“In a future that is as unavoidable as it will be unwelcome, survival and sanity may depend upon our ability to cherish rather than to disparage the concept of human dignity. My purpose in writing this book has been to enhance that ability by providing a clear understanding of the ecological context of human life.”
Overshoot, William Catton
I fear our ignorance more than our evil. In my experience evil is self-defeating, ignorance on the other hand, seems to know no bounds.
Contemplation is the art of penetrating thought that reworks previous understanding, mulling over something until insight comes forth from its gestation period. In Eastern traditions there is a set of practices designed to train the attention and increase the length of time the contemplative state can be retained. In these traditions value is placed on the depth of an insight, on how deeply it can be “felt.” The meditative position we see in statues of the Buddha with legs crossed and body upright allows stillness to develop and it has been found a still mind follows a still body, eventually. This meditative position is also one of the most grounded a human being can take, meaning in it can you can weather shocks, you can let energy pass through your emotional body into the earth on which you sit. If an insight arises that is so new and penetrating that it rocks your world, as we say, you can just breathe through it, watch it arise and eventually dissolve. Insight after insight, ignorance is diminished.
Without developing wisdom, diminishing ignorance, we go round and round in circles. Doing the same thing over and over again even though it doesn’t work is part of our craziness. Why? It has been suggested that more often than not decisions are made in ignorance of the relevant context in which they are being made. Consideration of the whole environment in which events occur is studied in what is known as systems theory. It is the study of complex systems; how they behave, what makes them tick and how they react to changes. Basically, the way towards not just knowledge but wisdom lies along the route of increasingly incorporating the environments of events in one’s contemplations. With the introduction of the environment we have entered the field of ecology.
We are only able to think along pathways we have terms for; concepts must exist for at least the structural aspect of the act of thinking. Every subject of study has its own vocabulary, using labels to communicate the context of its understanding. In today’s post we are building up to an understanding of the key ecological concept of an environment’s carrying capacity. We will work our way towards this through a series of steps each illustrated by images worthy of our contemplation. Mass, energy and light are the fundamental steps that will lead us to this week’s larger view.
An ecosystem is a name for an organized unit, a logical level that is complete in that it includes all the components it needs to survive over the long term. Ecosystem models are created when a boundary is drawn around the functions of interest; a patch of garden, pond, forest or planet. As soon as boundaries are introduced a system is defined. Ecosystems are open systems which mean these models explicitly include interactions with their environment. There will be inputs, typically energy and outputs including waste heat and processed materials.
Since ecosystems model the earth’s biosphere it helps to have a clear internal reference of our planet’s position, to include the earth’s temporal and spatial environments when bringing it before the mind’s eye. In the early solar system orbiting dust grains collided and stuck together in a process of accretion that in approximately 10,000 years produced boulders and asteroids a kilometer wide. Over the next million years these objects continued to collide forming moon and mars sized objects. These baby planets crash into one another over tens of millions of years until there were just a few survivors, each in its own orbit. So far this is all standard stuff from a high school astronomy class but to begin to pierce the mist of time and absorb your ancestry in your bones it might help to contemplate two details of the process, seeing them as they might have unfolded; the formation of our moon and the arrival of water.
When the rocky inner planets form, the denser elements sink into their planetary cores. These iron and nickel cores support the less dense molten magma consisting of rocks rich in oxygen, silicon and such. Above the magma the planetary crust forms. Some 50 million years after the accretion began early earth collides with another baby planet with such titanic force that it melts the crust and sends vaporized rock orbiting our young planet. In this final major accretion event our moon was born. The vaporized rock collides and sticks until our companion is formed, roughly 25% as big as earth but huge on the horizon with an orbit only 10,000 miles away. The moon has been receding from the earth ever since. The moon, uniquely in our solar system, lacks an iron core since by the time its birth collision occurred these heavier elements had already sunk to the earth’s core. Only the magma rocks were ejected.
As the great gas giants of the outer solar system complete their formation they perturb the orbits of the meteors and asteroids. On earth the bombardment becomes extreme yet it also brings water, the essential element for life. Only objects far enough from the sun are able to contain water that is not boiled off, far enough away to form ice. Out between Mars and Jupiter today we can see one of these asteroids, 1-Ceres. At close to 1,000 kilometers across it is nearly round, a proper planetoid, but not very dense probably because it contains a large amount of water ice. The earth’s waters, covering 70% of the planet, could all have arrived here in collisions with just a few such asteroids. During contemplation picture in your mind’s eye the arrival of these bubbles of life giving water on our fiery, volcanic planet until a natural awe and gratitude arise. It is difficult to pierce the mist of time but we have a knowing, a type of intuition about what we are, as it were, built through a long chain of cause and effect. Our ancestors were titans.
