Image: Kenn Brown Mondolithic Studios
In Brief
- Farming is ruining the environment, and not enough arable land remains to feed a projected 9.5 billion people by 2050.
- Growing food in glass high-rises could drastically reduce fossil-fuel emissions and recycle city wastewater that now pollutes waterways.
- A one-square-block farm 30 stories high could yield as much food as 2,400 outdoor acres, with less subsequent spoilage.
- Existing hydroponic greenhouses provide a basis for prototype vertical farms now being considered by urban planners in cities worldwide.
More In This Article
Together the world’s 6.8 billion people use land equal in size to South America to grow food and raise livestock—an astounding agricultural footprint. And demographers predict the planet will host 9.5 billion people by 2050. Because each of us requires a minimum of 1,500 calories a day, civilization will have to cultivate another Brazil’s worth of land—2.1 billion acres—if farming continues to be practiced as it is today. That much new, arable earth simply does not exist. To quote the great American humorist Mark Twain: “Buy land. They’re not making it any more.”
Agriculture also uses 70 percent of the world’s available freshwater for irrigation, rendering it unusable for drinking as a result of contamination with fertilizers, pesticides, herbicides and silt. If current trends continue, safe drinking water will be impossible to come by in certain densely populated regions. Farming involves huge quantities of fossil fuels, too—20 percent of all the gasoline and diesel fuel consumed in the U.S. The resulting greenhouse gas emissions are of course a major concern, but so is the price of food as it becomes linked to the price of fuel, a mechanism that roughly doubled the cost of eating in most places worldwide between 2005 and 2008.
This article was originally published with the title The Rise of Vertical Farms.
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65 Comments
Add CommentI was ok with the article and in agreement about the desirability of moving crop production indoors, but wondered why it needed to be vertical.So I did some sums. In eastern Britain arable land gets about 1000 kwh of solar power per annum per square meter. Even LEDs only produce less than 50% of the input energy as light - but assuming that they provided enough at that efficiency, that would mean for the 30 story example quoted the installation would require a thousand megawatt power station for the lights alone. Apart from the roof top the amount of daylight the rest would receive would only be a function of the longest side and the depth of the level.I have long argued that farming should "come in from the cold" with hermetically sealed growth houses using the various types of "ponics" and condensing moisture out of the internal atmosphere for recycling. Most water is used by plants for evaporative cooling of the leaves.Crop yield is related to the amount of light it receives so it is not something to be skimped. Even if one was thinking of going vertical, you could not have them near each other or other high buildings from the shading. I would like to read the reaction of the advocates as I may have got my sums wrong. Another way to do the sums is from the anticipated yield. Assume that each acre produces about 3 times the world record wheat yield ( 48kg per metre squared, and wheat about 15 megajoules per kg ) and did it with a photosynthetic efficiency of 6% , then the power per metre squared comes to 380 watts per metre squared, which for 2400 acres comes to 3,648 megawatts - which is a lot worse !!
Reply | Report Abuse | Link to thisEven if you set the photosynthetic efficiency at about the theoretical maximum of 11% and put the yield down to 16 kg per metre squared, this reduces the power to about 69 watts per metre squared, or 662.4 megawatts.
The more you look at it the worse it gets. If you are using something like 600 Mw most of that will degrade to heat in one form or another. Getting rid of that heat would be a major problem and probably require a further 200mw, or more( using heat pumps and selling it for district heating in winter, and storing it in subterranean rocks in summer). Even without that cost, if you are buying electricity at only $50 per megawatt hour, you are still spending over $300 million per annum ( or $125,000 per acre ). The food produced would be hugely expensive, and that takes no account of the environmental impact of a large power station dedicated to the production of only a few thousand acres. You might note that I have made no allowance for the power required for other aspects of the design, but at first glance it would seem that the authors have little appreciation of the costs of such elaborate arrangements.
Reply | Report Abuse | Link to thisCertainly, Dickson Despommier’s description of vertical farms (“Sci. Am.” 11/09, p. 80) is intriguing. But before we all jump on the elevator, it would be good to take his statistics on the amount of land being used for growing livestock and growing food and subject them to closer analysis. For example, how much of the total is used for growing crops such as soy beans or corn the principal purpose of which is animal feed? How many thousands of acres are taken up to grow corn the sole use of which is to create high fructose corn syrup with which to sweeten all manner of foods, whether they really need sweetening or not? And so on.
Reply | Report Abuse | Link to thisIn the absence of such analysis its difficult to see how Despommier’s plans will make a significant difference, for its not in the growing of tomatoes and cucumbers that most agricultural land use takes place. Despommiers should ask some of the gigantic agribusiness concerns he suggests should be participants in his scheme—such as Archer Daniels Midland, Monsanto and Cargill—whether they would be prepared to concentrate on real food crops and not on those which make the meat, fast food and soft drink industries happy. And why invite into the scheme some of the worst despoilers of the natural world?
In other words, unless his plan is accompanied by a significant change in dietary habits and serious restraints on agribusiness, not a likely proposition, it can only partially address the real issues. Vertical farms might provide some relief, but what about the amount of acreage now being taken up—or created by deforestation—for the cultivation of bio-fuels? Farmed indoor?
Prof. Mitchell Lifton
Portland OR
I am concerned that we are recommending a step away from the way this planet is designed to produce food. The main problem is overpopulation, and unless the population is reduced, civilization is in grave danger. It might already be too late, anyway.
Reply | Report Abuse | Link to thisI find it difficult to understamd how Scientific American could even publish such as silly article. Wasn't this article reviewed by anyone in agriculture or for that matter anyone growing plants. Plants would not grow in this shade and artificial lighting as in the other replys show is so costly that it is not remotely close to reality. I'll go elsewhere for fairy tales.
Reply | Report Abuse | Link to thisI must apologise to readers because I got some of my figures wrong by a factor of 10 times. . The world record wheat yield is about 16 tonnes per hectare (1.6 kg per m^2 ). This still means that the proposed installation with a projected output equivalent to 2400 outdoor acres would need a lot of electrical energy. One tonne per acre is a modest yield for outdoor wheat and given that the photosynthetic efficiency of wheat is no more than 6%, would imply a light source emitting 21.56 Mw, and as lghting is only about 50% efficient , at best that means a power supply for the lights of about 43 megawatts . At $50 per megawatt hour that gives an annual bill of $18,834,000 for the lights
Reply | Report Abuse | Link to this> unless the population is reduced, civilization is in grave danger.
Reply | Report Abuse | Link to thisHow would you go about reducing the population?
thats what i am saying, the human population is the real problem, unless we do something about it no solution will last long.(China actually had good idea with trying to limit that but the problem was "How"). I think people should look into adopting child instead of wanting there own, and also these days, 16-17 year old have children which they cannot take care of which leave them with adoption, or kill the child(i consider it killing, you might not).
Reply | Report Abuse | Link to thisTo simplify this "vertical farm" model, think about it this way; there is only so much sunlight per square foot available. "Stacking" the plots does not accomplish anything other than increasing the area available for planting. Sunlight is still required for the plants to grow. A tall "greenhouse" will just cast a longer shadow. Electric lighting will not be efficient, energy (electricity) is in much shorter supply than land. Also, tall buildings are very expensive to build and maintain.
Reply | Report Abuse | Link to thisCome on, SciAm, you can find more plausible bunk than this. Please!!
Fiber optics!
