January 23rd, 2010 by shrimppop

Overview

Recent discussions on The Oil Drum and elsewhere have thrown the question of sustainability into stark relief. What is sustainability? What makes one thing or system sustainable and another not so? Is there a framework or model for comparing relative sustainability? How do we measure and account for all aspects of sustainable systems?

Permaculture offers a set of specific approaches to these questions, although in some cases more detail is needed. For example, the need to perform “careful energy accounting” is recommended (if not required) without any real guidance as to how one would actually go about this. Holmgren and Mollison seem to agree that Howard Odum’s emergy approach to this issue is the best available tool, but even Holmgren admits to never having learned it.

My goal in this article is to sketch out some of the issues that play into a more comprehensive and detailed approach to sustainability, starting from Permaculture approaches with which I’m familiar.

Concepts in Sustainability

Systems Thinking

Much work on designing sustainable systems is based on a systems ecology foundation (Capra, Korten, Meadows, McDonough, Mollison, Odum and Barrett) of systems theory developed over the last century and a half by scientists such as Carnot, Clerk Maxwell, Wiener, Von Neumann, Von Bertalanffy, Forrester, Bateson and Prigogine. Systems theory includes concepts from thermodynamics. These include the difference between closed and open systems, how energy behaves in closed systems, and the fact that energy cannot be created but can be transformed.

Entropy is the measure of disorder in a system, and is always increasing overall in closed systems. When energy is transformed in a closed system, some energy is lost or degraded as heat, even when it is being transformed to a higher quality. Overall available energy in a closed system is always decreasing with time.

Howard Odum’s system of mapping energy flows through ecosystems shows how open natural systems transform low quality abundant solar energy into higher quality chemical and kinetic energy by “reinvesting” some of their stored energy in recapturing more low quality energy. Such transformations are measured by their transformity. Odum’s system also accounts for the embedded energy that went into creation of the system’s sub-components.

Lotka’s Maximum Power Principle posits that successful systems are those that accumulate and qualitatively transform energy most efficiently given some set of conditions. For example, old growth mixed forest is the “climax” ecological state in much of the Northeast, as this system maximizes efficient conversion of available energy.

Efficiency vs. Power

Here, I’d like to point out that Lotka’s name for his principle is confusing. Power and efficiency are two separate things. The example I use for this when teaching Permaculture is to compare a Hummer and a Honda Civic. The Hummer is about creating massive horsepower from gasoline, while the Civic’s goal is to maximize miles traveled from the same energy input. Even the Civic needs to create a burst of power at startup to kick the engine over, before moving into a state of more efficient long term energy conversion. So Power and efficiency represent system states that may change over time.

We see this contrast at different times of year, for example, in natural ecosystems. Spring is about Power, Summer and Winter are about Efficiency.

Carrying Capacity, Overshoot and Collapse

Ecology has developed the idea of a carrying capacity of some system, usually a geographically defined region. Carrying capacity is often defined in terms of the population of some species, often a top predator, that can live sustainably in the defined area based on the needed energy inputs and stores (such as food availability) provided by the system.

Each system can be defined in terms of a maximum carrying capacity, an equilibrium in which primary production equals maintenance (respiration) as measured energetically. Populations tend toward this maximum, which usually exceeds the optimum carrying capacity, or sustainable carrying capacity. Growth tends to accelerate past the inflection point in the S-shaped growth curve which demarcates the long term sustainable capacity.

A species is in overshoot when it’s population exceeds maximum carrying capacity (Odum and Barrett). Collapse, die-off and extinction often occur when a species is in an overshoot condition (Diamond). The related concept of ecological footprint defines the geographical area required to support an individual, group or population. We are currently experiencing the sixth great extinction event in the life of the planet, which can largely be attributed to human alteration of habitat, climate, atmosphere and chemistry of Earth

Yield

Yield is a system concept that is fundamental to Permaculture (Mollison, Holmgren). The yield of a system is the sum total of all energy stored and converted by a system beyond that needed for the ongoing maintenance of the system itself. Systems operating at maximum carrying capacity produce no yield.

