The City As Ecology

Sustainable Civilization: From the Grass Roots Up
Chapter VII - The City As Ecology - 2
What is the minimum population that is a large and dense enough gathering of people to provide the opportunity for continued training in specializations? How many times was fire discovered, or the wheel, or the beginning principles of math, only to be lost when the individual with the spark of insight died? 
Civilization exists to protect voluntary safe interaction among individuals. 
There must be ease of interaction, not only in exchange of information, but of goods and services. For non-crash consideration of the infrastructure aspects, examine on the web the publications of the “New Urbanism” movement.
Taking a long term view, in a low energy paradigm, the city needs to be an ecosystem where its living and non-living aspects have multiple and interwoven sources of feedback. 
The combined skills of technologists, economists, and ecologists are needed. A back-to-nature approach will not work - there are too many of us for that.
- Eric A. Davidson, You Can't Eat GNP
PURPOSE
To provide on a local basis life support and sustainable community, including not merely the ability to repair existing technology and maintain current knowledge and skills, but to continue to advance. As an element of a larger civilization, each city can be seen as potentially the provider of a unique product or service specialty.
"A city's internal transportation system - the layout of its streets and roads, the layout of streetcar systems and subways - determines the character of the city, how its citizens live and work. It has less to do with the direct engines of wealth creation. Build subways and people will live in dense neighborhoods and walk to corner stores; build broad suburban streets and they will live in subdivisions and drive to the Wal-Mart." -Alex Marshall (How Cities Work)
"Above all else, a city is a means of providing a maximum number of social contacts and satisfactions. When the open spaces gape too widely, and the dispersal is too constant, the people lack a stage for their activities and the drama of their daily life lacks sharp focus." -Lewis Mumford (The Highway and the City)
"City-making is an art rather than a product of statistical analysis or social service casework."
"The future will compel us to change our way of life, to give up the fiasco of suburbia and all its revolting accessories and re-condense our living and working places into the traditional human habitats called cities, towns, and neighborhoods." -James Howard Kunstler (The City In Mind)
MINIMUM SIZE
Preserving civilization on the scale of an "ecovillage" is probably not sufficient to maintain even present knowledge, skills, and technology, let alone make significant advances. Similar to a single family retreat (homestead), or a multi family (6 min 20 suggested) retreat (Homestead associations), an ecovillage can be too small to maintain "civilization", yet it is already too large to be an ad-hoc creation.
Education factor. Just providing on a sustainable basis teachers for K - 12 requires something larger. In Ecovillage discussed earlier we assumed each grade 1 to 12 classroom has 20 students, with each village unit requiring 72 teachers. 
If each teacher works an average of 36 years, then for 72 teachers on the average two retire and must be replaced each year. If college for a teacher takes 4 years, with 20 teachers per college class, there are 80 teachers minimum "in the pipeline" at any given time, with 20 minimum graduating each year. An individual ecovillage only needs only 2 though.
To utilize the minimum efficient production of any given teacher specialist requires at least 10 ecovillages or a population of 96,000. If you want for example 8 different "specialists" in teachers, the number of ecovillages needed to provide for teaching the teachers jumps to 80, or a population of 768,000.
HUMAN SCALE
Los Angeles, New York, etc., are not likely candidates for conversion to low energy, low population sustainability. Such cities, that combine over dense population with sprawl will not survive a fossil fuel shortage, for example they cannot produce sufficient food within their borders. 
Cities as we know them have exceeded the law of diminishing returns and become a gathering place for the excess and excesses of humanity. 
Human scale clearly implies the ability for an un-enhanced human to access the services available within a reasonable amount of time and with a reasonable amount of effort. (Not necessarily “immediately”.) 
RETROFIT
While some cities may be too large, on the other end of the discussion, how do you see a large enough group coming together to start a city-scale eco-community from scratch? There may though be existing communities, with plot division, roads, pipes, wiring, etc. already in place that could be steered into a path to develop along more sustainable lines.
What, to you, is "Human scale"? How far are you willing to walk to visit family or friends, the library or museum? How far to grow or purchase your food? How far to your employment?