The most famous photo of all time was taken December 7th, 1972 by the last manned mission to the moon, Apollo 17. This picture of the earth as seen from the moon is profound on so many levels. Of interest right now is how absolutely self-contained our planet is materially. The mass of our planet was gathered ~4.5 billion years ago and aside from a few meteors here and there has not substantially changed its material content since. All life ever has had or will ever have to survive and thrive is here on the planet right now. Materials cycle. They are used over and over again without losing their ability to function. All materials have their circular paths like water as it moves from ocean to cloud to rain to river to ocean to cloud…
Materials cycle, energy does not. Energy is a one way flow which can be temporarily captured, diverted, used to build complexity and sustain life as anti-thermal dynamics yet inevitably, in total, will always drive towards an increase in entropy, towards a more dispersed, useless state. Energy cannot be reused. It can be transformed from one form to another, as we see in photosynthesis magically converting light into food, but every transformation will only proceed if there is a degradation from concentrated energy to more dispersed and dissipated.
Earth, our jewel in space, is continually bathed in the light of our sun, bathed by radiation about 10 percent ultraviolet, 45 percent visible and 45 percent infrared. This unceasing flow of energy provides the one way gradient on which the web of life weaves its majestic forms.
All the ecosystems on our planet depend on the energy received from the sun (aside from a few specialized ecosystems that use the energy of geothermal vents). These ecosystems structurally consist of the primary producers and the secondary consumers, the plants and the animals. The primary layer is able to fix sunlight for the manufacturing of food from inorganic materials; green plants, algae and water plants. This biotic component is called autotrophic, which means self-nourishing. The secondary layer is heterotrophic meaning other nourishing. Since heterotrophs are unable to create their own food they must acquire it by consuming the complex materials created by the autotrophs.
The secondary, consumer layer is usefully further divided into herbivores, carnivores, omnivores and saprovores. The herbivores eat only plants, carnivores feed on other animals, omnivores feed on both plants and animals and saprovores feed on decaying organic materials, detritus. Most people have encountered these terms before except perhaps the term saprovores, which is a touch ironic. Saprovores feed on decaying organic materials. Petroleum is decaying organic material. When humanity started its dependency on non-renewable fossil fuel energy sources it entered into a detritus ecosystem. These ecosystems are characterized by exuberant growth followed by a die-off crash. More about this as these posts proceed.
Today it is worth pausing with the saprovores a moment to emphasize the role of the compost heap in the larger scheme of things. When the complex biotic materials break down they do not “die” in any ultimate sense. There is no place cut off from the rest of the whole of Gaia in which the damned are cast off. There is only the compost heap, the recycling of every element in making way for new life to flourish and in its turn decay. Christian mythology has at times been understood to teach that there is a second death, one of the soul in hell above and beyond the death of the body. There is no such second death, the sun at midnight is ever the sun, and the dark humus of the compost heap is the farthest reaches of the truly existing.
The recognition of autotrophs and heterotrophs provides more than just a classification scheme. By following energy relationships through food webs it also uncovers the fundamental structure of earth’s ecosystems.
The primary trophic layer of green plants supports the herbivore layer which is known as the primary consumers. The carnivores that eat the primary consumers are known as the secondary consumers and finally in some ecosystems there are tertiary consumers dining on the secondary consumers. Each layer is able to utilize only about 10% of the energy transferred to it; about 10% of the energy is converted into biomass. This creates what is known as the energy pyramid with a large base of primary producers supporting increasingly smaller layers above it. For example in a simplified model a patch of field with 1,000 grams of wheat could support 100 mice as primary consumers. In the field 10 foxes could survive as secondary consumers on that many mice and those foxes could support 1 eagle as a tertiary consumer. All terrestrial and aquatic ecosystems are structured in this energy pyramid form.
Another way to track energy through an ecosystem is to look at the respiration rate in relation to the total production of biomass. Any complex structure above absolute zero temperature requires, as Schrodinger has shown, a continual pumping out of the disorder to maintain its order. In ecosystems the complex biomass structure is maintained by the total community respiration which, we could say, pumps out the disorder. The ratio of total community respiration to total community biomass (R/B) is the maintenance to structure ratio, the thermodynamic ordering function. Nature might seek to maximize this ratio, a subject we will return to when our discussion takes up the dynamics of ecological succession.
We see there are finite quantities of material and a fixed flux of radiant energy on earth. Our planet is defined by these limitations. The thermodynamic energy laws give earth its characteristic dynamics, strictly delimiting what is and what is not possible. With these tools on our cognitive tool belt we are now in a position to begin to appreciate the concept of an environment’s carrying capacity.
The carrying capacity is the maximum population size of a species that the environment can sustain indefinitely. In population biology it is defined as the environment’s maximal load. Next week’s post will look at carrying capacity in more detail but I leave you with two ideas to ponder until then. For an environment to sustain a population indefinitely its material and energy needs must come from renewable sources and there cannot be significant damage to the organisms or their environment; negative impacts lower the carrying capacity. The second idea is that the carrying capacity of an environment can change over time due to changing conditions. Some of the many variables that directly affect an environment’s carrying capacity include; changes in the availability of food and water, or changes in the ability of the environment to process wastes, or changes in the availability of energy in a useable form. In today’s world all of these variables are changing in ways that are shrinking our planet’s carrying capacity. This is the larger, slower reality behind the ephemeral headlines.