As the world becomes increasingly urban, data and technology may allow us to add “artificial” natural capital to the planet’s “natural” capital in self-sufficient cities that “farm” zero-transport-miles sustainable food taking the light and heat they need from renewables and emitting no toxic waste. Meanwhile, traditional farming threatens the UK’s carbon reduction targets. Jon Herbert reports.

We plough the fields and scatter is becoming a very troublesome if ancient and well-tried technology. Part of the answer could lie in a new and very green concept for the built environment that might be commonplace by the mid-21st century.

A new report from the universities of Sheffield and Vermont, plus the Danish CGIAR Research Programme on Climate Change, says there is definitely something wrong down on the farm. In fact, agriculture — which releases one-third of the world’s greenhouse gases, methane and nitrous oxide — is now seen to be just as guilty a culprit of global warming as the power-generation and transport industries.

Ruminating cattle belch out methane. Researchers say that adding fertilisers to soil produces large volumes of nitrous oxide to the point where emission cuts of one gigatonne per year must be made by 2030 if binding carbon-reduction targets are to be met. To put one gigatonne of gases into context, it has been likened very approximately to the weight of all the skyscrapers on the planet put together.

The mitigating measures proposed by the world so far will only cut this figure by 21–40%, they calculate. The research team is so alarmed that it predicts the goals of the Paris climate agreement negotiated in December 2015, and ratified by 119 nations in May 2016, will not be met unless things change.

The challenge for agriculturalists is to convince farmers that it is commercially possible to lower emissions sufficiently without jeopardising their livelihoods. For example, methane inhibitors can reduce bovine flatulence by a third without depressing milk yields. Breeding programmes are producing cattle that naturally pass less methane. Similarly, selected cereal crops release less nitrous oxide as they grow. However, a more negative and very topical finding is that excessive antibiotics use with cows leads to higher methane emissions because they give bacteria that produce more gas in digested food an edge.

But another way to produce food with much lower environmental impact may soon be found in the successors to the weighty skyscrapers of today.

Vegan pie in the sky

Hydroponics is the science of growing food without soil. As schoolchildren know since Major Tim Peake joined the International Space Stations, hydroponic horticulture even works in orbit. All that is needed is water — which can be recycled — containing mineral nutrients plus energy from light that is often artificial. Plants can take sufficient energy from light to convert carbon dioxide and water into glucose during photosynthesis, the process behind all vegetation. Any essential pesticides and herbicides can be controlled and contained.

One of the main gains of hydroponics is that crop yields can be up to 10 times higher than from conventional farmlands. Coupled with a zero-transport requirement to haul food from distant fields to shops to tables, this makes hydroponics eminently suitable for “hyper-local” farming. What is more, hydroponic farming can be stacked in tiers and floors skywards — where it is said that better sunlight and clean fresh air improves yields and quality. However, if artificial lighting is used, derived from sustainable no-carbon sources, hydroponic agriculture could be taken deep underground and still be fresh and nutritious. In fact, the technology was originally developed as an underground alternative.

In the worst-case future scenario where the natural environment has been critically compromised, it might be feasible for mankind to retreat underground into sustainable subterranean cities. That is still in the realms of science fiction, and research and development (R&D) has some way to go yet before becoming desirable or practical. However, it also means that crops can be grown at night and during the winter months, greatly increasing output.

New green shoots for hydroponics

Why is hydroponics in the news? The answer is technology. The information age is suddenly making hydroponics as an industrial and commercial process much more efficient.

Fujitsu in Japan is leading the way. By analysing data from a host of low-cost sensors, it is showing how it is now possible to use cloud-based data to finely control heating, ventilation, pH levels, light intensity, humidity and other sensitive variables smartly and remotely to create optimum conditions at minimum resource costs to grow food products of exact weights and with precise nutritional values. The company says that gathered data is allowing it to improve food quality and achieve higher yields. Its aim is to make it easier and more attractive for young companies to enter a rapidly growing market. In terms of environmental impacts, there could be no extra power or transport costs if, as in Fujitsu’s case, produce is delivered immediately to adjacent hospitals, supermarkets and hotels.

China is also entering the same high-growth market, although for the time being the Chinese company, Alesca, is taking disused shipping containers and transforming them into automated hydroponic mini-farms. The company’s founder, Young Ha, says the mini-farms require no more than a two-hour labour input each week, adding that shipping containers were a deliberate choice as ideal to create optimal conditions specific to each individual crop type.