Commuting distance. Absent "energy to burn", the upper size is the ability to get people and supplies around. 
I would suggest that an "optimum" size is one where homes are within a reasonable bicycle ride of the city center minimizing "need", or demand for motorized intracity personal vehicles. (Per the average of several bicycle safety sites, expect "sustained" speeds of 12 (experienced), 8 (average adult) and 6 (very young or very old) mph for a human on a typical upright bicycle. When younger, I recall almost daily bike rides from downtown Seattle to the mall, a one-way trip of about 12 miles…) A half-hour commute (reasonable?) to the city / industrial core should probably be no more than 4 to 6 miles or so from the most distant housing.
Let's carve out an arbitrary 9 square miles of city core, as a mile wide cross in the center. For the outer edge to be 6 miles from the far edge of the perpendicular aspect of the cross (75% of the city center) the city overall is 11 mile wide. 
This provides 112 square mile "village" areas, at around 9,600 people each, or a city population of a little over 1 million. 
Potable water collection. Using earlier numbers developed for the homestead at 12" annual rainfall, to provide for human use, and biointensive gardening on the homesteads , the water collection area is around 230 square miles, a dedicated water collection belt around 3.5 miles wide would provide for filling the city cisterns. The city is now 18 miles on a side. 
Thinking in term of this same 230 square mile water collection area completely covered in present technology solar panels. This is around 712 million square yards constantly intercepting 712 million kw of sunlight. With 10% efficient solar panels while exposed to the sun it produces just over 71,000 megawatt of power. 
Tossing more numbers, 6 hour/day average, 360 (Ariziona) relatively clear days, 10% intermittent coverage, annually the array produces around 138 million megawatthour of power. Before we get too cheerful on this, note that the present cost for around 712,000,000 one-hundred watt solar panels at $500 each would be around $356 Billion, with each of the 134,400 homesteads in the city being billed abour $2.5 Million. 
Farming and food shipment. The city needs food. While each homestead has its own garden, the field inside each 20 homestead unit, adding the additional safety factor of farmland bordering the city for a population of a million, at 1/4 acre per person, requires say 390 square miles of farmland. As a belt outside the potable water collection, this would be a belt about 4.5 miles thick. The city is now 27 miles on a side. This puts the outer edge of the farming belt about 13.5 miles from the city center, and of course less for the housing areas, and most of the community centers of the villages. Not an unreasonable distance for even pedal-powered food shipment, if that's what is necessary. 
Crop irrigation water collection. Depending on the rainfall of the applicable area, the water collection area outside the farming area will vary. A 12" rainfall could for example require 6 times as much water collection as is planted in traditional farming. The farm water collection belt is 14 miles wide. The city is now 55 miles on a side.
Age Distribution. Assume a healthy population at essentially some stable total population. Assume on the average that the lifespan is around 80 years. Assume that on the average there are the same number of people in each particular age. In a city of a million or so, there are around 12,500 of each age.
The entire city need not be constructed or altered at the same time.
Just as a thought, curved roads, or those with tree planted "traffic circles" at intersections provide a visual limit helping to provide a feeling of place, rather than a straight line running off to the limit of vision. You must keep in mind though, that a curved road 
Consider three dimensional use of the space. Living space does not necessarily have to be at ground level. Say a big department store type building is 75,000 square feet. If built well, six homesites could be located on each such roof, while still leaving skylights to the business area below. What about the "roof" of your home as a greenhouse?
ECOLOGY
It seems clear that a human optimized ecology is incompatible with a "natural" ecology. I'm not thrilled about jackrabbits in my garden, rattlers napping on the porch, or stepping on scorpions as I enter a dark room, but they're part of the "natural" ecosystem. And we as humans want to exclude them.
Which would you think is a better house pet, an angora cat, or a captured bobcat kitten? We can, and need, to live in a self-regulating ecosystem, BUT it needs to be "domesticated" flora and fauna. We can reemphasize "biological" means of meeting our needs, obtaining materials, etc., but we've already over-run enough of "nature".
