In the future, 'visiting a farm' could mean something completely different. (Getty: LouisHiemstra)
It's brunch time in the not-too-distant future. You're in your favorite cafe and you have a craving for pancakes.
You know they're delicious because you order them all the time: fluffy and light with a slightly carroty taste.
Hardly a health food, but at least they're easy on the environment – they're made with organic eggs and 100 per cent locally-sourced bacteria.
The bioreactor that produces the flour is only a block away.
Like many people, you're worried about the carbon footprint, so it's good to know.
The coffee is good too – from a boutique plantation in an old converted office block just down the road.
It's expensive, but it's worth paying a little more to make sure you eat and drink.
Your friend orders the pork and fennel sausages with a side salad – from the rooftop farm above the cafe.
She often feels guilty about the amount of meat she consumes. But at least the pig she's eating was raised on micro-algae, not soybean. So, a small chunk of the Amazon is still standing because of the trees in that area.
Eating pancakes (CEA).
And CEA, some agricultural research argue, which is the best way of reducing the environmental destruction associated with modern farming, which is both land and resource intensive.
The veggie patch goes high-tech
CEA represents a small but growing dimension of agriculture.
It's attracting huge investment, particularly in the United States
Vertical farms look like a cross between a factory and a laboratory.
Plants are grown on trays, often stacked up to 30 tiers high.
For vertical farms, like this one in New Jersey, the crucial ingredient is the artificial lighting. (Getty: Angela Weiss / AFP)
Everything about the indoor environment is governed by sensors and automation, but the crucial ingredient is the artificial lighting.
"All the vertical farms operating today are using a type of lighting called LEDs, which stands for light emitting diode," says Jeffrey Landau, a director of business development at Agritecture, an urban agriculture consultancy.
"Different types of crops prefer different types of lighting. So, your leafy greens, your vegetative crops prefer light towards the blue side of the spectrum.
"Whereas your fruiting and flowering crops, they will want something more along the red spectrum of lighting."
Each variety of plants has their own tailored lighting recipe, allowing them to photosynthesise for much longer periods of the day – up to 18 hours at a time.
In practical terms, that means more crop yields.
The fields of Bowery Farm, located just outside New York City, go upwards. (Getty: Don Emmert / AFP)
The major players, to date, have concentrated on producing perishable goods such as salad vegetables – crops that traditionally require large amounts of water.
But vertical farming expert Paul Gauthier believes even staples like potatoes and wheat could eventually be grown indoors.
"Everything is possible. I don't think there is anything in the vertical farm that we can't grow," he says.
"I was growing coffee trees inside a vertical farm.
"What kind of economics are behind it."
Dr Gauthier, who is now working for the New Jersey-based company Bowery Farming, admits both the capital and energy costs involved in vertical farming are "absolutely huge".
But that needs to be put in context, he argues, because significant government subsidies have long been provided to traditional farming operations.
People in glass houses
Others aren't so convinced.
Bend Puri sees the Silicon Valley-inspired approach adopted by companies like Bowery as unnecessarily high-tech.
"It has certainly attracted a tonne of investment, media attention, consumer interest, there's no doubt about it," he says.
"I still think the business models will require a path to profitability before it can start to attract more mainstream financing."
Mr Puri, the CEO and co-founder of Gotham Greens, operates five rooftop urban greenhouse facilities in New York and Chicago.
His approach to controlled environmental agriculture is to recast the classic Dutch greenhouse of an earlier age, but with 21st century modifications.
"These are glass and steel structures controlled by computers that are able to monitor climate, 365 days a year, 24 hours a day, and make smart adjustments, data-driven adjustments, in order to maximize crop productivity, efficiency, reduce production losses, "Mr Puri says.
"They combine a lot of advanced horticultural and engineering techniques that proponents of vertical farming espouse and promote."
And they also have the potential to achieve exponential crop yields.
"One can still get 50 times the productivity on certain types of crops. But one relies is primarily on natural sunlight which is a free natural resource," Mr Puri says.
