Easter Island and Entropy

Lecture I:  Easter Island and Entropy

Easter Island

1. Easter Island is a volcanic landmass of about 65 sq. miles located 2200 miles west of Chile.  The nearest inhabited island is Pitcairn, another 1200 miles west.  Easter Island is so-called because it was “discovered” by Dutch explorers on Easter day of 1722.
2. The island was settled by Polynesian explorers around 400 AD.  Its early culture was based on extended families, or clans, which cooperated in developing one of the most complex societies in the Polynesian world.  The society originated a written symbol system (Rongorongo) that has never been deciphered.  Rocks and caves on the island are rich in petroglyphs and paintings.  There are stone platform-like public structures oriented toward the summer and the winter solstices.  And of course there are the great stone statues (moai), 6-30 feet high, for which Easter Island is known, of which almost 900 still exist in various degrees of ruin.
3. These statues apparently had a ceremonial use associated with religious cults around which the society was organized.  Clan chieftains were considered divine, and statues erected in their honor remained standing when they died.  The statues perhaps had other ceremonial uses as well, related to various cults located in different parts of island.  It is easy to imagine them as part of “competitions” for the most lavish religious display, like a rivalry for the most lavish cathedral in France or Italy.
4. Archaeologists are unclear about how the statues were moved from the quarry.  One theory is that they were mounted on wooden platforms pulled on log rollers.  Another is that they were anchored on sledges rocked back and forth by levers.  Whatever method was used, it relied on lots of logs and rope.  Rope, along with clothing, was probably made from paper mulberry trees, common throughout the South Pacific.
5. Trees were put to many other uses as well, such as cooking, building wood dwellings, and making canoes for fishing.  Since its soil at first was fertile, the island’s initially ample forests could easily replenish themselves.  But as the population increased, forest depletion set in and eventually became irreversible.  Even when the wood supply was nearly exhausted, production of the moai statues continued, as shown by partially completed works left in the quarry.
6. With depletion of the forests, the rest of ecosystem also began to fall apart.  Soil eroded, leading to food shortages.  These shortages were exacerbated by lack of wooden boats suitable for fishing.  Fighting broke out among the clans for increasingly scarce resources, which depleted remaining resources still further.  Toward the end of the civilization, people were living in squalor and even resorted to cannibalism.
7. During its peak, population of the island was around 7000 (about 110 per sq. mile).  When the Dutch arrived in 1722, it was down to about 3000.  By the end of the 19th century, after several waves of slave traders, only a few hundred natives remained.  The inhabitants still there today are citizens of Chile, living on a bare island used mostly for sheep farming and tourism.
8. For roughly 1000 years after its initial settlement, society on the island continued to grow in both size and complexity.  With this social growth, however, came increasing demands on the supporting ecosystem.  And when the ecosystem crumbled, the society collapsed with it.  The society in effect was the cause of its own demise by growing beyond its ecological limits.
9. This society inhabited a small island in a very large ocean.  We inhabit a small planet in a very large galaxy.  At its peak, human presence on Easter Island averaged out at about 110 people per sq. mile.  By Sept. 2007, population of the planet had reached more than 6.6 billion.  At 58 million square miles of land mass around the globe, that tallies out at about 110 humans for every square mile.  While this coincidence of population densities may be insignificant in itself, there are obvious parallels between the two situations that should be taken seriously.  Could what happened to society on Easter Island happen to human society on Earth at large?
10. As a first step toward a responsible answer to this question, let us look briefly at a famous essay by Kenneth Boulding.

Spaceship Earth

1. Boulding’s essay, “The Economics of the coming Spaceship Earth,” (1966) provides an overview of contemporary industrial economies and of their fixation on continual growth.  In economic thought then current, he points out, both production and consumption are considered to be good things.  Economic success is measured in terms of GNP, which boils down to the amount of natural resources the economy converts into consumer goods.  To remain healthy, an economy must increase production on a regular basis.  This amounts to using up ever-increasing amounts of natural resources.
2. In a memorable image, Boulding refers to an economy dedicated to growth as a “cowboy economy.”  This label symbolizes a mode of economic activity that is reckless, exploitative, and sometimes violent (his words).  Such activity is encouraged by an analogy of nature as an open plain with unlimited room for expansion.
3. The contrasting image is that of earth as a spaceship with limited natural resources and limited capacity to assimilate wastes.  The spaceship economy has a different view of production and consumption.  In its view, the more resources used in producing consumer goods today, the fewer are available for future use.  Emphasis in the spaceship economy is on conservation rather than open-ended consumption.
4. A successful spaceship economy is thought of as one able to meet needs of people on sustainable basis.  In economic terms, a spaceship economy focuses on maintaining capital stock rather than using it up at ever-increasing rates.  Capital stock includes both natural resources like fuel and minerals and “sinks” (forests, lakes) for absorbing wastes.
5. A healthy spaceship economy minimizes total throughput.  Throughput is the quantity of natural resources going into production that end up as pollution or eventually as discarded consumer wastes.  Boulding uses terminology from thermodynamics in describing throughput.  Pollution and wastes resulting from production constitute entropy, whereas resources that go into production constitute anti-entropy or negentropy.
6. Viewing Earth as a spaceship entails recognizing that we have limited negentropy to use in economic activity.  And it also entails recognizing that Earth is limited in capacity to absorb the resulting entropy.
7. Contemporary mainstream economics still operate on the cowboy model.  This is a primary source of our environmental crisis.  To spell out why, we need to gain a basic familiarity with the concept of entropy.

