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A new study from the University of Surrey, UK, and the University of Aberdeen, Scotland, has revealed that vertical farming could significantly benefit the environment while meeting the growing demand for fresh produce.

The research – which focused on a vertical lettuce farm in the UK – indicates that this farming method can produce lettuce with a carbon footprint comparable to traditional field cultivation, while using 28 times less land.

The study suggests that transitioning all UK lettuce production to vertical farms could save approximately 8,000 hectares of agricultural land, a crucial finding as the country grapples with land scarcity and the need for sustainable food production methods.

Zoe M Harris, co-author and senior lecturer at Surrey’s Centre for Environment and Sustainability, said: “Our findings show that vertical farms can help reduce the climate impact of farming, especially if their electricity comes from renewable sources”.

Moving on up

The research team conducted a comprehensive life cycle assessment of a commercial vertical farm, examining its environmental impacts from the delivery of inputs to the farm, through cultivation and harvesting, to the delivery of lettuce to its point of use in the restaurant market.

The results revealed that the farm produced 740g of CO2 per kilogram of lettuce, which is on par with traditional farming methods. However, the vertical farm's ability to operate in urban settings significantly reduces transportation emissions, further enhancing its sustainability profile.

In the study, researchers found that electricity usage constituted nearly 40% of the total climate change impact of the vertical farm. This underscores the importance of energy sources; when powered by renewable energy, the carbon footprint diminishes significantly.

For instance, if the vertical farm were to use the current UK electricity average grid mix, the climate impact would increase approximately six-fold.

Michael Gargaro, a researcher involved in the study, pointed out that the materials used in vertical farming also play a critical role in its environmental impact. Notably, jute plugs used for seed germination accounted for 18% of the farm's overall climate change impact.

Gargaro suggested that exploring alternative materials such as coconut fibre or perlite could enhance the sustainability of vertical farms. “Using another material could make a vertical farm even more sustainable. Future research should consider alternatives like coconut fibre, hemp, or perlite,” he noted.

Farms of the future

Vertical farms use advanced technologies to grow crops in controlled environments, employing methods such as hydroponics, where plants are nourished with nutrient-rich water instead of soil.

This innovation not only conserves land and water but also allows for year-round crop production, addressing food security challenges exacerbated by climate change and urbanisation.

The study’s authors also examined other environmental impacts, such as water use and pollution. Vertical farming systems can use up to 90% less water than conventional farming methods due to closed-loop recycling systems.

The research team highlighted that while vertical farming presents a lower overall climate change impact, it still has areas for improvement, particularly in reducing the environmental burden associated with waste management.

In terms of waste management, the study evaluated the impacts of various disposal methods for non-recyclable waste generated by the vertical farm. Incineration, anaerobic digestion and industrial composting were considered, with findings indicating that incineration had a relatively low climate change impact compared to the other methods.

However, the potential for energy recovery and the production of compost from anaerobic digestion and composting present attractive options for enhancing the sustainability of vertical farming.

As the global population is expected to reach nearly 11 billion by 2100, the urgency for sustainable agricultural solutions is paramount. The UK currently imports a significant portion of its vegetables, relying on foreign sources that contribute to higher transportation emissions.

By adopting vertical farming practices, the UK could bolster its local food production, reduce reliance on imports, and ensure fresher produce for consumers.

A promising practice

The study's findings come at a pivotal time as food and beverage manufacturers look to adapt to changing consumer preferences and regulatory pressures. Vertical farming presents a promising avenue for reducing environmental impacts while ensuring a steady supply of fresh produce.

The ability to grow crops closer to urban centres not only minimises transportation emissions but also addresses the increasing consumer demand for locally sourced products.

Harris concluded: “Our study is an important first step towards demonstrating that vertical farming can be greener than previously thought, despite having a limited data range available. The insights gained from this research could inspire further exploration into the potential of vertical farming to transform the food sector.”