A human being may live to see 100 years go by, and yet still a century is an awesome span of time to grasp. Now multiply that by ten, and we have something truly humbling - a thousand years. Even if every event in a millennium had been meticulously documented and you were a historian well-versed in them, your mind simply could not encompass the reality of a thousand years. Multiply that by ten, and you are talking about scales on which dozens of powerful civilizations have risen and fallen. Now telescope that outward by a factor of a hundred, and you have a truly staggering gulf of time. But there is no mystery to time - it is just the unfolding of universal processes, so I can say this with confidence: I will show you a plausible and persuasive million-year future for humanity.
This is perhaps a foolhardy claim, I know. But beneath the transient political and economic currents that appear to drive human civilization is a much simpler, and far more easily understood principle: Energy. If you want to know how life will develop over large timescales, "follow the money" - i.e., follow the energy that guides the large-scale evolution of civilizations, species, and ecosystems. Life pursues the source of its energy while spreading from the margins in pursuit of new sources. The large-scale meaning of this fact will become apparent in the course of this diary series.
Table of Contents
(Current part highlighted)
I. The Energy History of Life
II. The Energy History of Humanity
III. The Next Decade.
IV. The Next Century.
V. The Next Millennium.
VI. 10,000 Years.
VII. 100,000 Years.
VIII. Mark: 1 Million Years.
In Part 1, I will illustrate the basic energy processes that drive both biological and technological evolution, from which I will be deriving my model of humanity's future in subsequent parts.
I. The Energy History of Life
Our story begins with a star. It could have been any star, but this one was stable enough to emit a relatively consistent flux of energy; high enough in mass to have formed a substantial cadre of planets and other objects in its orbit; and yet low enough in mass not to have gobbled them up or smashed them into smithereens against each other. This star was hot enough that a planet could be far enough away not to be tidally locked (i.e., not have one side always facing it) - which is important so that energy is distributed over its surface - while still receiving enough energy to maintain water in a liquid state. It was also cool enough that a planet close enough to hold liquid water wouldn't be constantly sterilized by too heavy a flux of UV or X-rays.
A planet in this particular orbital zone around the star, Earth, thus existed in an energy environment where complex organic molecules could spontaneously form in solution (i.e., in water) out of simpler sub-components and endure for relatively long periods of time before collapsing or being broken down by random collisions or absorption of high-energy rays. Among the multitude of random chemical reactions occurring in this soup, some of them were replicative - a complex molecule would cause a process whereby chemicals in the environment would be transformed into a copy of itself.
The vast majority of such replication runs ended when they reached the limits of local resources - i.e., sufficient and continuous access to both direct energy (sunlight or volcanism) and indirect energy (that stored in other molecules). But because spontaneous occurrences were continuously resulting wherever the right conditions and materials were present, eventually random mutations in the process would occur that allowed for more efficient exploitation of available energy: Molecules could last longer, replicate faster, and obtain more from the same environment than before. This run of molecular replication might also have ended, but new ones were constantly springing up, and eventually one occurred that would not end - that has not ended to this day.
Such a process is possible because the output is variable enough to selectively seek out and exploit resources beyond the immediate vicinity and, over the long term, outside the ability of the current generation to utilize. In other words, this is brute force evolution: Propagate in all directions, and some of the offspring will probably find survivable conditions and flourish. In this way, the spread of living organisms traces out the available energy environment by default: Those who strike out in desolate directions and die will contribute nothing to the overall movement and evolution of the species, while those who flourish map the environment by their very existence.
This blind propagation, in other words, traces out the passable "roads" between rich plains: Natural selection is thus guided by location in the environment, while that based on the intrinsic properties of an organism occurs most strongly under marginal conditions that are neither terminally desolate nor bountiful. Such boundary conditions, where survival is possible but marginal, will yield a high degree of adaptation in the organism and iteratively lead to the evolution of mobility: I.e., the ability to cross uninhabitable wastes rather than being bounded by them.
Instead of having tons of offspring in every direction, the mobile organism maintains its own integrity long enough to move around until it discovers sufficient resources to trigger reproduction. By doing so, it is able to exploit discountinuous resource pools otherwise blocked by poorer conditions, moving from place to place and developing the capacity to escape negative environmental changes. One of the first adaptations toward this end, though not mobility per se, was the spore - a state of rugged dormancy triggered by harsh conditions, and ended by the reappearance of more favorable ones.