Entropy

1. Entropy is energy expended in doing work.  (This is not a formal definition, but only a partial characterization.)  Work is the bringing about of nonrandom change.  Nonrandom change involves structure of some sort.  So entropy also involves structure.  More will be said on entropy as degraded structure in the next lecture.
2. Forms of energy can be ranked according to work capacity in the comparative terms: (a) highest, (b) midrange, and (c) lowest:
   1. nuclear (in the sun), gravitational, orbital,
   2. solar (highly directional radiation), electrical, chemical, kinetic,
   3. low-grade heat (nondirectional radiation), eventually leaving the earth as black-body radiation.
   Further rankings can be made within (a) and (b).  For example, gravitational is higher than orbital and solar is higher than electrical.
3. In doing work, energy goes from one form to another.  For example, in photosynthesis, solar goes to chemical.  In general, higher forms of energy convert to lower, but not vice versa.  Some forms, however, convert in both directions (e.g., electrical and kinetic, with fans and generators, respectively).  Interconvertible forms are always on the same rank.
4. Doing work involves loss of work capacity. It degrades energy involved.  For example, solar energy is degraded in the process of photosynthesis.  Moreover, work conversions are never 100% efficient.  For example, work capacity is typically lost when higher forms of energy go directly to low-grade heat.
5. Generally speaking, energy degradation does not entail complete loss of work capacity (save in going directly to low-grade heat).  For example, chemical energy resulting from photosynthesis still has work capacity.  It just has less work capacity than the solar energy expended in producing it.

Laws of Thermodynamics

1. First Law: the amount of energy (of all gradations) in a closed system is constant.  The universe (the “totality of everything”) by definition is closed. The First Law is quantitative, in that it deals with quantities of energy.
2. Second Law: entropy in a closed system increases with time.  As time progresses, work capacity decreases.  Even as work capacity decreases, however, total energy in the system remains constant (the First Law).  The Second Law thus is qualitative, having to do with loss of work capacity.
3. An open system allows energy to enter and entropy to exit.  But as in a closed system, all work in an open system degrades energy and produces entropy.  Entropy remains in existence somewhere even when it exits an open system.
4. Energy conversion diagrams:
   

    

   

   
   Figure 1.1:  Energy rankings (1), from Kenneth Sayre, Unearthed: The Economic Roots of our Environmental Crisis. Used with permission.

   

   Figure 1.2:  Energy rankings (2), from Kenneth Sayre, Unearthed: The Economic Roots of our Environmental Crisis. Used with permission.

   

   Figure 1.3:  Energy rankings (3), from Kenneth Sayre, Unearthed: The Economic Roots of our Environmental Crisis. Used with permission.

   1. The columns represent different grades of energy, higher ranking forms to the left, lower to the right.  No specific forms are represented; only relative gradations.
   2. Differing work capacities are represented by the multipliers ((x4), (x3), etc.), as well as by different shadings.  Each column starts with 10 segments.  But these segments represent different work capacities in different columns, increasingly less from left to right.  The left-most column shows 40 units of work capacity, then 30, and so forth.  Number of segments and work capacity assigned to segments are completely arbitrary, chosen only for purposes of illustration.
   3. Time sequence is represented by order of the diagrams, 1.1, 1.2, 1.3.
5. The three diagrams shown pertain to a closed system, indicated by the same number of energy units (100)  being present through time.  As time progresses, only qualitative changes occur, in that there is progressively more entropy and less energy available for work.
6. Additional rules change a set of representations like these into an open system;  namely, (i) a column can increase in usable energy without decrease in a column to left (in which case energy is imported), (ii) a column can decrease in usable energy without an increase in any column to the right (in which case energy is exported).  Thus an open system can gain capacity for work and can get rid of entropy.  Further details on the operation of open systems can be found in Ch. 1 of the course text Unearthed.
7. Our concern in this course is primarily with biological systems, which import high-grade energy from their immediate environment and discharge entropy resulting from metabolic activity.  The operation of biological systems is taken up in the next lecture.