This episode is sponsored by Audible
One of the greatest constraints on human civilizations has been the need
to travel outward to new horizons to find fertile land to gather and farm from. What
if the solution is to go upward not outward?
So today we’re taking a look at vertical farming
asking what it is and what the opportunities and challenges are in developing it, and if it
can ever become practical. Now discussion of vertical farming almost always involves
discussion of other farming techniques, typically greenhouses, soilless farming,
hydroponics, aquaponics, aeroponics, and other controlled-environment agriculture
and so we will discuss those today briefly too, but vertical farming itself is the concept
of growing farms in vertical stacks, multiple levels, or of just taking far
more advantage of height in farm layout.
As an example, in a future of low gravity space
farming, up and down aren’t much harder to work with than left and right or forward and
back, whereas you usually want optimize maximum internal volume per external surface
area on space habitats, keeping them compact, so you would be a lot more likely to see farmed
volumes rather than farmed areas, so to speak.
Now the biggest hurdle of vertical
farming is cost, it's outrageously expensive to build up or even to build at
all, compared to raw cleared land. Mostly, we’ll get into current exceptions today
and expected future ones. This is also why vertical farming is almost always discussed in
tandem with controlled-environment agriculture, because while something like a greenhouse is
usually hugely more agriculturally productive than an equal area of open land, the cost to build and
maintain one is often considerably higher than an equal amount of land is. However if you’re already
building up for stacked vertical farm layers, putting a roof and sides on to control
the environment doesn’t cost much extra, but gives huge rewards, so tend
to almost always be included..
A lot of the costs for vertical and
controlled-environment agriculture are likely to go down as we improve technology, and
also proportionally down as we seek to get more food out of less land and land values rise. So
too, the cost of food traditionally – especially for citizens in an urban area - is mostly not
the cost to produce it and more the cost of transportation and storage. And especially
in the case of items prized for freshness, like herbs and some fruits and vegetables, urban
agriculture that cuts out the transportation and storage issues can get away with premium
prices more viable for vertical agriculture.
Now a lot of our examples of
controlled-environment agriculture, especially vertical farming, tend to rest their economics
on taking advantage of discounts and freebies, something like building out of discarded
shipping pallets or abandoned urban warehouses. I applaud any hobbyist or entrepreneur taking
advantage of deals or recycling that way but it does represent a false cost for upscaling
– you run out of free discards – and it makes it very tricky to really look at the future
economics of vertical farming because so many of the known examples are of that sort.
Similarly, it's not uncommon for advocates to credit big production with vertical farming in
cases where that is more from the controlled environment aspects. It's not false but it can be
a touch misleading from a future expansion point of view because any scenario in which vertical
farming has come to produce a large fraction of our food is one in which we either have
hyper-energy-abundance and/or amazing automation, or it's one in which we have already replaced
open-air farming with domes and greenhouses over it all, in which case we’re comparing
the economics and productivity of vertical farming to that, not open-air farming.
And we should probably start there, because it does show how the costs contrast. Good
agricultural land isn’t cheap, it can run several thousands dollars per acre, but that pales
in comparison to the price of land in cities. We estimate that the total of urban land in the
United States values at well over 25 trillion dollars and amounts to some roughly 50 million
acres at over half a million dollars an acre. And that’s all urban land, not metropolises
let alone downtown Hong Kong, New York, or London, where a single square meter of
land costs more than a hectare of farm land.
Incidentally since I’ll be switching back
and forth between hectares and acres, meters and feet, a lot in the episode, for quick mental
approximation, a square meter is about 10.7 square feet and a hectare is about two-and-a-half acres,
or 4 hectares, 10 acres. A hectare is 10,000 square meters, or 100x100 meters, and an acre is
about 4000 square meters or 43,560 square feet, and there’s 640 acres to a square mile
and 100 hectares to a square kilometer. You don’t need to memorize those, there’s
no quiz at the end, but I felt we should bring those numbers up to emphasize just how
wild the cost differences are. Monaco, the world’s most expensive land market, at over 5000
dollars a square foot, costs more than an entire acre of farmland does in my neck of the woods,
indeed it’s about 60,000 times more expensive.
