patterns are just beginning to catch up. A growing number of cities and metros, especially those with more knowledge-based and talent-driven economies, place a premium on being clean and green as key elements of their quality of life and ability to attract talent. Bigger, denser metros which are less car-dependent generate greater energy efficiency and lower levels of pollution as well as higher levels of productivity and innovation.
Lasting prosperity turns on changing the way we live as well as the way we work - ensuring that our cities and metros, as well as our industries, are as clean and creative as possible.