The classic example of yield is the egg produced by a laying hen. In order for the hen system to produce a positive yield or surplus, all its needs must first be met, so we need to expand the system boundary to include those system components that provide the needs for the chicken and all the other components within the system, including safe capture and conversion of all component outputs. Some of these we call “waste” but all waste streams represent potential system yields or resources.

Sustainable yields can be harvested (Holmgren) to become a sustainable resource. This resource can then be used internally to grow the system (power) or reinvested to capture more energy (efficiency) or used to feed another system. Simply feeding an output stream back into the system in an appropriate way can often transform wastes into resources.

Permaculture proceeds by creating small systems groupings called guilds in patterns, in order to create the smallest geographical footprint needed to support all the needs of the systems’ participants, specifically people. The idea is to reduce the ecological footprint of homo sapiens to its minimum, in order to allow natural systems to recover.

Natural capital and services

All natural systems are effectively open systems driven by wild energies provided ultimately by sun, moon, stars and earth. These energies are familiar to us as solar radiation (light, heat, ultraviolet, infrared), winds, gravitational effects, thermal effects (convection, thermosiphon), pressure differentials (chimneys), weather systems, flow patterns, tides, geothermal energy and so on.

Since natural systems, following Lotka’s principle, capture, transform, accumulate and process vast amounts of freely available energy income, they represent stores of natural capital and provide free natural services, as long as they are in a condition of positive yield.

Biophysical and Ecological Economics

Many efforts are currently under way to tie or correlate what we know about energetic and information systems with human monetary and economic systems (Daly, Costanza, Hall, Cleveland, Kauffman, Odum).

Economically, we have treated natural capital (forests, fossil fuels, fossil water, etc.) incorrectly as income rather than assets. This is an accounting error (Daly) of monstrous proportions. Additionally, natural services, such as waste treatment, air cleansing, soil creation, and so on, are not accounted for in our overall natural balance sheet.

The micro-economic equation Profit = Revenue – Expense does not fully include externalized costs of upstream inputs or downstream outputs provided for by free natural services that operate based on natural capital. To the extent that natural capital is consumed or degraded, such services are reduced and need to be substituted in some other, usually less efficient or powerful way (Lotka again).

From this perspective, the trade principles of absolute, and comparative advantage (Ricardo) need to be reconsidered. Since prices have never reflected the environmental or social costs of extraction activities (oil, gas, coal, minerals, agriculture since 1948, forestry, fishing, etc.), these would appear to be exploitive rather than mutually beneficial, to the extent that the local systems are disordered, degraded or do not have their needs met. The concept of system yield provides a theoretical basis for re-localization of basic needs, with export of sustainable yields only for trade purposes.

Resource Categories

Permaculture categorizes resources based on effects of their use. A resource can:

1. increase or improve with use
2. decrease or degrade if not used
3. be (largely) unaffected by use
4. decrease or degrade with use
5. pollute or degrade other systems with use

Some examples are listed below for each numbered item:

1. knowledge, skills, muscles, languages, trails and pathways, viral media, fired neural network paths, sometimes controlled burning of forest, circulation of money, standards
2. rotting vegetables, vacant buildings, evaporating water, melting ice, useless consumption of all kinds, unfired neural network paths, political apathy and cynicism
3. water in small scale hydropower, wind, rock used as thermal store, some insulation materials
4. eroded soils, soil nutrients lost through tillage, fossil fuel use, groundwater and aquifer drawdown, salting desert soils through irrigation, mining operations generally
5. burning fossil fuels, fertilizer runoff, untreated or unused sewage and manures,  industrial use of water for cooling, clear cutting forest, drug use generally, overuse of antibiotics, mixing waste streams which ought to be treated separately (such as mixing drinking water, gray water, urine, feces, storm water and road runoff  before treatment)

Obviously, sustainable systems seek to maximize 1-3 and minimize 4 and 5, however these rules need to be combined with an assessment of whether the resource is initially produced sustainably as yield, and whether the use of the resource produces additional resources with better characteristics.

