Vertical Farm, photo credited to Valcent via www.economist.com

It’s been days since Edward Glaeser published his urban farm-bashing piece in the Boston Globe, but I’m still annoyed. Glaeser, a professor of economics at Harvard University and director of the Rappaport Institute for Greater Boston, managed to argue against farms in a way that could extend to urban parks, gardens, zoos, swimming pools, and most sidewalks. He also ignored  some intriguing trends in making urban farming more efficient, a.k.a. the Vertical Farm.

But before I give you a view from the roof, let’s consider what’s happening on the ground. Glaeser chaired the Citizens’ Committee on Boston’s Future, a group gathered by the Boston City Council in 2010 to figure out “what Boston must do to compete to be the best city” in four quick and easy kind-of-public meetings: you can read Shirley Kressel’s sour assessment of the group, or just read the final report. You’ll find urban farms mentioned three times in 23 pages. Apparently, Glaeser is concerned that people might take them too seriously. Here’s an excerpt from his Globe piece:

“But while neighborhoods benefit from the occasional communal garden, it is a mistake to think that metropolitan areas could or should try to significantly satisfy their own food needs… Farm land within a metropolitan area decreases density levels and pushes us apart, and carbon emissions rise dramatically as density falls… Urban farms mean less people per acre which in turn means longer drives and more gasoline consumption. Shipping food is just far less energy intensive than moving people.”

Now, just for fun, I’m going to substitute the word “park” for “farm” and “plants” for “food.”

“But while neighborhoods benefit from the occasional communal garden, it is a mistake to think that metropolitan areas could or should try to significantly satisfy their own plant needs… Park land within a metropolitan area decreases density levels and pushes us apart, and carbon emissions rise dramatically as density falls…Urban parks mean less people per acre which in turn means longer drives and more gasoline consumption. Shipping plants is just far less energy intensive than moving people.”

Who needs the Emerald Necklace when you can get plants from a florist? It’s much less resource-intensive to just buy a ficus tree at a shop when you want one instead of wasting precious city space on a sycamore. Heck, they don’t even have leaves half the year.

Of course, we do have parks. Apart from the Boston Common, all of Boston’s Emerald Necklace parks were established when Massachusetts had been rapidly, rampantly deforested for timber and farm land, reaching a low of ca. 30% forest cover by 1850. We’re back up at about 60% forest now. (See this “Wildlands and Woodlands” report put out by the Harvard Forest for an interesting, slightly confusing graph of the process on page 5.) Bostonians had many reasons for putting large, wasteful fields of money-wasting green space in their cities—water treatment, religious beliefs, public health, civic pride. I talk about them in my book  Boston’s Gardens & Green Spaces.

But really, the reason we still have most of our parks—with some glaring exceptions, like Wood Island—is that people like them, and are willing to work to protect them. In Boston, we have groups like the Emerald Necklace Conservancy, the Friends of the Public Garden, Friends of Franklin Park; have you ever heard of the Friends of the Bowker Overpass? The Hynes Convention Center T-Stop Conservancy? They’re public works, too. Somehow, they don’t attract quite the same affection.

Historic postcard of sheep grazing in Franklin Park, courtesy of the Dorchester Historical Society

Nowadays, people like Boston’s farms too: Revision Houses’s farm, and the Food Project, and Allandale Farm. It may be simply a fashion, but Boston has had plenty of park fashions in the past; the preferred way to experience plants changes from generation to generation. The Public Garden was a botanical garden when it was first decoratively planted in 1837. Mount Auburn and Forest Hills Cemetery were enormously popular with 19th-century tourists who enjoyed viewing trees among the dead. In 1885, Frederick Law Olmsted convinced Bostonians that the highest and best use of Franklin Park was to graze sheep. In the 20th century, parks like Wood Island and a portion of the Riverway were paved over altogether, to construct Logan Airport in Wood Island’s case, and to make a parking lot for Sears out of the poor Riverway.

(Mind you, not everyone is keen on the idea of farms in the city. In May, some Dorchester residents objected to the “arrogant” way the city of Boston was promoting farming on four vacant lots in the neighborhood, prompting City Councillor Charles Yancey to declare “This is not a plantation.” Abutters also voiced fears of increased rodent populations. A representative from Revision House, which has been operating a small farm in Dorchester for more than 20 years, said that there weren’t any more mice than usual at Revision’s Farm.)

But even if urban-dwellers willingly waste their precious money and space on mere lettuces, is Glaeser right? Will urban food production ruin our economy, change our climate, and make our world a more miserable place to live?

The answer seems to be no, because current city set-ups and rural agriculture are already making our world a more miserable place to live. Cities save energy to be sure—it’s a lot cheaper to heat a two-bedroom apartment than a free-standing house, and walking and public transportation make a difference too. But all that carbon-saving efficiency comes at a price; American cities use vast quantities of energy and fresh water dealing with feces, urine, and food waste. (Some Kenyan city-dwellers can take advantage of Sanergy’s recycling waste into methane.) Sewage and rotting food has to go somewhere.

At the same time, rural agriculture wastes vast quantities of water. U.S. growers pour pesticides, herbicides, and fertilizers on crops to keep pests away and give them nutrients—and still lose millions of pounds of crops to floods, drought, spoilage, disease, and pests each year. Fresh water used for irrigation runs off, depleting fertilizer and leaching these chemicals into the groundwater and local rivers. The result: a dead zone of 7000 square miles in the Gulf of Mexico, and saline and heavy metal contamination of California’s Central Valley Aquifer, which is used to irrigate California’s most productive crop land. Yuck.

Gordon Graff's proposed SkyFarm, via www.verticalfarm.com

There is an alternative: vertical farms. Build a skyscraper full of crops instead of people—or better yet, build giant greenhouses on top of existing buildings—and you won’t take up any more of Glaeser’s precious productive economic land. Heck, the hydroponics firm Brightfarms is already plunking a greenhouse on top of a supermarket in Brooklyn just like Boston chefs are growing greens on their restaurant roofs and the Food Project is farming 6,000 square feet on a parking deck at Boston Medical Center.

Present-day urban farms take up far less water than rural farms. According to the Economist, in 2006-9 a hydroponic barge in New York City, growing crops without soil in nutrient-laden water, used one tenth as much fresh water as a comparable farm field—with no run-off, and no pesticides, and a potential year-round growing season.

The barge used one-tenth as much water as a comparable field farm. There was no agricultural run-off, and chemical pesticides were replaced with natural predators such as ladybirds. Operating all year round, the barge could grow 20 times more than could have been produced by a field of the same size, says Dr Caplow.

Vertical Farm diagram, via www.verticalfarm.com

In a perfect world, vertical farmers could also make use of composted food waste. They could even purify “black water” (sewage), or “gray water” left over after solids are removed from sewage.  New York City alone produces a billion gallons of gray water a day.  Instead of sending gray water it to a waste treatment plant, vertical farms using it to feed fast-growing non-edible plants like duckweed, sawgrass, and cattails (well, cattails are edible, but most people don’t know how.)  Harvest your sawgrass to make methane, and you’ve got clean water and energy!  And a rather odd view from the 45th floor. Look out your balcony at…duckweed?

Sure, vertical farms will require some investment, and hydroponics isn’t exactly the all-natural back-to-the-land experience that some city-dwellers yearn for, now that less than one percent of Americans claim to be working as farmers. But if, as Vertical Farms author Dickson Despommier states, the world population is projected to increase from 6.8 billion to 9.5 billion by 2050, we’re going to need a lot more cropland to provide calories: an area the size for Brazil. Where else are we going to find it?