Out in the country land is so cheap that
virtually all the cost of a structure is building it and maintaining it, in a metropolis
that flips around, the cost of the land and paying its mortgage and property taxes can
dwarf the cost of even multi-story buildings, let alone some ultra-cheap area structures like
barns and warehouses. We normally put the price of a commercial greenhouse at around 25 dollars
a square foot, so greenhousing in an entire acre would run around a million dollars, a hectare
about 2.5 million, both about double the cost of average urban real estate, again not downtown
metropolises where it can be several million.
Obviously the land cost is trivial there for
rural examples, and indeed there places you can still buy land for under a thousand an acre
from a combination of remoteness and bareness and greenhousing those places, like a region cold
enough to be permafrosted, can suddenly change that land into prime agricultural producers.
And yet the savings for building there, rather than on existing prime land, is trivial
too and possibly non-existent considering you’re trying to build far from existing infrastructure
too. On the flipside, sure we can find an abandoned warehouse in many a city and convert
it into vertical farming or a big greenhouse, but even for the purpose of freshness, we might
be better off buying 100 acres of farmland and making that warehouse a top-notch
supply and distribution center instead.
This is a futurism channel though, so we’re not
interested in the economic viability of vertical farming or greenhousing today, we’re interested in
it down the road. Right now there’s only 8 billion of us, and many do think the population will
stabilize at around 9 or 10 billion. Personally I doubt that because the background thought on all
of it is that having more folks than that, or even that many, uses up our resources. But as long
as the cost of food is only a fraction of what a human produces overall, you can keep expanding
– or in this case, doing more with less land – and greenhouses, hydroponics, and vertical farming
are all huge boosters of food per unit area. Indeed enough that greenhouses are already
marginally profitable in many cases. And they get relatively cheaper every year
as we get better at engineering, producing, and assembling cheap but durable glass-like
materials while simultaneously land costs rise.
There’s around a billion acres of farmland in
the US, about two-fifths of the total land area, and even with existing technology we could
easily feed the entire human population with just that space – though a lot of people couldn’t
afford to eat at that cost. Indeed that same tech would easily allow new areas to be converted to
farmland too including flat out desert, because even a few centimeters of rain a year is enough
for a greenhouse since water is mostly contained, and seawater can economically be converted to
freshwater at that point too. It might seem insane to spend 10 million bucks building
some ultra-durable acrylic greenhouse with multi-layered vertical farms and aquaponics
and hydroponics inside designed to feed a thousand people, but if the improvements in technology lead
to a planetary average GDP per capita of 100,000 dollars a year and you are trying to feed 50
billion of us without knocking over every forest, suddenly that becomes economically viable.
And in truth, or my opinion anyway, most of those aforementioned factors seem
pretty plausible in the next few centuries.
Now if the population does end up stabilizing
for a time at around 9-10 billion, how much more controlled-environment farming we see will depend
mostly on overall improvements in material science and automation. We can produce food to feed
hundreds of billions on this planet, but it's way easier and cheaper to feed our current levels
on open-air farming of larger amounts of land.
As an example, the typically 6 to 10 mill
plastic used on most greenhouses is usually only pennies per square foot and those can be
made from biofuels so you can hypothetically greenhouse in land for about its normal rural
cost, carbon neutral and sustainable, and it will be way more than twice as productive if you
do, and there’s a lot that could bring that down. Similarly, the cost for tall buildings is
usually predicated on them being sturdy and safe as residences and office space, not as mostly
for plants, robots, and a few human inspectors. If agriculture shifts to a more
robotic and controlled environment, because we’ve got our robots good enough to run
most basic agriculture with human oversight, then vertical farming might be much more viable.
Now there is a fundamental limit of sunlight, only so much comes down on a given area, and while
you can intercept light destined for different chunks of ground by building tall and putting
other bits of land in your shadow, taking their light, it isn’t terribly likely that in most
cases that would serve any practical purpose. So super-tall vertical farming is
really more the realm of arcologies running on fusion power or power satellites,
see those episodes for discussion of that.
Today we’re still focused on the relatively near
term - the 21st century and maybe the 22nd - and we’re not really contemplating off-Earth
Agricultural here either, space based or on other planets. Here we are talking about 10-20
levels of plants stacked up, possibly a bit more in an urban environment where you might borrow
the sunlight falling on some other building nearby like a warehouse or storage garage where they
aren’t really interested in windows anyway, and you can install mirrors, or just leave
the building in your vertical farm’s shadow..