An ecocity needs to provide it's own food resources. Consider, a hunter-gatherer in a good area may need a square mile per person. For a population of 1 million, you're spread over an area 1000 miles on a side. That's not likely to support a high-tech civilization. High population density appears a civilization prerequisite. High density, indeed simple high numbers of humans, requires a deliberately organized food web.
 
It appears clear that making changes such that some city scale communities survive the crash is a requirement for maintaining civilization. The further we fall, the more knowledge, skills, and technology we are likely to lose. The further we fall, the harder it will be to regain ground. Fossil fuels have allowed us to make great advancements - let's not lose the achievements and waste the expended fuel, human creativity, and lives.
In a post fossil fuel era, I don't see how large scale long distance surface freight or travel is practical, nor is the extensive personal motor vehicle use of today. A city will encounter limits in sustainable population, most significantly in food and water.
As sprawl and suburbia (as we now know them) become impractical, the scale will need to be more "human" in terms of commute for regular daily activities (work, school, shopping, etc.) It doesn't mean that we have to lose civilization.
The infrastructure of human communities can be a unique ecology tailored not only our physical needs, but to our individual and collective aspirations. Properly developed, the need for external input for "life support", other than the sun, and occasional rain, can be minimized and essentially eliminated.
THE CITY AS ECOSYSTEM
An ecosystem consists of abiotic and biotic factors that vary in function, in location and time, which interacting with each other eventually reach relatively stable numbers and relationships. In a city as in an ecosystem, the early stages are occupied by pioneers who cope with the pre-existing conditions. As time passes, human presence and deliberate actions suppress “undesired” biotic factors in the community (i.e. insects, rodents, scorpions) considered as pests, or those that compete with humans for resources. Humans also alter physical abiotic aspects, and introduce and provide enhanced supportive physical environments for desired creatures. 
Ecologically the focus of a city is a population humans living in a definite area. The dynamics of human population density, age distribution, overall size, resource use and paradigms affects dramatically other creatures. In theory interactions of abiotic and biotic and selected human intervention should leads to a human centered mature climax community. Perhaps for example humans tend to intervene too much in factors affecting their biotic neighbors. 
In Biomimicry, Janie M. Benyus presents 10 "Lessons" humans need to learn, not only as individuals but as a civilization. Perhaps we should keep them in mind as we consider how we need to re-think and re-engineer already disturbed areas to better meet human needs while essentially eliminating the impact of human activities outside of human communities. 
Can we learn to:
1. Use waste as a resource.
2. Diversify and cooperate to fully use the habitat.
3. Gather and use energy efficiently
4. Optimize rather than maximize
5. Use materials sparingly
6. Don't foul their nests
7. Don't draw down resources
8. Remain in balance with the biosphere
9. Run on information
10. Shop locally
1. In general in an ecosystem the nutrient cycle is closed, but the weblike physical infrastructure and food chain allow high diversity and density. The human community seen as an essentially closed ecosystem must take steps to eliminate the concept of waste, with everything going back into the web as a resource. Considering the biological matter and water that have and continue to flow into the city, one might expect it to be a lush oasis. Instead for the most part we continue to have a one-way flow where materials enter the city only long enough to become trash, to then be shipped away. The world is full such that we cannot expect to indefinitely draw resources from somewhere else, and dump our effluent in the home of someone else. When it becomes clear that it is in your best interest, what steps will you take to:
- Cease "waste" enabling activity
- Utilize graywater and blackwater
- Compost biological scraps
- Pass on useful but no longer desired items
- Disassemble broken complex items for parts reuse
- Leave no waste to dangerous to reuse
- Your thoughts?
We must rethink and rework our use of materials. The throwaway economy that has been evolving over the last half-century is itself headed for the junk heap of history.
Various studies indicate that modern industrial economies could (as an interim measure) function very effectively with a level of virgin raw material use as low as one tenth that of today. 
We need to recycle all materials. Modern society uses a LOT of steel, which tends to dwarf all other metals combined. In the United States, roughly 71 percent of all steel produced in 2003 was from scrap, leaving 29 percent to be produced from virgin ore. 
Steel recycling began to “work” with the advent of the electric arc furnace, a means to re-melt steel from scrap using only one third the energy of that required for virgin ore. 
