The Ecologist

Inspecting a tomato at the wonderful Evergreen Brick Works' greenhouse in Toronto. Photo: Joseph Morris via Flickr.

Inspecting a tomato at the wonderful Evergreen Brick Works' greenhouse in Toronto. Photo: Joseph Morris via Flickr.

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Vertical farming - viable agriculture or urban pipedream?

Matt Bevington

27th October 2014

If you don't want industrial agriculture ravaging the world to feed cities nutrient-deprived, genetically modified, chemical-drenched pap, here's an alternative, writes Matt Bevington: let cities grow their own fresh produce on 'vertical farms' in disused industrial buildings, restoring sustainability and accountability to the food chain.

The diminished risk of weather and pest damage, along with consistent crops and multiple yields, make this method of agriculture a reliable and profitable investment.

Agriculture as we know it is changing. Traditional, land-based methods have proven to be catastrophic when undertaken unsustainably.

With world population rapidly increasing, agricultural practices must be adapted to meet the ecological challenges of food production.

Agriculture occupies around 50% of the world's habitable land, consumes about 70% of the planet's accessible fresh water, and accounts for 14% of global greenhouse gas emissions (IPCC, 2007).

These are the headline figures but land-based agricultural praxis also cause persistent damage to habitats, water systems, wildlife, and soil composition.

The global land crisis

By 2050, WWF predicts that "a further 120 million hectares of natural habitats will be converted to farmland" to meet the rising demand, an area approximately the size of South Africa. Clearly, this expansion is unsustainable in the long-term, particularly as intensive agriculture can cause irreversible damage.

Each year 12 million hectares of land is lost due to agricultural practices resulting in desertification, a loss of farmland and pasture just less than the size of England. Where intensive farming of monocultures occurs, land and habitats are often devastated then abandoned.

In the UK, the Government-organised Green Food Project online forum concluded that "The food system would not be able to meet the challenge [...] over the next 30 to 40 years in its current form."

Producing more food with less resources, while lessening the impact on the environment, may seem counter-intuitive - even impossible. But vertical farming is an increasingly viable part of the solution to the ecological concerns of land-based agriculture.

Farming without land

Vertical farming is what it suggests - instead of farming horizontally, occupying vast areas of land, vertical farms comprise multi-storey, hi-tech greenhouses that can be installed in urban buildings. They utilise floor-to-ceiling space, use artificial LED light, and soil-free irrigation systems to produce multiple crop-yields each year.

While there are no standardised costs for these developments, the increasing number of investments highlighted here reflect the viability of indoor and vertical farming as a profitable business model as well as an ecological solution.

Thanet Earth, an indoor farm based in Kent (UK), has been growing hydroponically since 2008 and now accounts for 15% of the UK's salad crop production. They produce vegetables all year round where their competitors are restricted to a nine-month season.

The diminished risk of weather and pest damage, along with consistent crops and multiple yields, make this method of agriculture a reliable and profitable investment.

Dickson Despommier, Professor of Microbiology and Public Health in Environmental Health Sciences at Columbia University, is a dedicated promoter of vertical farming - and has encountered plenty of challenges.

"City capitals couldn't care less about climate change", he says. "They care a lot about sea level rises, especially in New York City, but they don't connect the dots. They're sort of on board but not for ecological considerations. They're on board for economic considerations."

A report conducted in 2008 concluded that vertical farming was "realizable and profitable. The investment return is comparable to stock market averages." The advances that will be outlined in this article highlight further efficiencies and cost-saving technologies that have improved the economic viability of vertical farming since the report concluded.

Whilst the ecological argument is well founded, vertical farming had been a difficult concept to scale-up, primarily due to high energy costs. However, advances in the efficiency of LED lighting have significantly reduced energy requirements.

"Phillips Lighting Company has come up with a 68% efficient LED light for growing food", Despommier explains. "That just happened within the last year. That has lowered the amount of money that anybody's going to have to spend on energy."

More efficient LED lighting emits only the light spectra that plants can use, produces very little heat so growers can better control the indoor climate, and can be placed much closer to crops than conventional lighting which allows systems to be stacked much closer together, utilising indoor space.