Reply | Report Abuse | Link to thisThe point to make here is about the amount of arable land available. Certainly we have a lot of marginal land out there. The vegan activists consider any land with animals on it wasted, but there is much land on which one can graze cattle but not raise soybeans. However, even the driest patch of desert gets sunlight or second-order solar-derived energy (like wind). If we harvest this otherwise wasted energy and pipe it to where water is available for high-intensity (possibly high-rise) farming, we can certainly envision growing more food.
Reply | Report Abuse | Link to thisAgreed with krohleder that fiber optic lighting would significantly reduce how much power is needed for additional lighting. Then add the the sold biomass (presumably for fuel) and the operating cost of such a facility goes down further. Now let's presume that the costs are subsidized by taxes... suddenly the costs don't seem so high, do they? 18M is a small number today, and one that I believe is over-estimated.
Reply | Report Abuse | Link to thisI wonder if the best way to overcome issues of energy and spoace efficiency would be to short-circuit the divisions between the plant and the structure, for example, a surface on the end of a fertilizer tube could be engineered to host a grafted segment of a plant stock, thereby allowing the structure to take over the role of the plants roots. Leaves could be superceeded as well if the energy and nutrients they collect could be delivered to the core of the plant directly instead of through UV lights. I know it's a strectch, but could the plant become a plant in both senses of the word? a city-block sized cybernetic vegetable?
Reply | Report Abuse | Link to thisWhy did this arise? Maybe because we have turned all the good farmland into pavement and houses and are continuing to do so.
Reply | Report Abuse | Link to thisI'm currently doing graduate work in architecture--vertical farming is one of the hot topics, and sometimes it feels as if I'm one of the few skeptics.
Reply | Report Abuse | Link to thisI've asked many of the same questions raised here. I give SCIAM the benefit of the doubt regrading vertical farming's physical/mathematical plausibility, but wish the editors had asked the article's author to address obvious incongruities, instead of just writing a puff-piece.
For example, while growing surfaces might be tilted from horizontal to match latitude angle, thereby capturing more intense sunlight and increasing effective acreage (by ~1.4 x for 45* lat.), farm buildings will still have to be spaced well apart from each other to avoid shading, with taller buildings=longer shadows= greater spacing. Greenhouse conditions mean plants can be grown year-round; perhaps acreage is then effectively doubled or tripled. Taken together, this suggests a 1 acre VF building footprint might yield the equivalent of 4.5 acres of traditional farming, at best.
Artificial lighting seems like a non-starter--the best solar panels run maybe 20-25% efficient, and Wiki gives theoretical maximum for photosynthesis as 25%. Even if electricity from the panels could be converted back to photosynthetically active light without losses that means only 6.25% use by plants, for a back-of-envelope wildly optimistic limit--given that plants already use something like 2-4% of natural light, this is no improvement. Perhaps naturally growing plants are chronically overlit during summer, and VF takes advantage of that--I don't know, and the article doesn't say.
What about fertilizer? Modern high yields depend upon it. Synthetic fertilizer uses natural gas as a feedstock, consuming fossil fuels and releasing CO2. Fertilizer could be synthesized using hydrogen produced by solar power, but this needs more land for the panels. Non-arable land, maybe, but again the article doesn't begin to cover this.
For me, the biggest problem is this: a vertical farm is a very expensive, high tech structure, only possible in the developed world. The problem of too little land and too many mouths will affect us last, just as it always has--by the time we need vertical farming, the planet will be heading down a slope so steep there'll be no stopping it.
Anyone who thinks VF will be the developed world's gift to Africa and other developing areas is kidding themselves--clean water and TB treatment are far more pressing needs than shiny condos full of hydroponic tomatoes, and no one has managed to supply that.
More back-of-the-envelope fun:
Reply | Report Abuse | Link to thisScots Engineer has an interesting approach, using food produced as a measure of the energy required to produce it. With that in mind, let's examine Despommier's claim that 1 square block can produce as much as 2400 acres.
First, "square block" is ambiguous. Giving benefit of the doubt and assuming a large, ~6 acre block typical of the western US, we have 2400/6=400% increase in yield, vertical farming (VF) vs. traditional farming. (With smaller blocks, his claimed increases would be more like 1800%)
So what do traditional yields look like? Online sources give current global arable land as 0.6 acre/person--assume this means 1 acre will produce ~3000 kcal/day averaged year-round (1800 kcal/person/day--less that US RDA, but above starvation).
400% greater is 1.2 million kcal/acre. Since 1 acre ~ 4000 square meters, this is ~ 300 kcal/m^2.
Is this possible?
Global average solar flux is 164 Watts/m^2. Of that, the most efficient plants can convert ~6% to biomass (total, including inedible material). Theoretical maximum efficiency for photosynthesis from natural light is 11%. So, ~10 W/m^2 is available to the most efficient plants, under real world conditions. This is 240 Watt-hours/day, or 0.24 kWh. 1 kWh=681 kcal, so 1 m^2 could yield 163 kcal/day of total biomass, assuming no space between plants, etc.
163<300. Oops.
Despommier claims almost twice the yield possible from the solar energy available at a given site (at least outside the tropics). Stacking up floors doesn't change that math, as Lowndes points out. That extra energy has to come from somewhere, which is ultimately robbing Peter to pay Paul. Perhaps he does intend harvest of energy on non-arable land, as suggested above (although, using sealed greenhouses and hydroponics, what does "non-arable" mean?) But he doesn't say: just a lot of handwaving about mile-long greenhouses in the Southwest, geothermal this-and-that, and burning New Yorkers' excrement (last I checked, humans had to put at least as many calories in the top end as could come out the bottom, so the math there doesn't add up either.)
Extraordinary claims demand extraordinary evidence. Despommier provides plenty of extraordinary claims, but not much evidence at all, extraordinary or otherwise.
Hi David Drake- I'm glad I'm not the only one who gets a little confused with the fantasy arithmetic of this article.I am both an engineer and a farmer. 6 acres times 30 levels comes to 180 acres and if he is claiming an output equivalent to 2400 acres, that's 13.33 times more ( or 1333% if you prefer ) Managers of glass houses can increase the output from their establishments by intercropping so that all the available light is utilised. As you have stated the theoretical photosynthetic efficiency from day light is about 11% and although the highest numbers of hours of sunlight are over 4000 per annum , when you take incidence into account, most places get less than 2500 kilowatt hours per level square meter per year. If this was used to grow algae in transparent tubes it might still provide a very useful 250 kilowatt hours worth of biomass per square meter per year.This biomass could be used for further treatment to provide fuels, or fed to a well organised food chain resulting in a harvest of commercially attractive fish and crustaceans.
Reply | Report Abuse | Link to thisAs has been commented elsewhere water ad fertiliser look more likely to limit agricultural output than land ( or sea ) area. Nitrogenous fertilisers don't HAVE to use fossil energy sources, it is just that they are the most economic at present.In the organic farming debate it is germaine that the extra energy value from the increased yield of conventional over organic more than covers the energy cost of the fertilisers ( including disribution and manufacturing costs ). Organic then needs more land to produce the same amount of food sustainably. I too am a bit disappointed that the editors of Scientific American do not require a higher standard of verification for claims and "facts" in articles
How about taking this VF in a slightly different direction by building food pyramids instead? Angled sides could expose a much larger area to direct sunlight, although there is still going to be a limited time for each side to receive solar rays. Just a thought.
Reply | Report Abuse | Link to thisI expect plagues myself to resolve the issue of what to do with too many people. Starvation is next most likely. Procreation is too much a part of us to vanquish quickly.
