Designers love to praise vertical farms’ sustainability and combating climate change is a huge part of that, but there’s a lot more nuance than most other articles go into.
Sustainability is not just a measure of how much water your system recycles or how many solar panels it uses, and these resources are not the only things that affect climate change.
Not only that, but also there isn’t just one type of vertical farm: there are farmscrapers, farms that float, rooftop gardens, converted warehouses, and tricked-out greenhouses just to name a few.
The kicker? Each model is going to have entirely different measures of sustainability, especially when it comes to a carbon footprint.
Let’s take the obvious example. The original farmscraper envisioned by Dickson Despommier, whose name everyone should know, is a 30-story building bearing tremendous amounts of water and carbon-rich plant weight. What is such a structure’s carbon footprint?
Looking at one emblematic skyscraper (1 Penn Plaza for the purposes of this exercise), we can calculate the estimated square footage of such a farmscraper.* Once we have an estimated square footage, we can use a carbon footprint calculator to run the numbers. In New York City, the carbon footprint of one of Despommier’s vertical farms is 63,360 metric tons of CO2 just in construction.** This means that for every floor built, 2,112 tons of CO2 are released into the atmosphere. To put that into perspective, the average American produced 19.8 tonnes from 1980-2006 (much higher than the average Chinese citizen who only produced 4.6 tonnes).
In dense cities like these where much of the available land has already been developed, you also have to take into account knocking existing structures over and shipping the materials away.
Plus, these figures don’t even consider the various inputs for the different high-tech components that get so many people (us included!) excited about vertical farming.
On the other end of the spectrum, we can take a look at The Plant in Chicago. We, just like probably anyone else writing about this stuff, are huge fans of The Plant. First and foremost, they proposed to release a replicable and quantifiable business plan for everyone else to study their system.
More importantly for this piece, The Plant has a significantly smaller carbon footprint. Housed in an abandoned meat packing facility, The Plant up-cycled itself into existence. Construction utilized existing materials and structures instead of knocking down and building from scratch with imported materials.
It get’s even better. Data from a study by the National Trust for Historic Preservation claims that to “retrofit an existing building [is] to make it 30 percent more efficient” than even building a new one using cutting edge sustainable tech.
If we use the same resource to calculate The Plant’s carbon footprint, we arrive at 2,468 metric tonnes of carbon emitted, and that’s if The Plant was even built from scratch. That’s a huge difference to the farmscraper above, but there are some important trade-offs. A building situated in the heart of NYC is going to be able to produce more food and service more people than a relatively small warehouse in an industrial district. More importantly, there is no reason a skyscraper can’t be upcycled sustainably or even built out of wood (slashing its carbon footprint by 75%) in order to get the best of both worlds. Even still, the true costs of a project start to come out when you think along these lines and it get’s harder to ignore externalities when you think beyond capital investment.
Inside The Plant: Arugula
Below is an excerpt from this article talking about the National Trust for Historic Preservation’s study and the data that they found comparing new construction to retrofitting buildings.
The most interesting data lie in how new buildings compare to existing ones if we don’t even bother to retrofit them. This chart from the report shows how much time it would take for a new building that’s 30 percent more efficient to overcome – through all that efficiency – the impact of its construction (much of which lies in the use of all that new material).
Something else to consider: bringing agriculture indoors, especially soil-less agriculture, may actually be worse for the climate in some respects than holistic and environmentally friendly outdoor versions. Though there isn’t a lot of research or data on this now, and the Urban Vertical Project doesn’t subscribe to this, consider the below graphic from Center for Food Safety about how important soil is as a carbon sink.
What are we trying to say?
Sustainable solutions are much more nuanced and not as ubiquitous as simplifying the issue would make them appear. As vertical farming and building integrated agriculture continue to grow, marketers have to be careful with their blanket sustainability claims and dreams of saving the planet with one simple switch in agriculture have to be kept in check.
By the way…
We’ve had a lot of growth on this site, almost as soon as we started posting. We’re glad you guys love it and we want to thank you. So to do it, the Urban Vertical Project is developing a killer presentation template for an amazing vertical farm funding pitch and we’re giving it away for free for a limited time! It’s based off a real pitch we saw that got funded and we know you’re going to love it. To hear about it before anyone else, sign up for our newsletter below (just your first name and email, and we really, really won’t send you too much stuff).
Preservation Green Lab. (2011). The Greenest Building : Quantifying the Environmental Value of Building Reuse. Report by the National Trust For Historic Preservation.
*1 Penn Plaza is a 57-story, 2.4 M square foot building. By making the assumption that a farmscraper would have a similar story/sq foot ratio and using the construction carbon calculator found here, we arrived at the 1.2 M square footage estimate.
**It is beyond this article to evaluate this calculator, but here is the resource we used: http://buildcarbonneutral.org/