Differing systems

The development of aeroponic growing systems has further increased the efficiency of indoor farming. Roots are nourished in a nutrient mist rather than being submerged in solution.

Where hydroponic systems use 70% less water than land-based agriculture, aeroponic systems use 70% less than hydroponics. Even the cloth medium in which crops are grown can be recycled.

Land-based agriculture requires crops to be washed, creating a damp environment in which microbial life flourishes and reduces shelf-life. Aeroponics is more efficient in harvesting with no required washing that extends the shelf-life of products by up to twice as long.

Aquaponic systems offer a symbiotic, 'closed-loop' system of agriculture. Methods vary, but the basic principle is that bacteria are introduced into the base of fish tanks where it processes fish-waste.

Bacteria convert waste into nitrogen which fertilises the plants' roots which are submerged in the water that then filter the water for the fish. It is said to have "90% less water use than conventional agriculture", and facilitates the growth of crops and fish simultaneously.

Chicken coops can even be incorporated indoors where the exchange of heat, carbon dioxide and oxygen between crops and animals is mutually beneficial.

Vertical farming in practice

Technological advances have resulted in an ever-increasing and diverse range of vertical and indoor farming applications throughout the world.

"Japan has actually embraced this", says Dr. Despommier. The Fukushima disaster means that Japan requires a reliable and uncontaminated food production chain, with much of their agricultural land and fisheries having been destroyed.

"They have a small indoor growing industry already, called Plant Factories", Dr. Despommier continues, "A lot of examples involve grocery stores where the consumer can go into a store, put a plastic bag over a green item, cut it off, and take it home. It's only occurred in the last five years."

City dwellers benefit from fresh, organic produce grown nearby, putting them in close contact with the process of food production. There is even the opportunity for human waste to be processed into fertilisers and fuel, giving local authorities a source of income from selling sewage.

In Tokyo, the Pasona O2 Urban Farm is one of the world's first Eco-Offices, where, astonishingly, a hydroponic rice paddy occupies the basement of the new office block. The building exemplifies how to integrate the workspace with food production, and how to transform urban constructions into multi-functional buildings.

It is foreseeable that food production could be integrated into architecture in the same way as renewable energies.

Regeneration potential

Vertical farms can also regenerate derelict sites. In the Wythenshawe area of Manchester (UK), the Alpha Farm group are converting a derelict office building into a vertical farm. Regeneration limits the environmental costs of demolishing abandoned buildings and reconstructing on the site.

"I see a huge interest in municipalities to take the marginal, functional buildings, or non-functional buildings - these huge warehouses that are three or four storeys, tall and empty - and repurposing them", says Dr. Despommier,

Although rural land may be cheaper to purchase, it still involves the environmental costs of construction, the further appropriation of rural habitat, and significantly higher costs (both financial and environmental) of transportation and refrigeration.

The Scottish Derelict and Vacant Land Survey 2013 reports that almost 1,200 hectares of derelict land exists in Glasgow City alone, with many of these sites including building remains.

No such survey exists for the rest of the UK, but other post-industrial cities almost certainly contain substantial numbers of derelict buildings, like the Alpha Farm site in Manchester.

The Greater London Authority (GLA) owns more than 500 hectares of assets described as either 'subject to disposal', or of 'limited marketability' - indicating there is no shortage of available but undesirable buildings within urban areas that could potentially be repurposed.

The snowball is rolling ....

Dominant land-based agricultural methods cannot sustain the world population beyond the medium term without decimating habitat and exacerbating climate change. Vertical farming and the technologies associated with it are a viable, and increasingly affordable, part of the solution.

The benefits exceed beyond easing the burden on our ecological systems (vital as that is), and can actually provide employment opportunities, urban regeneration, and increased self-reliance.

As Dr. Despommier says, "I hope it will snowball. It's a pretty slow-growing snowball but I think it's crawling forward."

The innovations that have occurred so far prove him right. Agriculture is changing. The sooner the vertical farming revolution is embraced, the sooner we can all benefit from a more sustainable food system.



Matthew Bevington is an English student at Ruskin College, Oxford, and contributor to the Young Greens Blog. He has written about social justice, sustainability, and independent music.  



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