The Alesca project uses efficient LED lighting, plus automation and software tools to constantly micro-adjust growing conditions as plants mature and make different demands. More specifically, sensors monitor exact plant conditions and report how healthy they are at that point of their growth cycle. If changes are needed, the system adjusts the flow of nutrients, temperature, light levels and humidity to maintain an optimal environment at that point. The company’s aim is to eventually provide hyper-local food products for China’s densely populated urban centres.

High-rise farming

Other designers are already going much further in suggesting how sustainable cities might look. If they are right, there could be many interesting challenges ahead for architects, municipal planners, regulators, construction companies, contractors and the extended supply chain.

One US company has already designed an “urban skyfarm” for downtown Seoul in a heavily-populated area of the central business district. The design draws its morphological inspiration from the shape of giant trees. Standing on a relatively narrow street-level base and creating shade and ground-level shelter from the weather, floor after floor of tiered growth decks spread out above and head skywards.

Even though it is currently just a concept, the vertical pastures and forest would be powered entirely by wind and solar energy, absorb storm run-off, convert carbon dioxide locally into gaseous oxygen, prevent urban heat hotspots and process grey wastewater. On the outer edges, medium-sized fruit trees and large vegetables would be exposed to natural sunlight; within the tower smaller crops would receive artificial light for photosynthesis. If built, the structure would provide 44,000m² of outdoor farming deck space and 28,000m² of indoor farming room, plus 3200m² of solar panels.

The company has also developed plans for a “phototropic tower” swathed in green for lower Manhattan. Another concept is phototropic housing in San Francisco that would benefit ergonomically from maximum sunlight harvesting.

Not seeing the wood for the lack of trees

Nearer to home in the UK, trees are in trouble. Although it is calculated that 13% of the UK is currently covered by woods and forest, a considerable improvement on the nadir a century ago of 5% after the First World War, there are claims that Britain is suffering from “creeping deforestation”. The Government’s new annual target announced in the last autumn statement is to plant 11 million new trees during the lifetime of the present Parliament.

Trees are not just pretty, although the Office for National Statistics calculates that their recreational value is worth nearly £5 billion. They also have an environmental role to play as weather conditions become more extreme in reducing water flows, preventing river siltation, absorbing air pollution and sequestrating carbon. The Department for Food and Rural Affairs (Defra) is also looking at the role of trees in its natural flood resilience review.

However, a number of factors hold back tree planting programmes. A lack of data is one. A shortage of saplings is another. Diversity is a further issue. Disease is attacking specific species. The net figure could be a decline in woodland cover, even though the Forestry Commission is adamant that “a lot more trees should be planted as a climate change response”.

And now for something completely … awful

There is another natural resource that is of growing value to humans.

Hands up who likes insects? How many would eat insects? Insect revulsion is in the main a culture thing. Our six-legged friends are more than just food for thought in many parts of the world — they could be on the future menu of much of the world’s growing population. The UN estimates that 2.5 billion people eat insects every day. Cockroaches are an example of where biodiversity is bringing great benefits to mankind. Only four of the world’s 4500 different species are considered pests.

The European Food Safety Authority (EFSA) has stepped in to assess how safe it is to use insects as protein food sources for humans and animals. It concluded that risks depend on the type of husbandry being used. Large-scale farming is likely to be comparable to other animal productions systems, it says.

The UN Food and Agriculture Organisation (FAO) estimates that some 1900 animal species are eaten by people and as the world population soars, high-quality insect protein and good food conversion rates make them an important nutrition source. Further research into viruses and allergies is expected.

But now it could be your turn! In November 2015, the UK’s first insect restaurant, Grub Kitchen, opened in South Wales in association with Dung Beetles Direct, an insect research centre and tropical bug house. The truth is that entomophagy — humans eating insects — is an expanding business sector with circa 30 new firms making everything from crisps to protein shakes from their parts in the USA.

The logic is that with the global population set to swell from 7 billion to 9 billion in the next few decades, and with farmland in short supply and inefficient, ridden by toxic chemicals and thirsty for water, bugs make sense and potentially lots of money.

The truth is that we already eat crushed beetles carcases (cochineal) as food colouring, spread bee vomit on our toast (honey) and wrap moth excrement around our necks (silk). It is estimated that most of us already consume some 2lbs of insect bits every year.

Published by Croner-i on 20 June 2016