With the appropriate policies, metal can be used and reused indefinitely. Mature industrial economies with stable populations will find it easier to get most of their steel from recycled scrap, simply because the amount of steel embedded in the economy is essentially fixed. Countries in the early stages of industrialization have little steel for recycling, and there is little enough raw material left.
Another recycling example is breaking down old buildings into their component parts so they can be recycled and reused. As with old-time efforts to deconstructing a barn or building, the same thought and care applied today can allow most of the material in a building to be recycled.
It SHOULD be a “no brainer” to design all products such as automobiles, appliances, and equipment so that they can be easily disassembled and their component parts recycled. Once “free” energy, and “free” raw materials are a thing of the past, linked with whomever wants to throw things “away” must pay for the long-term costs of such tossing, better design and reuse/recycling efforts will be in the best interest of business. 
Relatively recent governmental responses to encourage recycling is to ban various materials from garbage/landfills. What about simply eliminating the government involvement in trash collection completely? Make businesses, and individuals, find their own means to safely dispose of trash, if there is such, or otherwise avoid generating trash in the first place. The legislative involvement here is to simply protect general property rights, no one can legally dump on your site without permission, AND you cannot allow effluent from your site to be imposed on your neighbor. 
A refillable glass bottle used over and over requires about 10 percent as much energy per use as an aluminum can that is recycled. Cleaning, sterilizing, and relabeling a used bottle requires little energy, but recycling cans made from aluminum, which has a melting point of 660 degrees Celsius (1,220 degrees Fahrenheit), is an energy-intensive process. 
Even more fundamental than the design of products is the redesign of manufacturing processes to eliminate the discharge of pollutants 
entirely. Many of today’s manufacturing processes evolved at a time when the economy was much smaller and when the volume of pollutants was not overwhelming the ecosystem. More and more companies are now realizing that 
this cannot continue and some, such as Dupont, have adopted zero emissions as a goal.
“One man’s trash is another man’s treasure.” Simply put arrange industrial activity such that the waste from one process can be used as the raw material for another. (As it is in nature.)
2. Effectively fully use area and resources. Animals claim territory, yet do not show aggression to other species who claim the same territory, and cooperate with others of their species. 
- Niches for Decomposers, Scavengers & Miners
- Multi-Layer / Multi-Use
Animals and insects. They are part of an ecology, and can either BE pests, or used to control pests.
Commensalism - In commensalism, one organism derives benefits from its relationship with another. The other organism is not affected in any way by the relationship. 
Mutualism - In a mutualistic relationship, both participating organisms derive benefits from each other. This results in a steady, long relationship. Some may argue that this is the situation with human’s food animals, but a more likely example is human association with pets. 
The Ecological Niche of an organism describes how that particular individual "fits" into its ecosystem. Within its habitat, it must make use of available resources, withstand abitoic and biotic factors, with the help of adaptations. In other words, a niche is the role that the individual organism plays in its nonliving and living environment. 
Within a city the humans can clearly be seen as the top predator, with the typical animal “prey” of humans specifically nurtured in controlled environments for the purpose of becoming food. There are though those humans who physically prey on other humans, whether for physical/monetary gain, individual gratification, or just psychotic drive. 
In the world of unthinking plants and animals, a parasite usually physically lives upon or inside the host, with the host subjected to a long, painful relationship. Parasites and predators differ in that while prey suffers an almost instantaneous death, a host typically suffers prolonged pain, not necessarily leading to death. For e.g. – tapeworms. It remains similar at the human vs human level. 
Humans who impose on other humans as predators or parasites present a situation that may warrant intervention by physical or deadly force. 
3. Balance energy supply & demand: 
- Solar (Photovoltaic, heating, wind, hydroelectric, biomass)
- Geothermal
- Nuclear (Theory)
- Minimize regular movement of mass and people
- Minimize temperature extremes
4. Optimize rather than maximize
- More nutritious and greater variety and quantity of food for lesser numbers, vs a starvation diet for many
- Minimized energy needs vs toxic generation methods
- A productive thinking population vs a mass of uneducated welfare recipients
- Select annual crops for minimal residue
- Perennial crops are a standing investment
- Repair/Update vs Demolish and Build Anew
- Quality vs Quantity
There are limits on human population size, upper and lower, determined by factors such as resources and how they are utilized, knowledge and technology, and distribution and density of the population.
