Climate change is accelerating agricultural land degradation, driving innovation in food production. Vertical farming (VF) has emerged as a climate-resilient solution, offering higher yields and lower water use. However, a recent University of Surrey study reveals that while vertical farms boost lettuce productivity, they have a higher carbon footprint than field-grown lettuce. This raises critical questions for the United Kingdom (UK) about balancing environmental responsibility and food security in adapting to future agricultural challenges.1,2
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The Emission Problem
The global population is projected to increase by two billion by 2050, reaching 9.7 billion, creating greater demand for food. Food systems and supply chains currently contribute 26 % of global emissions, threatening the Paris Agreement’s 1.5 °C goal.
Meeting future needs will require 56 % more food than in 2010, highlighting the urgent need to transform production systems and reduce agricultural emissions through sustainable innovations.1
The Need for Novel Approaches
The UK’s agricultural industry contributed £146.7 billion (6.5 %) to national gross value in 2022, with 70 % of UK land used for farming. Around 85 % of this area supports animal production, making the UK largely self-sufficient in meat, cereals, and oilseeds. Yet, the country still imports 42 % of its food, and this trend is rising.
While food security remains stable due to diverse sourcing, climate change, Brexit and global conflicts have disrupted production and prices. Events like the 2008 food price spike and the 2018 heatwave highlight the UK’s vulnerability to such pressures.1
The UK’s climate limits the cultivation of many imported crops, making seasonality and climate change major factors affecting yields. Domestic production of fresh fruit and vegetables (FFV) peaks during the summer months, while crops such as lettuce are primarily imported in winter, about 95% of which comes from Spain.
FFV has the largest trade deficit, with domestic production down 11.9 % since 1990. Spain supplies about 25 % of all vegetables and nearly 80 % of imported lettuce. This dependency makes UK food security vulnerable, as Spain faces worsening water scarcity primarily due to agriculture, threatening the reliability of these critical food imports.1
The Vertical Farming Approach
VF, a form of controlled environment agriculture, is an innovative alternative to traditional farming. It reduces dependence on imports and mitigates climate-related risks.
As technology-driven crop production systems, they optimize lighting, water, and space to create suitable growing conditions free from external influences such as pests and climate.
VF maximizes land use through vertical stacking, increasing yields per land area and reducing land requirements. Yet, its high energy demands make it costly and carbon-intensive without clean energy sources.
As the UK faces limited land, a variable climate, and heavy reliance on imported fresh produce, VF could enhance food security and resilience to global disruptions. VF is currently used for leafy greens and salad crops, capitalizing on efficient stacked production to boost domestic supply.1-3
Studying VF Sustainability
A paper recently published in Food and Energy Security performed the first comprehensive comparison of soil emissions from field farming with lettuce grown in a UK commercial vertical farm.
Using a cradle-to-store approach, researchers studied two UK lettuce farms, including one on peat-based soil and one on mineral soil, and a farm in Spain, which collectively supply the majority of the UK’s lettuce. They then compared them with the vertical lettuce farm.
The objective was to comprehend the differences in impact from VF cultivation in the UK and field cultivation in Spain and the UK, and to evaluate the sustainability of VF systems.1,2
This study expanded on the authors' earlier research on the environmental impacts of UK-based vertical lettuce farming, providing a direct comparison with the impacts of traditional production and supply chains.4 It assessed the whole system impacts of UK lettuce production and distribution using primary data from two UK farms, secondary data on Spanish field lettuce, and primary data from a UK-based VF.
An attributional life cycle assessment (LCA) studied impacts per kilogram of crop. Field lettuce cultivation impacts were calculated by incorporating emissions from agricultural processes like planting, watering, soil manipulation, chemical applications, and tillage, modeled using soil-geochemistry models for a more realistic assessment of field farming.1
The UK-based vertical farm uses a hydroponic system with four growing tiers over 150?m², cultivating loose-leaf lettuce.
Field farms grow iceberg lettuce that is comparable due to similar growth time, size, and nutritional value.
Vertical farm produce is not washed before delivery, and transportation impacts were calculated using current distribution distances to supermarkets, providing a realistic assessment of the supply chain and production impact.
Environmental LCA evaluated the impacts of products and services across multiple ecological impact categories, following International Organization for Standardization (ISO) 14040 and 14044 standards.
The study used the DeNitrification-DeComposition (DNDC) model to estimate soil emissions from field farms. This process-based tool simulates complex agroecosystem interactions and reliably predicts site-scale greenhouse gas fluxes under varied conditions.1
Significance of the Study
The study found that the vertical farm had higher emissions across all impact categories except water use.
When powered by renewable energy, greenhouse gas emissions by vertical farms were still higher but closer to those of UK field farms, at 0.93?kg CO2?eq/kg lettuce for the vertical farm compared with 0.58?kg CO2?eq/kg for UK field farms.
The major environmental hotspots for lettuce production were energy use, choice of substrate, and soil emissions.
VF achieved substantially higher yields per area with 97.3?kg/m² yield versus 3.3?kg/m² for field farms, offering significant land-sparing potential.
Water use in vertical farms was approximately eight times lower than in Spanish field farms, at 0.9?m³/kg versus up to 7.3?m³/kg. Despite these efficiencies, greenhouse gas emissions remained higher due to the energy demands of vertical systems and the use of jute fiber plugs to support plants.
Substituting jute with alternative materials such as coconut coir could reduce the land footprint of vertical farms by over 95 %, indicating opportunities to lower environmental costs.1,2
Could Vertical Farms Be the Future of Farming?
Vertical farms delivered over 20 times the yield of field farms and used significantly less water, but high energy-related emissions remained challenging.
While not yet the most sustainable lettuce production approach, advances in materials and energy could make VF vital for UK food security amid climate change and water scarcity in supplier regions such as Spain.
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References and Further Reading
- Gargaro, M., Hastings, A., Murphy, R. J., & Harris, Z. M. (2025). A Comparative LCA of Field Grown Lettuce Versus Vertically Farmed Lettuce. Food and Energy Security, 14(4), e70117. DOI: 10.1002/fes3.70117, https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.70117
- Can vertical farms really feed the UK sustainably? New study weighs climate costs and benefits [Online] Available at https://www.surrey.ac.uk/news/can-vertical-farms-really-feed-uk-sustainably-new-study-weighs-climate-costs-and-benefits (Accessed on 27 October 2025)
- Gargaro, M., Murphy, R. J., & Harris, Z. M. (2023). Let-Us Investigate; A Meta-Analysis of Influencing Factors on Lettuce Crop Yields within Controlled-Environment Agriculture Systems. Plants, 12(14), 2623. DOI: 10.3390/plants12142623, https://www.mdpi.com/2223-7747/12/14/2623
- Gargaro, M., Hastings, A., Murphy, R. J., & Harris, Z. M. (2024). A cradle-to-customer life cycle assessment case study of UK vertical farming. Journal of Cleaner Production, 470, 143324. DOI: 10.1016/j.jclepro.2024.143324, https://www.sciencedirect.com/science/article/pii/S0959652624027732
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