Reply | Report Abuse | Link to thisI recommend that we as a nation, depart from all foreign lands and protect our borders. The decline of the cheap energy upon which we erected the current insecure status is about to end.
When this happens food will emerge as the true world resource and we will need to defend our arable lands from encroachers.
I suspect that I will be dead by then. Perhaps to become Soylent Green.
Cheers.
Another way to look at it: world arable land is ~4 billion acres. Depommier claims that needs increasing by 20%, or an additional 800 million acres. Taking his (dubious) productivity claims at face value, that would still be something like 300,ooo 30 story vertical farms, with 5 acre footprints. Total square footage per farm would be something like 6.45 million SF, which at a VERY modest construction cost of $100/SF would be $645 million each, or ~$194 trillion for all 300,000 VFs. Kinda puts the national debt in perspective.
Reply | Report Abuse | Link to thisDid anyone mention that as soon as you pack so much into so little space, the blights and funguses that are kept in check (to a degree) by outdoor weather and distances between fields, etc, would *sweep* through these structures before they are even noticed? They tried "fish ranching" in the ocean with salmon, et al, and have found that the artificial density these fish are being kept in is a parasite's heaven.
Reply | Report Abuse | Link to thisWithout even addressing the total unfeasibility of inexpensive ways to deliver proper lighting, etc., the issues of disease, blights and parasites have to be addressed as well, and this type of structure makes it an all-but-unwillable battle.
One option (and I was maily concerned about light upon first reading of this) is to reserve the outer rings that do get light for plants and use the inner spaces for vermiculture to create your own compost and fertilizer, and consider aquaculture of fish, shrimp, mussels, etc, that could be fed off the bacterial from water as well as create enriched water that is itself, fertilized for the plants.
A delicate balance could be achieved, but it is not nearly as simple or "cheap" as this article implies. In fact, I am convinced it could never compete economically with the present system and will only come about when nature and the Feds mandate it.
All good points, but nobody commented on the benefits to the planet's aquatic environment. However the energy is generated and paid for, keeping the water clean around the planet might keep us and all other life alive and healthy. If technology can bring farming indoors and even in a stacked arrangement, then I'm all for it. Green roofs on all buildings to produce local produce would be a start. Get invloved with you local govnernment!
Reply | Report Abuse | Link to thisI am a studying horticultrist in my last year with a minor in nature. Nice to get some feed back from other professions.
Reply | Report Abuse | Link to thisThere are low cost systems as well to produce for small house holds and biofertilizers that work better than the commercial ones but the knowledge to produce them has been lost or scattered a bit around the world because each area or country has its own resources that contribute to the quality of food produced.
In vertical farming the cheapest systems that I have seen use is an old coffee bean sack in Africa with pinholes to the side for plants and plants to the top and in Europe, a bed pinned to a wall in a 1st world country was used to grow food and ornamentals. Even though it is a small start, both helped the owners reduce their food cost even marginarly. The truth is we have to chose plants that can grow and produce locally without to much input. Dandelions are a good example as it is considered a weed and used as a crop for salad in some countries.
There are alot of fertilizers that do not deliver optimum nutrition but produce wonderful fruits and vegetables. BRIX levels should be taken into account with food more often. This can be seen in the decomposition time, armoas and taste. Bio fertilizers can be made from waste and reduce 1/3 of what goes to landfills.
I believe it will contribute but will be among a series of solutions that depends where it is being implemented and the circumstances around it. Good selection of crops and spatial planning as for natural vertical areas and crops areas will matter as well.
But both Scots engineer and you raise some valid points. Galaxy man had a good idea about light with pyramids and Japan had a concept about a city built along those ideas for maximum light and productivity.
Hi acquasci - you raise many relevant points. What seems clear to me from the comments on this and other topics is how difficult it is to change a popular mind set, even though you have robust figures to back your argument. Professor Despommier is allowed, if not encouraged, to advocate an extreme solution to problems he assumes have no other rational remedy. If I or anyone else who was not in a position of academic eminence made these suggestions we would not get a hearing, and certainly not publication in a magazine of SA's standing. Some of you may have heard of that great american scientist and engineer Robert Goddard, who pioneered liquid fuelled rockets. He also made detailed proposals for Evacuated Tube Transport before his death in1945. He rightly identified air resistance as the largest impediment and energy cost in high speed transportation. This has not changed,but all the elements for a successful system are now available in other roles. I estimate that US replaces more than 10 million vehicles per annum, and that equates to about 10 million tonnes of steel ,or more. 10% of that would build 1000 kilometers of double steel tubes ( one for each direction) capable of resisting atmospheric pressure by a comfortable margin. Most, if not all the world's high speed trains are heavily subsidised, noisy and fatal to any wildlife that gets in their way. They are just as affected by bad weather as other transport means, if not more so, yet ETT ( evacuated tube transport ) should be unaffected. I have read Scientific American for decades now and can remember no article exploring this issue in recent times. Most of agriculture's woes are down to speculative commodity markets and the bias in large corporations towards seeking power, but avoiding a commensurate level of responsibility. Please messrs editors find someone who can put forward arguments for genuine advances so that we can hope that the past's mistakes are not endlessly repeated.
Reply | Report Abuse | Link to thisHi xenoclone - perhaps you could enlighten me ( no pun intended ) on fibre optic lighting. In my ignorance I thought that fibre optics transmitted light from one place to another, but did not actually transform electrical or chemical energy into light. If I am indeed correct then by the law of conservation of energy the fibre optics would need a large area from which to collect daylight, or a large number of artificial light sources which would have the energy demand already talked about. Turning biological wastes, dry, or otherwise does not produce a large amount of energy per kilo . At best it can produce about 5 kilowatt hours of heat per dry kilo, but this translates to only about 2 kilowatt hours worth of electricity and that gives less than 1 kilowatt hours worth of light energy. Even if that light was all in the photosynthetic band no more than 25% could end up as fresh plant material. If you are going to burn your biomass for fuel you have less to sell as food, - there is only so much you can get for the inputs you apply, and that is where the author's figures don't add up.
Reply | Report Abuse | Link to thisIt is amazing how it is taken for granted in a so called scientific piece that water used for irrigation is lost foreever. It's simply not true. Although there have been problems with certain pesticides (DBCP) for the most part percolation through the earth purifies the water for re-use. For example the city of Fresno, CA has a contract with the Fresno Irrigation District whereby the district's customers irrigate acreage upslope from the city so the water goes back into the ground and into the city's underground water supply. The city's water is among the best in the U.S. As one area water expert put it "We use and re-use water until we wear it out." We, as a people are in real need of scientific evidence of what is really going on in our world. The recent trend of political slanted so called science has got to come to an end or we will lose all faith in science altogether.
Reply | Report Abuse | Link to thisVertical farming to me can be used but not as a sole solution to all the problems for food production because certain areas..simply do not have the light between current spatial planning to produce crops. But these areas can be covered with native plants that can use Co2, insulate buildings and provide habitats for some birds and food webs. These native speies of plants and animals can benefit from these areas not used for food. In other words green vertical spaces that need minimum care in hard to reach areas would still be beneficial if planted with native occuring wild plant that will require minimum attention. Designs done in England with vertical farming, a whole hotel building makes me believe that this is the future for these structures. Yes I do beleive its optional to small households to extend their productivity with vertical farming on a small scale. If person did a bit it would add up to more food but not as total food solution.