Concentrated populations are vulnerable to disease and environmental changes, but provide opportunity for accumulation of tools and knowledge, and the ability to readily exchange ideas. 
Dispersed populations are less likely to develop science and tools to deal with disease and environmental changes, or advanced technologies.
Each human generation represents a significant investment in time, physical resources, and education before the up and coming individuals are capable of self support, let alone producing any net individual advancement. (How long would it take a new adult to pay back the parents for the time and resources invested during their childhood?)
Within an ecosystem, including a city, larger environmental factors such as seasonal changes, rainfall, growing season, even decomposers and predators affect the cycle of resources, and therefore the overall stable population range. 
Even if life support factors are evenly distributed, at a more focused level, specialized environmental factors may require clustered populations. For humans, this could include potential daily factors such as work, school, and access to markets. 
5. Use materials sparingly
- Form fits function
- Use fits need
- Design for durability
- Think "Lending Library"
6. Don't foul nests
- No toxic releases
- Bioremediation
- Zero Fossil Fuel Burning
- No garbage dumps (Find a way to recycle, or stop producing the item)
- Avoid noise
Noise pollution – Can have physical consequences on the human body. We can reduce noise by producing less or, deadening it, or masking it with other "white noise". Earth sheltering, plants, avoiding hard straight surfaces, etc. helps greatly in noise abatement, but in general those “assaulted” with sound at harmful levels cannot completely mitigate the noise. Eliminating the sound of engines will do are great deal to bring a quiet to a city. Running and falling water, wind thru the trees, etc. are natural examples of white noise. Brushing up against someone in a crowd is different from a deliberate punch. Your right to swing your arm in YOUR space ends when it enters your NEIGHBOR’S space that happens to contain his nose. In a similar vein, those initiating noisy events or processes with harmful sound levels must realize the limit of their right. 
Considering toxic releases, the environmental effects of gold mining raises doubts about the net benefit to society. It involves extensive release of mercury and cyanide into the environment. To produce 2,500 tons requires the processing of 750 million tons of ore--second only to the 2.5 billion tons of ore processed to produce 1 billion tons of raw steel. The cleanup costs are left to someone else. To get an honest market price for gold means including the cost of cleaning up the mercury and cyanide pollution from mining plus the costs of landscape restoration in mining regions. 
7. Don't draw down resources
- Maintain groundwater levels and quality
- Don't Kill the "Golden Goose" 
8. Remain in balance with the biosphere
- Avoid population expansion incentives
Whether complementary proteins in human food, ph or other factors for plants, the supply of fresh water, etc., there are abiotic and biotic factors which limit any given population. This limiting factor can be too little, or too much of “something”. I.e. for humans there can clearly be too little or too much water. The range of tolerance though can vary dependent on many other factors, such as is there material to make rafts, or ability to store rare rainfalls. 
Within natural ecosystems, abiotic elements like nutrients are recycled and reused. Unfortunately most human communities have broken these natural cycles. 
9. Run on information
- Feedback on benefits and consequences
In nature, ecosystems self-organize based on feedback, some benign, some deadly. Humans must realize when we are selecting for improvement in the human community, and when we are acting to our own long-term detriment. 
Risk-taking has consequences. There are those who are lazy slobs. There are those who fill their bodies with dangerous substances. There are those subject to inherited illnesses and/or disabilities. 
An option for reducing the use of raw materials would be to eliminate subsidies that encourage their use. Whether the cost of irrigation water to farmers, paying farmer to NOT grow food, depletion credits to oil companies, etc. tax incentives seriously “skew” economic and therefore ecological decisions.
A growing policy is a proposed tax on the burning of fossil fuels. The tax is presented as a means that would reflect the full cost to society of mining coal and pumping oil, of the air pollution associated with their use, and of climate disruption. A carbon tax is claimed to lead to a more realistic energy price, one that will permeate the energy-intensive materials economy and reduce materials use. Obviously though, the tax revenues should NOT be used in any manner that creates a long-term dependency, as the indicated purpose of the tax is to discourage fossil fuel use. If the tax succeeds, then the revenue from the tax will be brief. 