Next year, Gotham Greens is a 2,800-square-meter facility just outside Denver, Colorado, as part of a $ 70 million capital expansion plan.
Some Some of these greenhouses are the backyard hoop houses, but rather sophisticated climate-controlled buildings, Mr Mr Puri says,
And they can get even bigger.
A French company is currently constructing a roof-top greenhouse in the center of Paris that will cover some 14,000 square meters when completed.
Like Bowery Farms, Gotham Greens sells itself on growing pesticides.
"Urban farming is about bringing issues closer to large population centers," says Mr Puri.
"And telling the story of how agriculture is an important role in a more sustainable future."
The substitution game
For Cambridge University's Asaf Tzachor, the solution lies in environmental degradation.
The future of food that he envisages is busy fermenting away in a bio-reactor in Iceland.
The facility is run by a company called Algaennovation, which has been experimenting with the development of a new kind of animal food supplement made from microalgae.
Dr Tzachor estimates up to 85 per cent of the soybean produced globally.
Soybean farming in South America is identified by environmental agencies as a major cause of deforestation.
So, the idea is to simply substitute the microalgae for soy.
Pedigree plantation in Amazon rainforest, like this one near Santarem, relies on deforestation and environmental degradation. (Getty: Ricardo Beliel / Brazil Photos / LightRocket)
"Microalgae are very interesting. They are marine organisms, which means that they don't need freshwater, unlike soybean," says Dr. Tzachor.
"And we don't have to cultivate them on terrestrial areas, so we can grow them within facilities, and these facilities can also be closed."
The savings on water alone would be significant, says Dr Tzachor.
He says experiments at Algaennovation's facility have so far been able to achieve between 200 and 250 times more biomass per liter of water than soybean farming.
The next stage of development is demonstrating that microalgae production can be done on a mass scale.
The Algaennovation plant in Iceland has been experimenting with microalgae. (Supplied by Algaennovation)
A similar approach is being made by researchers in Finland, but their focus is on producing a supplement for human food rather than stock feed.
Pasi Vainikka, Solar Foods, says that his company has used a bio-reactor to produce an edible flour made from fermented bacteria.
"We have a fermenter, but we don't use yeast. We use a specific microbe that doesn't eat sugar," he says.
"So instead of sugar we introduce carbon dioxide and hydrogen, and these microbe uses for energy and carbon instead of sugars to grow.
"Then we take the liquid out of the fermenter when the microbes grow and multiply and you end up with a dry powder."
The flour, called Solein, has a 65 per cent protein content, says Dr Vainikka, and can be used as a substitute for wheat flour or soy in everything from bread to protein drinks.
"The organism has carotenoids. When you taste it raw it has a bit of an umami (savory) taste," he says.
"When you add it to pancakes, for example, it tastes as if it would have egg, and also a bit of carrot taste."
"The production cost, according to our estimations, is around $ US5 per kilogram."
But that cost, says Dr Vainikka, could be expected to decrease as production begins to scale.
"We are about 10 times more environmentally friendly than plants and about 100 times better than animal-based proteins," he says.
"If we want to make a fundamentally more sustainable food system for the growing population, we need to disconnect from agriculture, which usually means irrigation, use of pesticides and a lot of land use.
"So, when we disconnect from everything that has to do with these processes, the environmental benefits are huge."
Despite the promise offered by controlled environmental agriculture, Mr Puri cautions against the world's growing food demand issues.
"I think solutions are going to be unique and they are unique to their own geographical, economic, social and cultural contexts," he says.
"I think there are many different ways to farm sustainably and responsibly.
"Indoor farming techniques can play a significant role for certain types of crops, high-value crops, crops that use a lot of water, crops that often have to be shipped in refrigerated trains, planes or trucks over great distances."
But the challenge is great. The United Nations estimates 9.7 billion by 2050.
That's another 2 billion mouths to feed.