Monday, March 15, 2010

Ecosystem Modeling

We're in Day Three of the permaculture course in Belize and today our assignment was ecological systems. This lesson also seems relevant to The Great Change so lets recap.

One favored source from which to purloin instructional material is the Centre for Alternate Technology’s MSc program in Advanced Environmental and Energy Studies in London and Machynlleth, Wales. CAT has developed a series of modules that should, in the society to come, replace a very high percentage of the courseware now being peddled in most tertiary schools. We are particularly fond of Damien Randle’s lecture on world resources, which comes towards the end of the first AEES module.

An ecosystem is no more nor less than the sum of individual responses of diverse cooperating or competing organisms to stimuli from events in their environment. Diversity is a sign that there is a high number of stimuli and that the system has become dynamic in response. A great many small parts, making separate and nimble adjustments, solve problems better than a few large parts responding ponderously.

Randle, referencing Limits to Growth, Vital Signs and State of the World studies, describes four possible scenarios for coming to grips with carrying capacity. The first is no discontinuity — the resource or resources are able to expand and grow, so use can grow; population and carrying capacity expand together. An example of this might be late 19th century transportation that was becoming constrained by horse manure and coal smoke in cities and barge canal, sail or rail capacities across greater distances. Gasoline and diesel fuels rendered those old limits obsolete (for the time being).

The second is a sigmoid response. There is a good signal that the resource is constant (seasonal daily sunlight, for instance) and a responsive organizational or systemic structure aware of that limit and diligently proactive. The population demand or economic growth self-limits as it approaches the ceiling. An example in gardening would be the size of one’s yard. One can still squeeze additional yield by layering in understory and going vertical with trellises and “living walls,” but the prospect of spilling over into a neighbor’s yard imposes an unmistakable psychological boundary.

The third type is an oscillating overshoot, where the signals are delayed, time-lapsed or masked but the systemic erosion caused by temporary overshoot is not permanently damaging. As the signals vascillate between positive and negative, there is uncertainty, and shifting response — on again, off again. The organizational structures are not nimble enough to quickly recognize the pattern and anticipate the volatility, but respond well enough to allow the resource to recover without suffering permanent damage. An insecure and disruptive economic oscillation, rather than a steady-state, is sustained.

The fourth type is more serious. The signals are not recognized. Perhaps they are too obscure or too rapid for the sophistication of the dependent organization. No adjustments are made as carrying capacity is reached and exceeded until it is too late to avert lasting damage to the resource. There is a permanent erosion in the resource’s capacity to support production even after the system recognizes its condition of overshoot and adjusts demand downward. This is what has happened to many fisheries, forests and agricultural landscapes. It appears inevitable now for a great many non-renewable resources, whether they be oil, coal, uranium, or many of the rarer elements that go into hybrid cars, wind generators and photovoltaic cells.

After reading John Michael Greer’s The Long Descent, we added a fifth type to the CAT scenarios — catabolic collapse. Once more, the signals are not recognized because the reality of the problem challenges the core beliefs of the dependent organization, such as a classical economics that admits of no limit in supply as long as there is demand. Greer postulates that overshoot may not follow a straight linear decline but rather may vacillate between plunges and temporary states of repose, using up “banked” resources that are retasked and recycled. The descent curve resembles a stair-step, arguably the experience of the global economy since peak production of liquid fossil fuels and their substitutes was reached in the 2006 to 2008 period.

As Richard Heinberg recently observed, the catabolic model was explained in the seminal Peak Oil article in Scientific American that petroleum geologists Colin Campbell and Jean Laherrère wrote in 1998. Heinberg recapitulates that prediction:
Sometime around the year 2010, they theorized, stagnant or falling oil supplies would lead to soaring and more volatile petroleum prices, which would precipitate a global economic crash. This rapid economic contraction would in turn lead to sharply curtailed energy demand, so oil prices would then fall; but as soon as the economy regained strength, demand for oil would recover, prices would again soar, and the economy would relapse. This cycle would continue, with each recovery phase being shorter and weaker, and each crash deeper and harder, until the economy was in ruins. Meanwhile, volatile oil prices would frustrate investments in energy alternatives: one year, oil would be so expensive that almost any other energy source would look cheap by comparison; the next year, the price of oil would have fallen so far that energy users would be flocking back to it, with investments in other energy sources looking foolish. Investment capital would be in short supply in any case because the banks would be insolvent due to the crash, and governments would be broke due to declining tax revenues. Meanwhile, international competition for dwindling oil supplies might lead to wars between petroleum importing nations, between importers and exporters, and between rival factions within exporting nations.

Looking at ecosystems, we can say that they respond to stress by shifting quickly and altering their biological makeup. Most changes in the natural world occur as sudden bumps rather  than gradual evolutions: earthquakes raising the Andes; oceans claiming coastlines in the wake of hurricanes; wildfires shifting forest to plain. An ecosystem is the result of the sum of individual responses to catastrophe, or any stimuli that forces a change upon the status quo. Biological diversity, indicative of a high level of stimuli, provides insurance for the system. Global extinction of an entire species is very rare (or was before the Anthrocene), but local extinction and replacements are common. Ecosystems clean house, recruit, re-diversify and recharge.

The antidote for the solastalgia that comes of recognizing the now undeniable human overshoot and collapse trajectory is very simple. Permaculture. Earth care. We can cultivate our human ecosystems the same way forests, coral reefs and mountains restore an optimal balance of habitats and food webs in response strong external stimuli. We can reskill and retask our children, grow diversity around ourselves like a cocoon, line up redundant sources of support for each and every need, and learn to swim within, not against, the prevailing current.

It is good to bear in mind that Gaia will be doing this, too, with or without us. 


Anonymous said...

Can we have a link for video or information about the AEES module you mention?

Peaksurfer said...

Next time Google!




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