Help the environment, stay in the city

Do you really want to be good to the environment? Stay away from it. Move to high-rise apartments surrounded by plenty of concrete. Americans who settle in leafy, low-density suburbs will leave a significantly deeper carbon footprint, it turns out, than Americans who live cheek by jowl in urban towers.

Further, when environmentalists resist new construction in their dense but environmentally friendly cities, they inadvertently ensure that it will take place somewhere else--somewhere with higher carbon emissions. Much local environmentalism, in short, is bad for the environment.

Matthew Kahn, an economics professor at UCLA, and I have quantified the first paradox. We estimated the amount of carbon dioxide that an average household would emit if it settled in each of the 66 major metropolitan areas in the United States.

Then we calculated, for 48 of those areas, the difference between what that average household would emit if it settled in the central city and what it would emit in the suburbs. (The remaining 18 areas had too little data for our calculations.)

The five metropolitan areas with the lowest levels of carbon emissions are all in California: San Francisco, San Jose, San Diego, Los Angeles, and Sacramento. These areas have remarkably low levels of both home heating and electricity use.

Coastal California emits little electricity or heat primarily because of its extremely temperate climate. The great irony is that while carbon emissions would fall if more Americans moved to temperate California, California environmentalists have, for decades, been fighting to limit development in their state.

But in almost every metropolitan area, carbon emissions are significantly lower for people who live in central cities than for people who live in suburbs. New York City has the largest gap in emissions between central city and suburbs of any metropolitan area in the country--unsurprisingly, since New York’s central city is the epitome of dense urban living.

Our estimate is that an average New York City resident emits 4,462 pounds less of transportation-related carbon dioxide than an average New York suburbanite. The reductions in carbon emissions from home heating and electricity are comparably large, thanks to New York’s famously tiny apartments. Manhattan is one of the greenest places in America.

In only four cases in the entire 66-city sample were carbon emissions higher in central cities than in suburbs. In Los Angeles, central-city residents are using far more electricity than their suburban counterparts--possibly because newer, energy-efficient houses tend to be in the suburbs and because the urban core has many large homes.

In Pittsburgh, Dayton, and Detroit, central-city residents are using a lot of energy to heat their homes. Again, this reflects primarily the older stock of homes in these places: if the central cities were spawning modern, efficient apartments, they would be more energy-efficient.

The data suggest a strong general pattern: households in dense urban areas have significantly lower carbon emissions than households in the suburbs.

So California environmentalists have things exactly backward. If climate change is our major environmental challenge, the state should actively encourage new construction, rather than push it toward other areas.

It should ease restrictions in the urban cores of San Francisco, San Jose, Los Angeles, and San Diego. More building there would reduce average commute lengths and improve per-capita emissions. Higher densities could also justify more investment in new, low-emissions energy plants.

Similarly, limiting the height or growth of New York City skyscrapers incurs environmental costs. Building more apartments in Gotham will not only make the city more affordable; it will also reduce global warming.

Henry David Thoreau was wrong. Living in the country is not the right way to care for the Earth. The best thing that we can do for the planet is build more skyscrapers.

This piece originally appeared in Washington Examiner

This piece originally appeared in Washington Examiner