“What if every city can grow 10% of its food indoors?”. This was the question that was first posed to us by Dickson Despommier in 2010 through his book The Vertical Farm: Feeding the World in the 21st Century.
The argument from a climate change perspective was that by reducing the need for soil-based commercial agriculture practices, we would then lower the carbon emissions produced from land tillage, water and chemical (synthetic mineral salts, pesticides, herbicides, etc) usage, on-farm waste, and supply chain logistics.
Despite the rise of Controlled Environment Agriculture (CEA), often touted as the support needed for soil-base agriculture to co-exist (ideally through the likes of regenerative agriculture, supply chain overhauls, etc.), the agriculture industry is still taking a hit. As the recent IPCC report indicates, the frequency and intensity of droughts will likely occur up to 4.1 times every ten years compared to 1.7 times at present. Although sustainability has always been at the forefront of CEA, there are still gaps. For example, “The HVAC ducts and fans used for CEA operations pump in CO2 to keep levels at about 1,000 parts per million, about two and a half times the typical outdoor level. Trays of lettuce and kale soak up light from LED tubes, which stay on for 16 to 17 hours per day and use up to 70% of the 600 to 700 kilowatt-hours consumed per day.” (VegetaFarm, Tokyo).
Source: IPCC
"The HVAC ducts and fans used for CEA operations pump in CO2 to keep levels at about 1,000 parts per million, about two and a half times the typical outdoor level. Trays of lettuce and kale soak up light from LED tubes, which stay on for 16 to 17 hours per day and use up to 70% of the 600 to 700 kilowatt-hours consumed per day.” (VegetaFarm, Tokyo). |
Small Changes, Long Term Carbon Footprint Reductions
We believe that there’s a simple but relatively overlooked way for CEA to squeeze out those final bits of carbon emissions: agriculture inputs.
Every single agriculture input that goes into the growth of crops has a carbon footprint. But is it positive, neutral, or negative? To assess this, a few things need to be identified: the product’s raw material, where it’s sourced from, and how it can be put back into the food system post-usage (this is the most challenging bit). We need to differentiate between the main categories of agricultural inputs which are consumable inputs (eg: nutrients/fertilizers, seeds, etc) and supplies.
For consumable inputs, a carbon emissions reduction opportunity is through fertilizers/nutrients. Where soil-based agriculture will gravitate towards compost, CEA operations need to find an equivalent. Take for example Away We Grow©. A one-acre indoor farm eliminates 1.62 metric tons of CO2e from the atmosphere annually and removes 18.75 pounds of CO2e that would have been released from food waste sent to landfills per gallon of Away We Grow© used.
As for supplies, grow media is an area to explore. At the moment, the industry predominantly uses rockwool, followed by peat or coco coir. All of them have their pros and cons. But in terms of fighting climate change, all of them are carbon positive. For example, rockwool is an inorganic material that is hard to degrade, the leftover rockwool waste is often stockpiled or landfilled, resulting in further environmental externalities. As for peat, the removal of it from the ecosystem reduces the carbon sequestration capabilities of natural peatland which is 0.37 Gt of CO2/year. In fact, peatland stores more carbon than all other vegetation types in the world combined (2018). By harvesting and using this peat, we’re removing the exact thing that we’re hoping to sequester and eliminate from our atmosphere, and that is carbon.
"As for supplies, grow media is an area to explore. At the moment, the industry predominantly uses rockwool, followed by peat or coco coir. All of them have their pros and cons. But in terms of fighting climate change, all of them are carbon positive." |
In summary, the two points above aren’t related to energy usage, which is currently the industry’s largest CO2e contributor. However, a little goes a long way, and this method requires the CEA industry to take a hard look at its consumable agriculture inputs and supplies, which could make a monumental difference if everyone commits to this change.
by Riyana Razalee