Farming in the Sky
Agriculture is broken. Traditional techniques use too much energy and produce too little food for our growing planet. One fix: skyscrapers filled with robotically tended hydroponic crops and lab-grown meat
By 2025, the world’s population will swell from 6.6 billion to 8 billion people. Climate simulations predict sustained drought for the American Midwest and giant swathes of farmland in Africa and Asia. Is mathematician Thomas Malthus’s 200-year-old prediction, that human growth will one day outpace agriculture, finally coming to pass? Advances in farming technology have kept us fed so far, but the planet’s resources are tapped.
The choice is clear—rethink how we grow food, or starve. Environmental scientist Dickson Despommier of Columbia University and other scientists propose a radical solution: Transplant farms into city skyscrapers. These towers would use soil-free hydroponic farming to slash demand for energy (they’ll be powered by a process that converts sewage into electricity) while producing more food. Farming skyward would also free up farmland for trees, which would help remove carbon dioxide from the atmosphere. Even better, vertical farms would grow food near where it would be eaten, thus cutting not only the cost but the emissions of transportation. If you include emissions from the oil burned to cultivate and ship crops and livestock in addition to, yes, methane from farm-animal flatulence, agriculture churns out nearly 14 percent of the world’s greenhouse-gas emissions.
You can’t buy vertically grown groceries just yet. Most urban farming efforts have been small-scale experiments run in neighborhood parks. Despommier’s vision is bigger: a $200-million, 30-story tower covering an entire city block, stuffed with enough fruit, vegetables and chickens to feed 50,000 people. “With waste in and food out, a vertical farm would be like a perpetual-motion machine that feeds a lot of people,” he says. Most of the technology already exists, he adds, and with some refining, the project could be up and running quickly if granted 0.25 percent of the subsidies paid to American farmers in the past decade—a piddling $500 million.
Despommier is advising investors in Abu Dhabi and South Korea who are considering vertical farms for new eco-cities. Seattle and Las Vegas are investigating similar, smaller concepts. Turn the page to explore the farm of the future, inspired by cutting-edge research from agricultural companies and scientists. With any luck, it will help repel the Malthusian catastrophe for another 200 years.
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Farming in the Sky a floor by floor look
This automated “conveyor belt” system, conceptualized by
OrganiTech, an Israeli company that creates automated farming systems, takes aquaponics one step further. The tank’s slow current carries floating trays of plants [1] past nutrient dispensers [2] and, by the end of the weeks-long trip, the plants are ready for harvest. Below them swim high-protein tilapia [3], whose ammonia-laden waste sinks to a gravel bed [4], where bacteria convert it to nitrogen. The system pumps this nitrogen-rich water to the plants, which consume the nitrogen and return clean water to the fish.
But not all plants respond well to hydroponic methods. Some, such as potatoes and citrus trees, need to set root in a semisolid medium, like soil or coconut fiber. The design here, by the Canadian company Omega Garden, does just that. In this Ferris-wheel-like growing system, plants grow in porous, vermiculite-stone-filled trays [1] arranged in a cylindrical cart [2] that rotates to periodically dip each row of plants in a nutrient trough [3].
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Inside the Vertical Farm
Turbines
Vertical-axis wind turbines are potentially 50 percent more efficient in low wind conditions than conventional turbines.
Elevators
Farmers load harvested plants onto a central elevator to be sold at the grocery store below.
Monitors
Ceiling-mounted systems monitor and control humidity, temperature, and nutrient distribution.
Robots
Robotic arms equipped with mechanical noses “sniff” plants and harvest them based on the presence of specific alcohols, a more precise judge of ripeness than color.
Optimal Crops
Plants don’t have millions of years to adapt to indoor hydroponic growth cycles, so botanists must select and breed the strains that perform best. Other scientists will blend specialized fertilizers for the plants so that they’ll contain micronutrients essential to the human diet, like selenium and zinc.
Security
Even a few insects or pathogens could decimate the enclosed crops, so farmers entering the building must don containment suits and pass through airlocks. Scientists will coat plants with genetically modified bacteria that glow in the presence of a threatening disease or pest, alerting farmers to an outbreak.
Meat
Raising cattle is inefficient—only 3 percent of the energy used to raise a cow ends up as protein on your plate. Instead, scientists will cultivate slabs of meat in the lab from chicken, pig or cow stem cells raised on a diet of water, glucose and natural proteins. To approximate the texture of meat, they will “exercise” the muscle with electrical pulses. The fatty texture of a porterhouse is too complex to replicate, but sausage and chicken nuggets should be routine in a decade.
Lighting
LED bulbs save energy and can be tuned to the specific wavelengths favored by each species (only red for lettuce, for example).
Chicken
Chickens require little space and yield one pound of meat per two pounds of feed—very efficient by farming standards.
Sewage
The vertical farm converts 100 tons of sewage into 19 megawatts of electricity.
Market
Neighbors purchase vertical-farm goods in the tower’s ground-floor grocery store, and electric trucks deliver food to local markets.
========================================================================To watch a the video of the structure click this
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