10. Shop locally
- Import / Exports limited to luxuries
As the total mass of the human population has grown, instead of providing for greater, or faster recycling loops, and a more complex yet human centered ecosystem, we've broken feedback loops, destroyed much of nature, and isolated ourselves from the biology needed to sustain us. Considering the biological matter and water that have and continue to flow into the city, one might expect it to be a lush oasis. Instead for the most part we continue to have a one-way flow where materials enter the city only long enough to become trash, to then be shipped away. 
TECHNOLOGY
What are your thoughts for appropriate technology in a post fossil fuel era?
With liquid fuels a premium commodity.
With electricity in far more limited supply than today.
Long distance shipping (at least on land) inhibited by limited fuel and electricity.
Pedal Power. Certainly devices that are manually operated. Thinking… playfully… for a moment, can a computer be operated on the electricity generated by a pedal driven generator? 
What other pedal driven devices? A rule of thumb goes something like this: a human's peak power is 200W, and can sustain 50W to perhaps 75W for longer durations. Add a "buffer" (lead/acid battery and charge regulator) to smooth out the output, would there be enough to power a small desktop computer (Case + CRT), and even more so, a laptop (energy efficient Case + LCD screen).
Wind driven. Would you like an intermittent breeze in your home? Consider a direct driven inside fan, turned when the wind blows outside. 
Solar thermal. Relatively minor temperature differences can be used to circulate gas or liquids. The movement can be used to just move heat, or generate power. Solar can be used directly, or indirectly for cooking or heating. . 
Flat panel. 
Concentrating. In what technology other than solar can something as in-substantial as a sheet of shiny mylar be used to transform the diffuse warmth of the sun into a burning or melting tool capable of easily destroying the mylar performing the service? 
Biological. Early man started by “taming” those plants and animals that readily submitted. With genetics, we have far greater potential, and of course far greater RISK in what we can achieve. Drugs from bacteria, food or fuel from algae. Potentially custom designed species, or “to order” humans. 
Biogas. Biological waste, composted in a sealed container, can produce gas such as methane that can be collected in relatively simple water-traps, and used as fuel on demand. It is not readily efficient as fuel for motors, but it is a means to provide “stored heat” to cook in non-sunny periods, vs trying to store solar heat directly. 
Sewage processing in "living machines" to fertilizer (if not applied directly)
Wood. For all our "scientific progress", we ever managed to replicate this wonderful "chlorophyll" thing, just to make non-renewable, non-self-replicating, chemical imitations (photovoltaics).
Electronics. Components and simple devices, while perhaps not at energy efficient as present circuits, can be hand-made. CPUs (central processing units), the heart of any computer, is probably the most technically difficult thing to develop and build on this planet, together with "rocket science", building and launching rockets and satellites. A "fab" (short for fabrication facility, the huge white room places that build CPUs) costs billions of dollars to build, not including costs to operate, the research and development, all of this of course null and void once we no longer have enough oil to power tractors and the such, let alone for extravagant energy use like spending millions of barrels to find ways to cram up as many transistors as possible on a surface less than an inch wide. At what level of civilization and what type of technology, can computers be sustained?
Simple Devices. Electronic components can be made by simple technology, but the larger hand-made components use a great deal more power, and waste much of it has heat. 
A question: Does such a city have the technology and technique to repair or replace a broken plate or cup? A p/v panel? If each homestead has twenty five 100 volt panels, the collected homesteads of the city have 3,125,000 panels, with an expected lifespan of 30 years. 
A replacement schedule could then require production of around 100,000 panels per year. If p/v panels are broken, or fail on a regular basis, the city needs to produce or re-work 285 p/v panels every day. The Tucson MEC estimates that 8% of the p/v panels actually in use (2005) need to be replaced each year, which would be a daily replacement rate of around 685 panels. 
Is P/V, at least as we know it today, practical long-term? Can a city of a million do better?
Chapter VII - The City As Ecology - 2