Dr. Dickson Despommier has an unsettling message for farmers — in 50 years, he says, "soil-based agriculture will no longer be sustainable."
Despommier, a professor of environmental health at Columbia University in New York, supports his grim prognosis for dirt farming with a litany of woes for farmers of the future, among them: climate change, drought, too little farmland, too many people, and too much pollution.
"Right now farming uses 20 percent of all of our energy," said Despommier. "That figure is from the Department of Energy. And farming is the most polluting activity on earth, the USDA says that."
Climate change, predicts Despommier, is just part of the problem. Looking at current weather extremes, he sites massive floods, protracted droughts, class 4-5 hurricanes, and severe monsoons, as destroying millions of tons of valuable crops each year.
And then there is population growth. On his Web site The Vertical Farm Project www.verticalfarm.com, Despommier writes: "Applying the most conservative estimates to current demographic trends, the human population will increase by about 3 billion people during the [next 50 years]. An estimated 109 hectares of new land (about 20 percent more land than is represented by the country of Brazil) will be needed to grow enough food to feed them, if traditional farming practices continue as they are practiced today."
Assuming we will continue to farm in soil, (Despommier does not share this assumption), statistics like those Despommier cites underscore the precarious task of preserving farmland, especially considering the farmland we’ll need in the future. In the United States alone, according to the American Farmland Trust, the U.S. loses two acres of farmland every minute of every day. In five years, 1992-97, the U.S. lost 6 million acres — a portion of land the size of Maryland.
How are we going to feed ourselves in the future?
Despommier calls into question all sorts of variables we take for granted now — that it will be cost effective for food to travel great distances to get to us, that our climate will be hospitable for growing crops, that we’ll have reliable watersheds. Those givens are going to change, he believes. But the good news is that we don’t have to keep farming like we’ve been doing. We can adapt and overcome our environment just like our ancestors did before us.
"Farming is an unnatural behavior"
We didn’t always farm. Despommier points out that our ancestors were hunters and gathers, not farmers. Humans have adapted technology to feed themselves for thousands of years.
"Farming enslaves us to plants. We’re wedded to the farm and can’t leave, but imagine a system whereby you can control the climate."
Despommier promotes a version of Controlled Environment Agriculture (CEA), which enables a grower to manipulate a crop’s environment to the desired conditions, by regulating temperature, humidity, pH, and nutrients indoors. These technologies are currently used in hydroponic and aeroponic growing operations.
Despommier calls his idea "vertical farming." He’s gathering initiatives to build the first vertical farm — essentially high-tech hydroponic greenhouses stacked floor upon floor in an urban setting. The idea has sparked the imagination of several architects (see accompanying pictures of prototypes) and urban planners from around the world.
"You can’t control anything outside," said Despommier. Farmers are subject to a host of ills farming outdoors — bad weather, floods, insects.
Why not do it all inside? argues Despommier.
"Farming is an unnatural behavior."
Isn’t there something strange about growing food without soil?
Despommier doesn’t think so.
"We’re advancing our culture. All we’re doing is taking the advances of plant science to determine how to grow good, healthy plants."
If we don’t pursue these technologies, Despommier argues, and figure out a way to build productive, local foodsheds in the future, "the world will become a much more unpleasant place in which to live."
"I’m not against local farms or farming, but there are a billion people starving to death. Vertical farming could make a tremendous difference."
The argument for vertical farming
Vertical farms would use hydroponic technology, which has amazing potential: year-round crop production, no polluting run off, huge yields compared to conventional agriculture, crop variability, water savings, to name just a few.
Environmental friendliness is a strong argument in favor of CEA. "An organic farmer takes a big loss on yields," said Despommier. "Conventional farming gets better yields, but uses herbicides and pesticides."
Because the indoor environment is completely controlled in hydroponics, with screened filtration systems, and no soil, there is no need for herbicides or pesticides. "Hydroponics is beyond organic."
But, enthuses Despommier, the most exciting thing about CEA is the variability and the yields. Hydroponics has nearly 20 times the yield rate of conventional agriculture (depending on the crop, strawberries are up to 30 times). And all the variables can be controlled. "Imagine a world in which there is no more weather-related crop failure."
"With indoor plants, our crop loss is 2 percent," said Despommier. "Corn? You can grow 18 ears in 3 feet. You can harvest it every 5 to 8 weeks by idealizing the conditions."
And with indoor agriculture, crops can grow all year. Because the system recycles the water the plants grow in, hydroponics uses 70 percent less water than conventional farming. This sustainability means vertical farms could be ideal for growing in desert areas. Vertical farms, claims Despommier, "could be built in any climate from the desert to the North Pole."
Despommier goes so far as to boast: "Vertical farming can replace Nebraska with five buildings."
And without the environmental degradation of Nebraska’s soil and watersheds.
Despommier vows: "There will be vertical farms in the near future."
Not so fast, says Cornell professor
Dr. Louis Albright, director of CEA research at Cornell University isn’t so sure. While he applauds the idea of building hydroponic greenhouses close to urban centers, and is a leading researcher in the field of hydroponics, he foresees some technological hurdles before the world builds its first vertical farm.