Reply | Report Abuse | Link to thisAquatic systems protection (topic 2)
Many aquatic systems can benefit by turning to bio fertilizers and systems to clean black water and grey water and use them in crops. This is proven to work by the European Space Agency (ESA) Project MELISSA that does just this is Spain by creating a closed system for production. These systems can be realised in larger aspects and then localized to indivual buildings or cities. Grey water can be used for algae production while black water processed to biofertilizers, heat and energy. The exact amount produced, I am not sure and was trying to get the figures myself. This sysetm uses the waste proudtcs as raw resources for a next process in the system.
Traditional horticulture
Fertilizers that are processed via composting then vermicomposting can have minimum run off problems to lakes and water cycles. The soil sub levels do filter out chemicals and pollutants but prevention is better than a cure. Bio-fertilizers that lock and store the nutrients in the top soil by their molecules are benficial. These fertilizers can be totally broken down by microorganisms in the soil(fungi/ bacteria). But this can only be done by stepping a way from traditional chemical culture which is more reliable because it is percise in nutrinets while organic fertilizers like these vary in nutrients based on the input.
Lights
Fiber optics can help in some situations, Led is possible but not now, Sulphur plasma lights are interesting but energy consumption and price is still high but full spectrum. (did not enough space to write detailed)
all a bit like chicken farming: could make a fortune selling eggs! as with irrigation, doesnt everything 'glom' up after a while - just suspect there are all kinds of hidden problems.. julian rowe
Reply | Report Abuse | Link to thisI wrote about vertical agriculture in my 1995 book "The Automated Society." In order to automate agriculture I went to a high rise building providing food for a community of 10,000 people. My food building would be taking in sewage and garbage and using algae turing the waste into either algal food or fertilizer and producing food. This would be a close system virtually.
Reply | Report Abuse | Link to thisI had hoped that NASA would have done the research needed to get a closed agricultural system going for long space voyages, but they have felt they could let it go for the time being. Sooner or later, the human society will be totally automated and high rise agriculture is the answer. But the capital investment and operating costs will kill the idea for as long as outdoor agriculture is effective.
I would have hoped that Dickson Despommier had mentioned by book as a base for his ideas for vertical farming.
I have not read Masse Bloomfield's book, but I find his comments really scary. The idea of a totally automated society seems pretty inhumane. Where is the role and fulfillment for most of the population if everything is done by machine, including maintenance and repair?. Millions are already unemployed and many more are on drugs to help cope with their empty lives.Many are not suited to the professions that would be left and competition would be even more intense. As an agricultural engineer I find the thinking behind vertical farming both urban obscessed and woefully ignorant about both agriculture and engineering. Are they so distrustful of the transport and retail industries that they would happily use many orders of magnitude more energy ( which they don't say how they are going to get , or pay for ) rather than convey food in from the country or sea. The mis management of biosphere 2 was a tragedy which is costing us all. It was and is important to develop closed system agriculture not just for space travel, but to tackle climate change and over population . Closed system does not require, or imply verticality. For an individual urban property owner it has some benefits, but not as a means of feeding a city, or dealing with it's wastes.
Reply | Report Abuse | Link to thisMinor error in one of my posts above--I wrote 400% but meant 400 times, which is how I did the rest of the math. I used the footprint of a "square block" building to calculate Despommier's claimed efficiency over traditional farming, rather than 6 acres times 30 floors, as the area of solar collection can't be much more than the building footprint. In other words, his claim is that 1 acre of land occupied by a vertical farm is as productive as 400 acres of traditional farmland.
Reply | Report Abuse | Link to thisRe-reading the original article, it appears Despommier arrives at his 2400X claim by guesswork:
"...let us say that each floor of a vertical farm offers four growing seasons, double the plant density, and two layers per floora multiplying factor of 16 (4 � 2 � 2). A 30-story building covering one city block could therefore produce 2,400 acres of food (30 stories � 5 acres � 16) a year. ... Of course, growing could be further accelerated with 24-hour lighting, but do not count on that for now."
No reason given for why a daylight greenhouse would have four growing seasons with double the plant density, and why this could be stacked 2 layers per floor. As noted by many here, no indication how the amount of sunlight that normally hits the earth's surface is supposed to multiply and spread out over 30 floors (and why stop at 30 floors, when you have Despommier's magic light? Why not 60 floors? Or 600?)
I note that Scots Engineer (no doubt correctly) assumes more solar energy per square meter than I. And allows the possibility of algae using that energy with near maximum theoretical efficiency. Of course, using algae for food will likely require further processing and decrease in efficiency.
Where I live (47*N latitude) receives an annual average ~4500/Wh/m^2/24 hour day, or 187.5 Watts/m^2 flux, averaged over 24 hours. Using that for my calculations above, I get about 184 kcal/m^2/day. Using 10% photosynthetic efficiency , I get 306 kcal/m^2/day--basically, the same number as Despommier, but this is counting on near theoretical maximum utilization of sunlight--real plants that we are in the habit of eating (the kind he mentions in the article) are nowhere near this good--not even as good as the 6% efficiency I assumed.
Vertical farming has some very smart and credentialed proponents; I wish they would refute these figures, and those posted here by other skeptics, in detail.
Hello Scots Engineer,
Reply | Report Abuse | Link to thisCouldn't agree more, especially with your statement that VF proponents are "urban obsessed."
I'd suggest that part of the problem with too-credulous acceptance of these kind of proposals is that architects and designers prefer to think about what ideas might work (however far-fetched), rather than rigorously consider why some ideas might not (it's hard to draw a negative). Sometimes this approach produces brilliant, inventive solutions--more often it produces fantasies.
With regard to Biosphere 2, I've not studied it too closely, but it seems to me the problem with the concrete and the oxygen was unforeseen, thus, at the very least, we learned something useful for future designs. Probably a more expensive lesson than necessary...
And I'm convinced overpopulation is primarily a social problem, not a technological one. From the example of the developed world, it's pretty clear that healthy, well-fed and educated people don't have many babies (although they do use a lot more resources). An article in this month's Sci-Am suggests population growth has just about erased the gains of the Green Revolution--the last technological solution to feed the world's starving masses.
Hi David Drake- I'd better be careful here not to have people think I'm perpetuating a mutual admiration society. The data I based my assumptions on comes from web sources. The British solar Energy society has a map of Britain with contours on it. These contours were for annual solar radiation on a square meter facing south at 30degrees to the horizontal.From that map most of Scotland gets about 800 kilowatt hours per annum per square meter. One might think that the figure should be multiplied by the cosine of 30 degrees, but the extra radiation in the early morning and late evening during the summer months offsets this a bit. Whilst solar energy levels are about 800 kwh, hours of sunshine are higher at about 1400 per annum.
Reply | Report Abuse | Link to thisIndoor agriculture has an urgency arising from other sources.Outdoor agriculture uses far more fresh water because much is evaporated away into the atmosphere and effectively lost. The trend over the last half century to increase the scale of monocultures of both crops and livestock, has been sustainable because chemical and pharmaceutical companies have been able to keep ahead of ability of pests and diseases to mutate resistant mutations. Paradoxically large concentrations of single species and the deployment of chemical defencies increases selection in favour of malign mutations in the attacking organisms. It is an arms race with no certainty that we will always win. Physical barriers and isolation will give us more defence against this relentless attack. Thirty years ago the idea that cows could be milked robotically was considered far fetched by most, yet an increasing number now are, and I reckon within twenty years more than half the milk production will be by robots. The reasons are surprisingly simple. A cow is naturally suckled by a calf several times a day and that way she not only gives more milk, but milk of higher quality, and she is less stressed by a painfully full udder. Manually milked cows seldom get milked more than three times a day, and it is expensive to staff round the clock milking. A milking booth will in future incorporate up to date diagnostic technology, so that the cow's health is better monitored than ever before. Similar applications of electronics and robotics will allow intercropping of compatible crops in growth houses to maximise production and quality, whilst minimising the risks attending outdoor crops. Isolation and dispersal will be a key strategy, so that if the biosecurity of one growth house is breached , only a limited amount of crop is affected.
bauserman1,
Reply | Report Abuse | Link to thisI fully agree that population must be reduced......You go first.....