Now getting that light there
offers a lot of options, you can build to just let the light come in but
you also have options for mirrors or even for growing plants up bundles of fiber optic cables
connecting back to wherever the light source was, which could be kilometers away given how
good fiber optics are at carrying light. So too, while we’re not focused on space options
today, we often discuss power satellites, and shades and mirrors as a beneficial and maybe
even a necessary part of future civilization, even perhaps this century, and have some of
that orbital infrastructure – handy for power generation and climate and weather control
- devoted to beaming down light to some rooftop lenses for distribution to a vertical
farming site, and this is definitely doable.
However, let's take a look at a current production
to see the situations and challenges as they are now. As of currently, vertical farms of several
stacked layers run about twice the start up costs of greenhouses, and are often running supplemental
lighting for the plants – which isn’t necessarily costing extra as you can use that minimal
tailored-spectrum light for heat as a byproduct and plants like heat. I mention that specifically
because people like to eat all year round but precious little grows in the winter, and
even heated greenhouses are limited in this role whereas multi-layered vertical farms do a lot
better at staying warm for less expenditure.
One thing going for the vertical farming market
is the total collapse in LED lighting costs. LEDs are not only stupidly more efficient at producing
light than old incandescent or even fluorescents, they can also be tailored to photosynthetic
spectrums. Indeed they can be tailored not just to the frequencies plants tend to like, but
the specific frequencies a specific crop likes, and like at that time, as how much and
what kind of light a plant wants can vary. Seedlings need little light compared
to their future plant, for instance. How much light of what wavelengths, and heat and
humidity, for how long each day, and for a current time of day and current time of year or maturation
period, can all be controlled and the production booms when you do, particularly if contrasted to
the normal sunlight hitting a chunk of ground.
Long term it won’t just be LED lights either, we
might see stuff like semi-transparent greenhouse glass that transmitted the photosynthetic
frequencies through for the plants but reflected non-photosynthetic light down on to solar power
collectors or thermal heat mass in the greenhouse meant to keep it warm at night. This is
a lot of what I mean when I say we have problems discussing vertical farming separate from
controlled environment agriculture, because the two tend to be innately intertwined. If you’re
building a structure to be climate-controlled, you might as well take advantage of the
multi-level tray of plants you can do in it. Even without supplemental lighting, just by
being able to cut out the natural seasons, and thus have some plants growing in
seedling phase, using little light, near ones that are using more form being
more mature, adds to productivity.
Economically, fresh food that I can grow in the
winter and put in a supermarket in a city on the same day can sell for a good premium, and the
competition is better storage or cheaper rapid transport from further away. I want to emphasize
that though, because we are getting much better at storing stuff in ways that prolong its freshness
and obviously we ship way faster than we used to.
And we could see some weird hybrid innovations in
that too. We’ve a long history of truck farms, but contrary to the implication, it has nothing to do
with growing food on a truck or transporting it to market on trucks, it's just a perversion of the
old north French word ‘troquer’ meaning barter and exchange, in reference to small market gardens of
a handful of acres; folks would bring produce into cities from. However we could see that term become
properly literal in a future of automated freight, fleets of trucks holding vertically-farmed produce
could be operational, with one parking right outside someone’s house to deliver produce that
a robot just harvested from that truck 30 minutes after someone ordered it. It might even be carbon
neutral from using its own exhaust for travel and supplemental lighting for the CO2,
water vapor, and heat the plants relish.
You get some weird scenarios with low-level
AI in any economy, especially a post-scarcity or borderline post-scarcity economy as
is basically inevitable with such AI. Contemplate a civilization where most people’s
homes were semi-off grid in terms of having in-house water and sewage recycling and some
small automated garden that grew its regular crop, and where animal-intelligent robo-trucks
swung by to deliver orders for less-used foods or a sudden need for extra quantity, tanked up
off your sewage for partial payment, and meandered off to their next delivery. Recycled shipping
containers are currently a popular option for housing vertical farms, and I could well imagine
skipping the recycled part so that the farming was in shipping containers and vehicles just picked
them up when ready to deliver. Possibly in a weird parallel to crabs changing shells.