Albright’s biggest concern about vertical farms is that they are vertical. "My number one concern is light. Plants need light." With floors above and floors below, the verticality is going to shade the plants. "This means that you’d have to use supplemental light and that triples the electrical costs."
On the issue of light, Despommier responded that designers could solve that problem by creating a curved, transparent building that is not as tall as it is long. "Perhaps five stories high but long. Parabolic mirrors stationed in back of the building could bring sunlight into the ‘dark’ side of the vertical farm. In the Middle East, long narrow vertical farm might be up to a mile in length to capture sunlight."
Albright also questions the economic feasibility of growing most crops, like grains for instance. "There’s no point in growing grains hydroponically, because you can store them." Hydroponics, in his opinion works best with things that are highly perishable, like lettuce and tomatoes.
According to Albright, only the technology for hydroponics is feasible now.
"We’re not too successful with aeroponics" — a system in which plants grow in a medium that is constantly misted. "One brief power outage can kill your crop," said Albright. "And it’s hard to get mist to move around."
Albright concedes that with enough research and development funding, CEA technology is full of potential.
"If you’re NASA, you can grow anything."
Unfortunately, for most growers, they don’t have NASA budgets.
On a small scale, however, Albright thinks hydroponics is an option for independent farmers.
"That is the direction we’re trying to move." An acre or so, size greenhouse is "well suited for the family farm. It’s efficient agriculture."
Albright sees a model where these sorts of small, hydroponic farms could be vertically integrated by a larger company "for stability and negotiating power against utility charges."
It’s exciting technology in terms of its minimal environmental impact. "One of the goals of CEA is to avoid dumping nutrients — there is no environmental discharge," said Albright. But he confesses that the energy costs are great.
"Greenhouses take energy to heat, so until the technology improves, there is not an advantage in terms of cost," said Albright.
Could the energy costs of CEA ever be recouped by using renewable energy sources?
Despommier envisions heating vertical farms with biofuels and methane digesters, or wind and solar energy. Albright is also intrigued by the possibilities of CEAs going greener.
"We can do other things to reduce energy, if we control CO2 and light, we can reduce the need for light by half!" said Albright, referring to new advances in plant science.
He’s hopeful for the future of the technology.
"There’s lots of interest in in now. People are looking at it seriously."
But Albright doesn’t see an end to soil-based agriculture. "Drive across the Midwest. There’s lots of land. It’s good land. I can’t imagine a situation so desperate that we’d grow everything indoors."
Is anyone doing this?
Away from Despommier’s drawing boards and the research facilities of Cornell, entrepreneurs are making a go of growing hydroponically. In the United States, the largest commercial hydroponics farm in the world is Eurofresh Farms in Willcox, Arizona, a greenhouse compound of 318 acres under glass. There they grow cluster tomatoes, cucumbers, and peppers grown in a rock (or mineral) wool medium.
There’s some discussion if Eurofresh tomatoes can be considered organic, although they are grown without pesticides or herbicides. USDA certification requires soil to obtain organic certification.
Another cutting edge CEA is The Eden Project in England, which includes the world’s largest greenhouse. The project is a collection of "biomes" or artificial ecosystems, each with its own separate "climate," which houses plants from all around the world.
What inspires Despommier about The Eden Project that could be transferable to vertical farms is the space-age polymers that the biomes are constructed from — ethylene tetrafluoroethylene, ETFE, a kind of plastic, designed to have high corrosion resistance and strength over a wide temperature range. "It’s miracle stuff," enthused Despommier.
What makes it ideal for greenhouses (or biomes, if you’re so inclined) is that it captures the maximum amount of sunlight. Compared to glass, ETFE film is 1 percent the weight, transmits more light and costs 24 percent to 70 percent less to install. It’s also resilient (able to bear 400 times its own weight, self-cleaning (due to its nonstick surface) and recyclable.
"High-tech greenhouses exist," said Despommier pointing to these successful CEA examples. "Vertical farms are just stacking them, and integrating the systems. We know how to do this. We’re going to do it."
What about taste?
The space age of hydroponic technology is all very fine and good, but what about the taste of hydroponic vegetables? Isn’t dirt primal? Doesn’t it give our food some essential flavor that water-soluble nutrient solution can’t?
No, says Despommier and gives a recitation of the chemical compounds that go into plant physiology. "What makes a plant taste good? Flavanoids. Too much water dilutes flavanoids, too little concentrates the sugars. With vertical farming you can control these variables."
He cites the tomatoes from Eurofresh Farms which won "America’s Best Tasting Tomato" by the American Culinary Institute.
Albright agrees that you can adapt plant conditions for different flavors. "The major difference is that plants (grown hydroponically) are more tender, because they are less stressed. Nutritionally they are the same."
In a world where a billion people are starving, should we care about the nuances of tomato flavor? If it is a choice between CEA farming and no farming some day, what then? Will we be that desperate in 50 years?
Despommier doesn’t know, but he’s pretty certain we can’t keep farming the way we’ve been, or we’ll destroy our planet.
"The Bible says we are the stewards of the earth," said Despommier. "That means we have to manage it. Take care of it. Don’t destroy it."
"If we are not good stewards of the earth, we will destroy ourselves."
Source: Lancaster Farming
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