While I would not dispute that crop production can be done in a building (I'm currently harvesting lettuce from a few pots in a south-facing window), I'm skeptical of this being done in an economic manner. Before proceeding with more thought experiments on the feasibility of doing this, it would be good to actually try it out and see just how much production is possible. I suspect there will be problems with low production because of short day length during the winter and depth of light penetration into the building because of high sun angle in the summer. Greenhouses are a proven technology, but greenhouses with opaque ceilings (that is, multi-story buildings) aren't. Perhaps we would get more benefit out of using the vast expanses of flat supermarket roofs for open air and greenhouse production of produce that could be sold on premises. It could also get part of its fertilizer requirements by composting the trimmings and spoiled produce that now gets sent to landfills.
Reply | Report Abuse | Link to thisWhile I would not dispute that crop production can be done in a building (I'm currently harvesting lettuce from a few pots in a south-facing window), I'm skeptical of this being done in an economic manner. Before proceeding with more thought experiments on the feasibility of doing this, it would be good to actually try it out and see just how much production is possible. I suspect there will be problems with low production because of short day length during the winter and depth of light penetration into the building because of high sun angle in the summer. Greenhouses are a proven technology, but greenhouses with opaque ceilings (that is, multi-story buildings) aren't. Perhaps we would get more benefit out of using the vast expanses of flat supermarket roofs for open air and greenhouse production of produce that could be sold on premises. It could also get part of its fertilizer requirements by composting the trimmings and spoiled produce that now gets sent to landfills.
Reply | Report Abuse | Link to thisOf note, the Eurofresh Farms mentioned in the article filed for Chapter 11 bankruptcy in April 2009 http://bit.ly/8ZCl8L . Most of the debt seems to be to investors. But of note are the trade and contract debts, gives a sense of dollars involved for harvesting, shipping, and power.
Reply | Report Abuse | Link to thisThe statement that"Growing food on land that used to be forests and prairies is killing the planet" is preposterous. Wheat and corn are grasses growing where prarie grasses once grew and are carbon "sinks" also. Native prarie has about 5% organic matter (the carbon "sink"). Tilled farmland will recuce that by one-half, where it stabalizes. No-till production of corn and wheat will eventually restore the organic matter to native levels. Modern farm methods are sustainable, contrary to the claims of non-agriculture activists/alarmists. And these days most nutrient polution comes from urban lawns and sewage.
Reply | Report Abuse | Link to thisThe mumbo jumbo of decade, a dead cert for IgNoble prize in economics.
Reply | Report Abuse | Link to this1) Plants need a lot of light to grow, in a vertical farm you just get a small fraction of sunlight needed, the rest must be artificial lighting making whole concept unrealistic, unless one day we discover an extremely cheap method of producing energy.
2) Land in cities is extremely expensive, unless one day people don't decide to live cities en masse, leaving behind plenty of empty buildings that no one will be willing to buy, it is totally unrealistic to think that about spending several millions $ for a small parcel just to grow a couple of hectares of potatoes there.
5) Plantations of vegetables like tomatoes or cucumbers use just an insignificant part of the land. Most of arable land is used for corn, wheat, soya that are not directly consumed by people, but by animals grown for meat, or now more and more for production of bio-fuel.
Obviously, it is pointless to plant corn for cows in N.Y.
4) All improvements mentioned by prof. Despommier which could improve yield and efficiency could be applied to standard one level greenhouses located in regions with poor soil quality (don't need soil for hydroponics), but where is a lot of sunshine and lot of rains.
5) If we want to save some remaining ecosystems from destruction (which we should do), the only solution is a drastic population control, at least as severe as in China. There is no way to save ecosystems, climate, and provide for everybody decent living conditions if we are 9 000 000 000.
I wonder if Scientific American reviewers are on strike ? It seems that no one with basic knowledge of plant photosynthesis reviewed this article. Good for prof. Despommier who after publication of his mumbo-jumbo in serious scientific review can more easily get some public money for his fancy idea....
What about following problems not mentioned in the article :
Reply | Report Abuse | Link to this1) Plants need a lot of light to grow, in a vertical farm you just get a small fraction of sunlight needed, the rest must be artificial lighting making whole concept unrealistic, unless one day we discover an extremely cheap method of producing energy.
2) Land in cities is extremely expensive, unless one day people don't decide to live cities en masse, leaving behind plenty of empty buildings that no one will be willing to buy, it is totally unrealistic to think that about spending several millions $ for a small parcel just to grow a couple of hectares of potatoes there.
5) Plantations of vegetables like tomatoes or cucumbers use just an insignificant part of the land. Most of arable land is used for corn, wheat, soya that are not directly consumed by people, but by animals grown for meat, or now more and more for production of bio-fuel.
Obviously, it is pointless to plant corn for cows in N.Y.
4) All improvements mentioned by prof. Despommier which could improve yield and efficiency could be applied to standard one level greenhouses located in regions with poor soil quality (don't need soil for hydroponics), but where is a lot of sunshine and lot of rains.
The world's population is projected to grow exponentially in the near future, raising concerns about feeding an expected 9.5 billion mouths by 2050. The food crisis of 2009 has already pushed one billion people into hunger (FAO, 2007). In an attempt to tackle the current food crisis, conventional agricultural methods are becoming ever more unsustainable with increased inputs of fertilizers and scarce water resources. Vertical farms are housed in skyscrapers and grow food in rigorously controlled conditions. They are among several technological solutions proposed to address the global food supply crisis. Dickson Despommier, a major proponent of vertical farming, advocates building vertical farms in major cities across the globe. His articles and op-eds on this subject have recently appeared in the New York Times and Scientific American. As a result of the attention being given to this potential solution to the global food crisis, vertical farms are now being considered by urban planners and policy-makers in New York, Chicago, Los Angeles, Dubai and many other urban areas. The authors of this article would like to raise a few questions about the economic and societal implications of this revolutionary idea.
Reply | Report Abuse | Link to thisThe concept of vertical farming developed as a radical answer to energy inefficient farming techniques, concerns about climate change, and the world's growing need for food. Vertical farms of the future will be located in large urban areas, reducing greenhouse gas emissions released during transportation, decreasing transport costs, and allowing overtaxed agricultural land to heal. Despite the urge to gratefully welcome any solution to feeding the hungry, which at the same time promises to help address the world's climate challenges, there are many problems inherent in the premise of vertical farming. Vertical farms require an inordinate amount of energy and water, not unlike conventional farming. Vertical farming also requires financial resources in order to buy up scarce property in an urban environment, build the capital intensive farm infrastructure, and maintain the farms. In light of these issues, how is it possible that vertical farms are being touted as an answer to the global food crisis? The enormous stock of financial and other resources needed for vertical farms is lacking where its most needed the developing world. Vertical farms are economically unfeasible in the areas of the world where population is projected to explode, and where, in the majority of cases, water resources are already stretched to their limit. The bottom line is that promoting urban sustainability through the development of vertical farms is not the answer to the world's growing need for food.