Bit of a tangent into more of the scifi realm than science for the moment, but I could imagine
civilizations having an almost human-pet relation with such food trucks or have roaming
fleets of entire wild stray trucks, animal intelligent and parking wherever they
could steal some sunlight and begging at doors for food scraps and waste and repairs in exchange
for fresh herbs and greens. Like I said, you get some very weird scenarios in a civilization
with low-level AI, especially if it's smart enough to play at being cute and appealing to
why we like kittens, puppies, and little kids.
Anyway Vertical farming has to potentially compete
with weird new innovations like that, and is a reminder that improvements in technology in a
different area can sink another area we expected to do well in the future. Though that example also
raises some market for it, being able to convert rooftops, basements, or garages into home gardens.
Automation makes that a lot more viable, from both the overall increase to human wealth and the ease
of maintaining a garden if you’ve got robots doing most of the grunt work. It might seem like we’re
pessimistic on vertical farming in this episode, we’re not, and indeed that sort of home vertical
farming is something I can practically guarantee will explode in the next couple decades.
That’s hardly a niche market either.
And neither is that rapid ability to get
fresh food from farm to fork in mere hours and any crop at any time of the year. If you
want that, you either need climate-controlled agriculture or amazingly good global transport
and distribution, and if you’re doing climate controlled, then the conversion to vertical
farming isn’t much extra, indeed it's usually necessary to make it profitable. But we
shouldn’t ignore that the aforementioned amazingly good global transport and distribution
option is probably also going to become a reality. Which one wins out, or if the two can
simultaneously exist, is likely to be dependent on unpredictable factors, tiny differences in cost of
thus far undeveloped technologies could make the difference, so could international strife making
food security a bigger concern. Heck, a lot of human history is an ongoing conflict not between
neighboring realms but the cities in those realms with the countryside that feeds them, and same
as things like online shopping and 3D printing can lessen rural dependence on big factories and
retail centers, vertical farming could lessen the feeling of food security for folks in cities from
rural areas, a historical exposed jugular artery.
If I were a cynic I suppose I’d be worried
those options might make conflicts between them and shifts to city-states more common in
the absence of that shared interdependence… thankfully I am not. I should note though that
while vertical farming offers the ability to cut down on travel time and distance for goods
to urban areas, it still isn’t likely to see truck farms – the traditional kind – adapt to
vertical versions in the middle of downtown, just on the outskirts where land and
building costs aren’t too prohibitive.
I mentioned earlier how the cost of urban
agriculture can often be misleading because of how much is being done with discarded
materials or abandoned buildings and land, but it is worth noting that there is likely
to be a lot of that in any given city and the economic viability of
any project is pretty holistic. If I can take over an abandoned old warehouse
covered in graffiti and weeds and turn it into a small vertical truck farm, I can probably
also get a small market and deli in there, maybe get a grant from the city or a foundation
aimed at helping restore that neighborhood, and then sell the whole thing down the road
when land and building prices rise nearby, due to my improvements. Again that’s a niche
market approach but hey, there’s a lot of niche markets in a civilization of nearly 8 billion
and rising, over half of whom live in cities.
I would tend to bet that a vertical farm,
especially one with transparent sides of a nicely insulated acrylic or polycarbonate, would tend
to work as well as garden parks and greenspaces at all the things those are touted for, which
is everything from actual medical health to psychological wellbeing, lower crime, higher
property values, and more. So again any costs for making them need to take factors like that into
account but at the same time would probably be of diminishing value as the number of them grew.
Also, we should note that major use of vertical farming is likely to also be tied into not
just hydroponics and aeroponics, since heavy trays of dirt come with their own problems,
but also aquaponics since it's such a good way to handle storage of water and heat, and for
that matter creation and recycling of nutrients. Cities need vast grids to handle their water
and sewage use, if you can narrow that down so that the water and sewer recycling for any
given neighborhood was in the basements of a couple local vertical farms, all within walking
distance and open to strolling through, you’d be cutting down on the huge cost of water and sewer
infrastructure in metropolitan regions and in a way that’s like to be positive and appealing
to many folks, and possibly profitable.
It’s also one possible way to reclaim abandoned
underground tunnels and mineshafts, and ironically one approach to carbon sequestration
back into some of those mineshafts.
