We’ve covered a wide variety of urban agriculture projects in the past – the rooftop farmBrooklyn Grange, the Battery Conservancy’s new turkey-shaped farm, and futuristic vertical farms, to name a few. Our view of them has generally been positive, but perhaps urban farms deserve a second look. Edward L. Glaeser, PhD, a professor of economics at Harvard University recently put forth his radical view that urban farms reduce metropolitan density levels, and thus do more harm to the environment than good. But does his argument really hold water?

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Glaeser’s main point is that allocating metropolitan land to agriculture results in lower urban density levels and longer commutes. If America replaced just 7.9 percent of its whopping 1 billion acres of crop and pastureland withurban farms, then metropolitan area densities would be cut in half.

As he rightly points out, lower density living is associated with higher energy use and thus morecarbon dioxide emissions. His source, the National Highway Travel Survey, affirms that when urban density drops 50%, households buy over 100 gallons of gas more per year.

The increased gas consumption from moving this relatively small amount of agricultural farmland into cities would generate an extra 1.77 tons of carbon dioxide per household per year.

Perhaps this is balanced by a reduction infood miles? Not so. A 2008 study at Carnegie Mellon concluded that food delivery is responsible for only .4 tons of carbon dioxide emissions per houshold per year. While this is a sizable amount, it is clearly offset by the emissions Glaeser says result from creating urban agricultural spaces.

In sum, his argument is that “Shipping food is just far less energy intensive than moving people.” But isn’t the real debate whether we even have to move city people out in order to move farms in?

Via Boston Globe

Lead Image: The Boston Globe/istockphoto/Heather Hopp-Bruce