Rather than developing expensive, unrealistic, and technological solutions to the global food crisis, what about seeking answers from the earth itself? Despite Despommier's statement that "agriculture also uses 70% of the world's available freshwater for irrigation, rendering it unusable for drinking as a result of contamination with fertilizers, pesticides, herbicidies, and silt," the answer shouldn't be to turn to ever more technological, input-reliant methods of growing food. The answer should be to revolutionize the destructive, expensive, and wasteful practices of large scale conventional agriculture. If land is treated with more care, if sustainable agriculture is practiced globally, and if trade subsidies are abolished on agricultural products from countries with rich soil, the authors believe that land currently under agricultural development would indeed produce enough food for everyone. Local farmers could feed their communities, surplus crops from certain regions could be traded to regions suffering from drought, and local economies would grow stronger; promoting cohesive societies and better nourished individuals. On top of these economic and social benefits, the land we live on would eventually become healthier and more productive.
Not only do vertical farms present a fairy tale answer to feeding urban poor and those globally suffering from undernourishment, but they threaten to diminish the already stressed relationships between people and place that contribute to healthy societies and communities. Much has been written on the effects of urbanization on mental health and psychological well being. Much has also been written and discussed on the importance of a connection to one's neighbors and a connection to the land one lives on to human happiness and well-being. 83.5% of the world's population is projected to be living in urban areas by 2050 (United Nations, 2000). While there is nothing immoral or inherently bad about life in urban areas, what kind of future are we looking forward to if the majority of humans will have a decreasing connection to the land they live on, the farmers who grow their food, or the sense of community that gives meaning to life and a feeling of belonging? Building vertical farms promotes urbanization. Vertical farms propose to feed the growing ranks of urban dwellers from within the bounds of each metropolis. In the developing world, where vertical farms are financially feasible and where more and more people suffer from depression and feelings of loneliness, how can vertical farms really contribute to a better society? More urbanization will only worsen the societal ills which plague many parts of the "developed" world. Happiness and well-being can be fostered by efforts at relocalization, promotion of farmers markets and community-supported agriculture, and revitalization of local farms and local economies.
We applaud any efforts to eat locally, to decrease emissions from the transport of food goods, and to make use of urban gardening techniques. Rooftop gardens, "vertical gardens" on vines on your balcony, and city gardens in abandoned lots are all approaches to growing food in an urban environment that promote collaboration, a sense of community, a sense of place, and a sustainable urban life. We are not fundamentally opposed to the concept of vertical urban farming, but strongly disagree with the belief that this can be a solution to feeding the unfed, or meeting the growing nutritional need of the urban impoverished. We also believe that such technological solutions to basic human needs should be approached with caution, with consideration for societal implications, and only when combined with efforts at revitalizing small scale farming and relocalization of food systems in rural and semi-rural areas. Is it unrealistic to expect conventional methods of agriculture to be replaced by sustainable, locally-based farming? Yes. But rather than channeling our intellectual, financial, and technological resources to develop a concept like vertical farming that can only lead to further breakdown of human connections and a sense of place, we should channel those efforts and resources to fixing what we already have, taking care of our natural resources, and building a more cohesive human community. Currently in press, Despomeirs new book on vertical farms is called Vertical Farm: The Big Idea That Could Solve The Worlds Food, Water and Energy Crises. With the economic and societal implications of vertical farms, we are left wondering - whats the big idea?
The world's population is projected to grow exponentially in the near future, raising concerns about feeding an expected 9.5 billion mouths by 2050. The food crisis of 2009 has already pushed one billion people into hunger (FAO, 2007). In an attempt to tackle the current food crisis, conventional agricultural methods are becoming ever more unsustainable with increased inputs of fertilizers and scarce water resources. Vertical farms are housed in skyscrapers and grow food in rigorously controlled conditions. They are among several technological solutions proposed to address the global food supply crisis. Dickson Despommier, a major proponent of vertical farming, advocates building vertical farms in major cities across the globe. His articles and op-eds on this subject have recently appeared in the New York Times and Scientific American. As a result of the attention being given to this potential solution to the global food crisis, vertical farms are now being considered by urban planners and policy-makers in New York, Chicago, Los Angeles, Dubai and many other urban areas. The authors of this article would like to raise a few questions about the economic and societal implications of this revolutionary idea.
Reply | Report Abuse | Link to thisThe concept of vertical farming developed as a radical answer to energy inefficient farming techniques, concerns about climate change, and the world's growing need for food. Vertical farms of the future will be located in large urban areas, reducing greenhouse gas emissions released during transportation, decreasing transport costs, and allowing overtaxed agricultural land to heal. Despite the urge to gratefully welcome any solution to feeding the hungry, which at the same time promises to help address the world's climate challenges, there are many problems inherent in the premise of vertical farming. Vertical farms require an inordinate amount of energy and water, not unlike conventional farming. Vertical farming also requires financial resources in order to buy up scarce property in an urban environment, build the capital intensive farm infrastructure, and maintain the farms. In light of these issues, how is it possible that vertical farms are being touted as an answer to the global food crisis? The enormous stock of financial and other resources needed for vertical farms is lacking where its most needed – the developing world. Vertical farms are economically unfeasible in the areas of the world where population is projected to explode, and where, in the majority of cases, water resources are already stretched to their limit. The bottom line is that promoting urban sustainability through the development of vertical farms is not the answer to the world's growing need for food.
Rather than developing expensive, unrealistic, and technological solutions to the global food crisis, what about seeking answers from the earth itself? Despite Despommier's statement that "agriculture also uses 70% of the world's available freshwater for irrigation, rendering it unusable for drinking as a result of contamination with fertilizers, pesticides, herbicidies, and silt," the answer shouldn't be to turn to ever more technological, input-reliant methods of growing food. The answer should be to revolutionize the destructive, expensive, and wasteful practices of large scale conventional agriculture. If land is treated with more care, if sustainable agriculture is practiced globally, and if trade subsidies are abolished on agricultural products from countries with rich soil, the authors believe that land currently under agricultural development would indeed produce enough food for everyone. Local farmers could feed their communities, surplus crops from certain regions could be traded to regions suffering from drought, and local economies would grow stronger; promoting cohesive societies and better nourished individuals. On top of these economic and social benefits, the land we live on would eventually become healthier and more productive.
Not only do vertical farms present a fairy tale answer to feeding urban poor and those globally suffering from undernourishment, but they threaten to diminish the already stressed relationships between people and place that contribute to healthy societies and communities. Much has been written on the effects of urbanization on mental health and psychological well being. Much has also been written and discussed on the importance of a connection to one's neighbors and a connection to the land one lives on to human happiness and well-being. 83.5% of the world's population is projected to be living in urban areas by 2050 (United Nations, 2000). While there is nothing immoral or inherently bad about life in urban areas, what kind of future are we looking forward to if the majority of humans will have a decreasing connection to the land they live on, the farmers who grow their food, or the sense of community that gives meaning to life and a feeling of belonging? Building vertical farms promotes urbanization. Vertical farms propose to feed the growing ranks of urban dwellers from within the bounds of each metropolis. In the developing world, where vertical farms are financially feasible and where more and more people suffer from depression and feelings of loneliness, how can vertical farms really contribute to a better society? More urbanization will only worsen the societal ills which plague many parts of the "developed" world. Happiness and well-being can be fostered by efforts at relocalization, promotion of farmers markets and community-supported agriculture, and revitalization of local farms and local economies.