Vertical Farming and controlled environment
agriculture in general tends to be vastly superior in water use, fertilizer use, and problems
with disease, contamination, and pesticides, so that’s another aspect to put on the
balance scale against the sheer price difference compared to open air farming.
They are much easier to quarantine and thus also safer for using GMO crops which might be
invasive to an area, but highly productive.
All right, so what’s the takeaway? Will
we see vertical farming in the future? Certainly, it already is in use, just principally
in niche and premium markets. But it's growing, and as we grow ourselves, hoping to keep more
people while hopefully not needing to make new farmland to feed them, I think we will see a
big rise in vertical farming, so to speak.
Somewhat surprisingly given how important
agriculture is to humanity, it tends to get undermentioned in science fiction and only gets
surface dips rather than deep dives as a topic. Probably one of the biggest exceptions
to this is Farmer in the Sky by Scifi grandmaster Robert Heinlein, which looks at
a farming colony on Ganymede built to help feed an overcrowded Earth and the journey
of a young man out to join that colony. Farmer in the Sky is one of the roughly
dozen books Heinlein wrote for Scribner as young adult scifi and is also counted as part
of his Future history series, so is a very good gateway into one of Science Fiction’s most
fundamental and influential authors, and it got a Retro Hugo Award in 2001, as the novel came
out a couple years before the Hugo Awards began. 70 years later Heinlein’s works still
resonate with audiences, young and old, and I’m very happy to add him to our very
short list of authors who have won our SFIA Audible Audiobook of the Month more than once.
We gave him it some years back for Starship Troopers, which was ironically rejected from the
Scribner series. We’ve been doing the Audiobook of the Month for six years now and other
repeat winners are Isaac Asmiov, Larry Niven, Alastair Reynolds, and Arthur C. Clarke, so he’s
in good company, and each of those authors has a huge binge-worthy catalog of novels available
from audible. I would like to go ahead and thank Audible too, they are our very first sponsor for
the show, going on six years, and I’ve been a customer of theirs for almost thrice that now.
Hopefully you’re getting to do some traveling to see friends and family this holiday season and if
so, audiobooks are a great companion on long car, plane, and train rides, as well as for exercise
bike rides for working off the holiday calories, and Audible is is now offering 60% off their first
three months of membership so it is a great time to join or if you are already a member, to give it
to someone as a gift. Audible also has a lot more than just audiobooks now too, like their Plus
Catalog, which gives you free access to a huge collection of podcasts, Audible Originals, guided
fitness, meditation, sleep tracks, and more. As always Audible member’s get 1 free premium credit
a month to use for all those new bestsellers or classics like Farmer in the Sky, and you get
the member discount on additional purchases, but it's awesome having free access to all those
podcasts and shows for streaming and download and it’s definitely my favorite new feature they’ve
added. To give them a try, and get 60% off the first three months, just visit Audible dot
com slash isaac or text isaac to 500-500.
All right, next week we’ll be examining the
notion of intergalactic colonization with a twist, as we try to see how a lone ship or nomadic fleet
might escape a hostile galaxy and survive as a civilization. Then next Sunday, the day after
Christmas, I hope you’ll join Sarah and I for our last monthly livestream Q&A of the year,
at 4pm Eastern. We’ll then finish out the month and year with a look at the Challenges
we will be facing in the next 100 years.
Then we will explode into 2022 with a look
at using Nuclear Bombs to propel Spaceships. After that we will revisit our most popular
series, Alien Civilizations & Civilizations at the End of Time, first for a look
at hibernating alien civilizations that might be waiting till nearly the end
of time, then for a look at the Big Rip, the cosmological model that ends the
universe early and by being shredded, and we will ask how civilizations might
manage that, or manage to survive that.
Now if you want to make sure you get
notified when those episodes come out, make sure subscribe to the channel, and if you
enjoyed the episode, don’t forget to hit the like button and share it with others. If you’d like to
help support future episodes, you can donate to us on Patreon, or our website, IsaacArthur.net,
and patreon and our website are linked in the episode description below, along with all of our
various social media forums where you can get updates and chat with others about the concepts
in the episodes and many other futuristic ideas.
Until next time, thanks for
watching, and have a great week!