In general, the worst case is the consumption of natural capital resources which degrades or pollutes other resources without generating substantially higher quality resources. Cutting forest for paper pulp used in toilet paper, and lawn care in general fall into this category.

However, it’s also feasible to use resources in category 4 or 5 if the outcome will produce, heal or replace an equal or greater amount of resources at equal or higher quality over the course of the system’s lifetime than those used. The power to move earth with hydraulic equipment like a back hoe to quickly create rain catchment or plant forest is an example of such a resource use.

System Boundary Issue

Hovering over all these discussions is the question of how to accurately measure, rate and compare system performance, and indeed how small or large to define the scope of the system for measurement. There are many natural and artificial levels that always suggest themselves: nations, states, regions, watersheds, continents, towns, property lines, buildings, etc. An accurate energy accounting of a system needs to define the system scope in order to measure energy flow into, transformation and storage of energy within and energy flow out of the system.

The Permaculture approach is to work from the smallest possible systems upward. Only when a small system is in order and yielding a surplus, should we expand the scope to include a larger system. We look always for solutions within the system itself first.

This is contrary to most economic and political systems which are constantly increasing the system boundary in order to solve problems that are the result of failing to close the loop at a smaller scale. Thus, we have continually attempted to export our problems to a larger and larger arena. The village funds its sewers with money from the county, which gets it from the state, which gets it from Washington.

With the closing of the frontiers, climate change, peak oil and globalization, we have reached a very effective limit beyond which we can no longer export problems. Our externalizing is now radically altering the entire chemical makeup and biophysical characteristics of the atmosphere, soils and oceans of the planet. We must start working within much smaller system boundaries.

Conclusion and Follow Up Questions

This brief sketch has enumerated some fundamental ideas that inform our discussion of sustainability. The design of ground-up sustainable systems that produce sustainable yields must become the basis for our economic and trade practice, according to Permaculture ethics and principles.

Some questions for consideration:

1. Does comparative advantage still operate given theoretically sustainable local systems producing sustainable yield, and does re-localization offer economic advantages over the current system where very few systems could be called sustainable?
2. What drives growth of ecological systems toward maximum capacity? Could there be a type of Jevon’s Paradox operating in the ecology where, as capacity increases it gets used, whether it is optimal or not?

Bibliography

Bateson, Gregory Steps to an Ecology of Mind, Chicago and London: University of Chicago Press, 1972.

Diamond, Jared Collapse: How Societies Choose to Fail or Succeed, London: Penguin Books, 2005.

Hall, Charles, Cutler Cleveland and Robert Kaufmann Energy and Resource Quality: The Ecology of the Economic Process, New York: Wiley-Interscience, 1986.

Holmgren, David Permaculture: Principles and Pathways Beyond Sustainability,  Hepburn, Australia: Holmgren Design Services,  2002.

Korten, David The Great Turning, San Francisco: Berrett-Koehler Publishers, 2006.

Macy, Joanna and Molly Young Brown Coming Back to Life, Gabriola Island, BC, Canada: New Society Publishers, 1998.

Mollison, Bill Permaculture: A Designers’ Manual, Tyalgum, Australia: Tagari Publications, 1988.

Odum, Eugene and Gary Barrett Fundamentals of Ecology, Belmont, California: Thompson Brooks/Cole, 2005.

Odum, Howard and Elisabeth Odum Energy Basis for Man and Nature, New York: McGraw-Hill, 1976.

Schor, Juliet and Betsy Taylor, editors Sustainable Planet: Solutions for the Twenty-first Century, Boston: Beacon Press, 2002.

This entry was posted on Saturday, January 23rd, 2010 at 9:38 pm and is filed under Sustainability, Economics, Permaculture, Energy, Peak Oil, Food System, Global warming. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.