We applaud any efforts to eat locally, to decrease emissions from the transport of food goods, and to make use of urban gardening techniques. Rooftop gardens, "vertical gardens" on vines on your balcony, and city gardens in abandoned lots are all approaches to growing food in an urban environment that promote collaboration, a sense of community, a sense of place, and a sustainable urban life. We are not fundamentally opposed to the concept of vertical urban farming, but strongly disagree with the belief that this can be a solution to feeding the unfed, or meeting the growing nutritional need of the urban impoverished. We also believe that such technological solutions to basic human needs should be approached with caution, with consideration for societal implications, and only when combined with efforts at revitalizing small scale farming and relocalization of food systems in rural and semi-rural areas. Is it unrealistic to expect conventional methods of agriculture to be replaced by sustainable, locally-based farming? Yes. But rather than channeling our intellectual, financial, and technological resources to develop a concept like vertical farming that can only lead to further breakdown of human connections and a sense of place, we should channel those efforts and resources to fixing what we already have, taking care of our natural resources, and building a more cohesive human community. Currently in press, Despomeir’s new book on vertical farms is called Vertical Farm: The Big Idea That Could Solve The World’s Food, Water and Energy Crises. With the economic and societal implications of vertical farms, we are left wondering - what’s the big idea?
The first thing that struck me was the salesmanship of Mr. Despommier. The lovely "green" letters and all the "green" veggies, as they say one picture is worth a thousand words. The problem is that anyone who reads even a little will see the flaws in this idea by all of it's "assumptions". The main one is that "Farming is ruining the environment", one of the Key concepts of his. It is more likely the WAY we produce things in general is the main culprit. We "overproduce" everything and in record time by unnatural chemicals (as the pictures so nicely show), but these same chemicals would still be in use. The wastewater that he proposes to be used could just as easily be used now in traditional farming. I take issue with the fact that these high rises would cost an enormous amount of money which only a few leading producers would/could afford and then our food supply would be in the hands of a few which could be extremely dangerous to the population as a whole....who decides, who gets to eat and at what price?
Reply | Report Abuse | Link to thisThe other issue is this overpopulation that keeps getting exploited for political and economical purposes. The Mathus model of ANY population is a mathematical equation that doesn't really reflect the true population of the world. First it doesn't take into account the fact that in Nigeria and other abundant populous places the children who do get born often don't make it to the age of five and the parents don't live past the age of 44 the population sample isn't the same for all areas of the world. The same goes for resources, the assumption that the whole world uses the same amount of resources is ludicrous. I like the idea of green house but it needs to be refined so that it truly does benefit the WHOLE world not just the select few. The ones who propose these more efficient models of food production are the very same ones who use overpopulation as an excuse for their products. More food production means food for the "overpopulated" areas as well...will they be a part of this technology improvement? If so how does that help population control?
An after thought...did anyone besides me notice these structures resemble the Taipei 101.....tangent thought....stock market also very "green". LOL
Reply | Report Abuse | Link to thisTo those who think this is such a nonsensical idea, why don't you try coming up with a better solution. There's no sense in being a typical blogger, commenting on serious matters by trying to find every flaw and loophole in a story. How is that productive?
Reply | Report Abuse | Link to thisTo those who think this is such a nonsensical idea, why don't you try coming up with a better solution. There's no sense in being a typical blogger, commenting on serious matters by trying to find every flaw and loophole in a story. How is that productive?
Reply | Report Abuse | Link to thisHi vrrh - How's this for a practical solution. More than forty years ago holding up the canopy of a growth house by simply increasing the internal pressure by a few millibars was successfully demonstrated. Thus quite large areas can be covered and protected from both the weather and pests and diseases. The water that plants give off whilst photosynthesising can be condensed out of the internal atmosphere for recycling, along with the drainage water. thus the main problems of crop production are solved and productivity raised without increased pollution.If hydroponics are used as the groth medium, then these installations can be sited on poor land with little loss of productivity. Only about 45% of the solar spectrum is used for plant growth, so photovoltaic cells embedded in the canopy and working on other parts of the spectrum could provide the power for the systems and maybe some extra. A marine equivalent would be transparent tubes floating near the surface producing algae and phytoplankton to feed a food chain ending in commercially attractive species. Protecting these tubes and fish farms from the weather and marine predators might require wave energy devices and robust electrical fence nets. The problem with food is not whether it can be produced, or not, but that unregulated markets often force the price too low. What people expect to get cheap they generally use wastefully. Cheap food is not the answer to poverty, and it probably never was.
Reply | Report Abuse | Link to this"How would you go about reducing the population?"
Reply | Report Abuse | Link to thisUnleashing a virus to cripple peoples reproductive systems. If people are too animalistic to exercise self control, and avoid breeding the species to death, then the problem will be remedied by those in the position to do so.
It's all bogus until someone builds one and does the financial analysis. Turns out one company has: Valcent Products has crunched the numbers and their VertiCrop system is now ready to go global with the help of their new director R F Kennedy Jr.
Reply | Report Abuse | Link to thisGoogle VertiCrop and you'll see that vertical farming is here today.
Just off the top of my head and I know it's not popular in a "green" society, but what about using nuclear power to overcome the energy requirements? I am not an expert or anything and t is a limited resource to be sure, but it could be used until technology improves for solar power to be more viable. If you use a nuclear plant as a the central power source for a hub of these vertical farms, it may help keep the cost for energy down a bit. (Though there are plenty of other issues to deal with as well.)
Reply | Report Abuse | Link to thisAnother idea, this time for lighting (since I didn't see it mentioned earlier), is to develop a mirror system that can be used to direct light to the areas that need it most. Also, if you have a diverse crop selection, your outer edges of the VF can be for the ones that need the most light and the inner area for those that need less. You can then use the mirros to funnel the light as needed.
Reply | Report Abuse | Link to thisI am not actually convinced a skyscrapper is the best structure, I was thinking more along the lines of a stadium (or an upside down pyramid) type situation where you can put a second pyramid of mirrors in the central bowl to redirect light. This would give a good amount of light on both the outer and inner edges of the stadium without too much cost associated with it. I also think the tiered system would work better for arranging, watering, and harvesting the plants.
By the way, these are pie-in-the-sky ideas without any supporting numbers of scientific theory. Just ideas that may get around some of the very real and very siginificant limitations of these types of farms.
By having less children over the next 30 years or so.
Reply | Report Abuse | Link to thisTeaching Birth Control and Family and economical planification. Having less children over the next 30 or 50 years will solve the population problem.
Reply | Report Abuse | Link to thisSilverFng: I've seen a number of proposals for VFs that use mirrors; unfortunately, mirrors do nothing to overcome the inherent problems with VF as outlined in many of the comments here.
Reply | Report Abuse | Link to thisTo reiterate: crops are a means to convert inedible solar energy to edible biomass. The most efficient crops (staples such as wheat, corn, rice, etc) will require full sunlight, not shade, and will convert something less than 10% of the solar energy they receive to edible calories. For a building of any shape, the amount of sunlight available to it is about the same as the amount of sunlight that would fall on the land the building occupies. The height of the building can't increase this. Mirrors can only move light from one place to another--a VF with five stacked floors of one acre each, for example, will receive 1 acre worth of sun on the roof, but lighting each floor with reflected light will require an acre of mirrors per floor placed somewhere else, so that the VF will still occupy 5 acres of surface area. Your stadium scheme has the same problem--the central bowl occupied by mirrors is then unavailable for planting.
