What is it?
Vertical farms are facilities that grow crops indoors, with multiple layers of plants stacked on top of each other, using artificial lights, large heating and cooling systems, humidity controls, water pumps, and complex building automation systems. In principle, vertical farms can dramatically shrink the land “footprint” of agriculture, and this could help reduce the need for agricultural land. Moreover, by growing crops closer to urban centers, vertical farms could potentially reduce “food miles” and the emissions related to food transport.
Does it work?
The technology of growing some kinds of crops – especially greens and herbs – in indoor facilities is well developed, but there is no evidence to show that doing so can reduce GHG emissions compared to growing the same food on traditional farms. Theoretically, vertical farms could reduce emissions associated with agricultural land expansion and food transportation. However, the operation and construction of vertical farms require enormous amounts of energy and materials, all of which cause significant emissions. Vertical farms require artificial lighting (even with efficient LEDs, this is a considerable energy cost), heating, cooling, humidity control, air circulation, and water pumping – all of which require energy. Vertical farms could be powered by renewable sources; however, this is an inefficient method for reducing GHG emissions compared to using that renewable energy to replace fossil-fuel-powered electricity generation. Growing food closer to urban centers also does not meaningfully reduce emissions because emissions from “food miles” are only a small fraction of the life cycle emissions for most farmed foods. Recent research has found that the carbon footprint of lettuce grown in vertical farms can be 5.6 to 16.7 times greater than that of lettuce grown with traditional methods.
Why are we excited?
While vertical farms are not an effective strategy for reducing emissions, they may have some value for climate resilience and adaptation. Vertical farms offer a protected environment for crop growth and well-managed water use, and they can potentially shield plants from pests, diseases, and natural disasters. Moreover, the controlled environment can be adjusted to adapt to changing climate conditions, helping ensure continuous production and lowering the risks of crop loss.
Why are we concerned?
Vertical farms use enormous amounts of energy and material to grow a limited array of food, all at significant cost. That energy and material have a significant carbon emissions cost, no matter how efficient the technology becomes. On the whole, vertical farms appear to emit far more GHGs than traditional farms do. Moreover, vertical farms are expensive to build and operate, and are unlikely to play a major role in the world’s food system. At present, they are mainly used to grow high-priced greens, vegetables, herbs, and cannabis, which do not address the tremendous pressure points in the global food system to feed the world sustainably. There are also concerns about the future of the vertical farming business. While early efforts were funded by venture capital, vertical farming has struggled to become profitable, putting its future in doubt.