Still unanswered, some seven months later: why did Sci-Am publish a cheerleading article on VF by someone with no background in horticulture, agriculture, engineering, physics urban planning, or architecture, who has had no peer-reviewed publications on the subject, and whose sole "research" seems to consist of assigning a few seminar projects in VF to undergraduates and a few graduate students? And why has Sci-Am made no attempt to fact-check or respond to the obvious holes in Despommier's VF evangelism?
Hi David - I haven't looked at this thread for wee while now, but you have comprehensively demolished the suggestions of using mirrors. Let's face it Mr Despommier's stance is largely based on highly warped view of agriculture and it's alleged impacts on the environment.
Reply | Report Abuse | Link to thisLike you I am depressed that SA seems to be dumbing down and putting whow factor above scientific credibility and peer acknowledgement. As they are making this article part of a feature "Urban Visions:Cities of 2030" , without any
qualification on the part of the editors about the fantasy claims made by Mr Despommier, one can conclude that they either believe him ( which says volumes about their own scientific abilities ) or are too embarrassed to disown him ( which puts their integrity at risk ).
I have asked them from time to time to get someone to write a credible article on the pro's and cons of evacuated tube transport, but to no avail. This development has the potential to make medium and long distance transport genuinely faster and less damaging to the environment than what is presently available.
How come Fiber optics couldn't be used to solve the issue ?
Reply | Report Abuse | Link to thisThe tendency to think that this kind of evolution of agriculture has to happen on a grand scale 30 stories high for a cost of tens to hundreds of millions of dollors per project is simply a perpetuation of the corporate Ag model. There may be a niche for this kind of project, but the economy of scale may point to a smaller, more distributed and organic model.
Reply | Report Abuse | Link to thisI am an agricultural engineer specialized in Greenhouse environments.
Reply | Report Abuse | Link to thisFirst let's debunk a few myths:
In the same way than mirrors can only bring or redirect light from somewhere else, fiber optic has the same limitation plus the fact that even with the best material available the transmission of light through glass incurs a loss of about 1% per in. So by the time you have a fiber optic string a few hundred feet long, you will only have a negligible amount of energy left to grow stuff (basicaly, what is acceptable for data transmission is not for energy transmission).
Second one of the Despommier assumption about the yields of some crops is correct. In the case of tomatoes for example it is commonly recognised that 1ac of greenhouses can replace up to 40ac of field tomatoes. That figure includes the fact that the greenhouse tomatoes will be producing more with significantly less water and fertilizer(recyculating system).
Now, let's be clear that tomatoes (and most greenhouse crops) are luxury crops that will never feed the poor, but in urban setting could have the positive impact to bring year-round stable jobs.
Vertical farming as presented by Despommier is a boondoggle of epic proportions, urban agriculture OTOH is not.
This article is pretty far-fetched to say the least and I see no evidence of the rigour that I would expect of a publication like Scientific American. I strongly recommend you read George Montbiot's article on the subject (see link below).
Reply | Report Abuse | Link to thishttp://www.monbiot.com/archives/2010/08/16/towering-lunacy/
Total bunk. Vertical farms are totally unsustainable. The world can produce plenty of food to sustain the current population. We waste as much as 50% of everything that is produced, because we don't know how to store properly, market properly and pay properly for the production. If more was paid for good quality food at the farm level, farming would be able to find all sorts of sustainable solutions to feed the world. The world looses farming expertise every day because of the poor returns. The problem will be more of who can grow our food than where we grow it.
Reply | Report Abuse | Link to thisPopulation in 2050 going to increase 1.4 time more than now. Can't we increase production 1.4 time more than now? I think yes, we can increase, than we don't need this very expensive vertical building.I is very good idea, but it should be only 2 floor: 1st floor for supplying and 2nd floor for growing which use sunlight, which is free. 20 years working with same project, I did find "new plant nutrition system", which allows increase productivity of any plant more than 5 time. I believe could be someone find a way to increase productivity maybe more than 5 time too and it is possible increase productivity more than 10 time. So, don't worry about increasing population, we can increase production much faster than population will increase.
Reply | Report Abuse | Link to thisLets get all the non-profit food suppliers together and build a Vertical Farm.
Reply | Report Abuse | Link to thisThe fed funding is being slashed drastically under Obama.
Its an emergency to get this going now.
It will create jobs, have a zero carbon footprint, all organic, no GMO's.Uses 5% of what traditional farms require with zero pesticides or chemicals.Its a win win situation for everyone.VERTICAL FARMS ARE THE WAVE OF THE FUTURE.
In India 40% of food production is spoiled before it reaches the consumers, By creating HOPP Horticultural Operation Production Plants within urban areas it is possible to reduce the waste. If we can reduce the waste with 50% it is possible to feed over 200 million people by the sheer waste reduction. Vertical Farming brings food in those areas where needed and avoids spoilage due to transport and time lost in warehousing and storage. By rethinking the procurement process within the food industry it will not only reduce the production costs substantially but also feed more people Why waiting?
Reply | Report Abuse | Link to thisIf you want to join the thoughtproces please join the vertical farming (hopp) on linkedin and share your thoughts and ideas.
http://www.linkedin.com/groups/Vertical-Farming-HOPP-Horticultural-Operations-4714478?trk=myg_ugrp_ovr
A few observations from the comments:
Reply | Report Abuse | Link to thisThere are too many people in the world!
Poppycock ... http://persquaremile.com/2011/01/18/if-the-worlds-population-lived-in-one-city/
We don't grow enough food!
From http://www.wfp.org/hunger/faqs "1 - Is there a food shortage in the world? Answer: There is enough food in the world today for everyone to have the nourishment necessary for a healthy and productive life."
And farming is ruining the environment? What non-sense. If you really want to "save the planet" maybe you could trade in your car, your stereo and your iphone for an ox cart, a drum, and two juice cans with a string and then we will talk.
Your concerns about energy inputs required in the vertical garden as presented are warranted. Let me propose a few tweaks on the subject:
Reply | Report Abuse | Link to thisLine the outer edge of the high rise section of a city center with these vertical farms. Consider configuring the high rises with terraced floors each with east, west and a long south facing walls sloped at the angle complementary to the location's latitude (ziggurat anyone?). The long axis of the building would be orthogonal to the south (Northern Hemisphere). The height of the space between each floor would then determine how much floor space would be usable for the aquaponics plant beds. This would eliminate the need for most of the grid power need for plant growth. Also, following the lead with Local Food providers, grow plants "in season" for the season. These plants are already adapted to the amount of sunlight available at that time of year. Photovoltaic Solar panels on the roof would also provide for more solar input. North of the greenhouse space would be the desirably darker space for fish tanks. North of that on each floor would be room available for retail including a green grocer on the first floor, restaurants consuming the product of the gardens and fisheries. Offices and living space placed on higher floors.
The building would also provide tertiary treatment for gray water from the building tenants and water treated partially already from the sewage treatment facility nearby. The intriguing aspect to using transpired water from the plants condensed using geothermal heat sinks for potable water closes the loop on a contained water cycle. Obtaining clean water from wild sources is already problematic for many parts of this country experiencing drought.
Do not forget the savings in fuel currently needed to bring fresh produce from the south or west of the country. There would be additional social benefit in the jobs available to semi-skilled workers tending each floor. I look forward to your quantitative analysis of such a proposal.