A spore doesn't move around by itself, it just sits there until time either improves conditions where it lies, or carries it somewhere more favorable, but the principle is the same: Adaptation allowing for access to resources that are discontinuous either in time or space. It is the ability to cross desolate, otherwise uninhabitable gulfs in order to reach better places and flourish. While a spore is not mobile in itself, it illustrates the power of mobility by its passive exploitation of time: So how much more potent is an adaptation that allows organisms to move themselves, rather than wait to be moved?
This is the origin of the bifurcation between "plant" and "animal" as commonly conceived (though not biologically accurate) - between species that rely on passive triggers and default conditions to survive vs. those capable of relocating. Rather than mangling taxonomy, we can call these two categories "Root" and "Spore," reflecting their respective natures - the sessile and the transient. While this is not an absolute distinction, it is a meaningful and highly useful one in forming my thoughts on the future. However, the most important part of the distinction is where it ends, as I explain below.
Both Root and Spore biota require three things: Energy, materials for the energy to act upon, and water to facilitate the chemical processes undergone by the materials due to the energy. What distinguishes them is the process of locating those resources: Spore species don't need their raw materials to be immediately available in order to grow - they evolved behavioral adaptations to survive and flourish despite environmental discontinuity: Everything from the random swimming of microbes to the conscious seeking of complex mammals.
But here is the upshot: Both Root and Spore flourish where these necessities are most optimally balanced and abundant. In fact, the more balanced and abundant the resources are, the more that Spore biota begin to resemble Root - animal life becoming strongly connected to a single location, highly adapted to a small local niche, and integrated into the ecosystem. While the animal life in tropical rain forests is highly diverse, it plays only a subordinate role: Rather, passive organisms like trees and fungi are overwhelmingly dominant in shaping the environment. The plant life is vast and dense, while animal species are shunted into tiny niches with poor long-term prospects should environmental change occur.
Animals, however, dominate the middle-ground cases - environments where resources are scarce but not chronically unavailable; where water and energy are not everywhere, all the time, but are accessible. In other words, an environment where the Spore function is most beneficial to the overall ecosystem. The plant life depends a lot more on animals in those environments - on insects delivering pollen, animals eating fruit and scattering seeds in their droppings, and so on. The same things occur in tropical rainforests, but they're not nearly as relevant because it doesn't matter where a seed lands: Water is abundant, the soil is rich, and if there's any available sunlight through the canopy, something will grow there.
On the other hand, it doesn't matter where a seed lands in a desert either, and for a remarkably similar reason to that for rain forests: The plants are already where the resources are. In fact, in a desert, animal life can be ecologically negative - the seeds might be carried away from the oasis, and scattered on useless ground. Hence the distinctly unwelcoming character of cacti (to name one example): Better the plant not be eaten and its seeds fall as near as possible to maximize the chance of having water.
The point I would like to illustrate here is that Spore is an evolved means for propagation of Root - i.e., animals are, ecologically, a means of supporting sessile life in boundary conditions. On either side of the boundary - rain forests or deserts - the Spore function is either mooted by abundance, leading the entire ecosystem to resemble Root, or made uneconomical by extreme desolation, in which case it represents the degenerate case of Root. With few exceptions, plants and animals both prefer to stay where the water is rather than going anywhere. In middle cases, however, animals are highly migratory and plants are more seasonal - the latter depend on the comings and goings of the former to give them a wide and healthy distribution.
Where am I going with this? Bear with me: Photosynthesis. The Sun was already the overwhelming source of energy for life on Earth well before photosynthesis evolved - a far more abundant and available source than volcanism or radioactive decay. So when organisms evolved the ability to directly translate solar energy into cellular processes, they were making a giant leap forward. Sunlight isn't just an environmental condition for plants, it's their food. And since plants are the food of animals, and those animals feed still other animals, photosynthesis radically expanded the potential of life on Earth by evolving a more direct path to a massive and inexhaustible energy source.
In fact, if we look at life as an energy system, plants are far more highly evolved than human beings at present. We depend on nth-degree transformations of energy gathered directly by plants, that were then eaten by cows and pigs (i.e., "meat") or dinosaurs (gasoline), or else burn fossilized remains of plants (coal) - an unsustainable, dirty, and inefficient approach to utilizing environmental energy. But here's the thing: Photosynthesis is an evolved life process, which means that it had to develop incrementally from the resources and adaptations already there. In other words, it's the best solar power system a billion years of random organic chemistry can build.
Which is nothing to sneeze at, of course - it's still better than anything human beings have come up with yet, in our all of 40 years of trying, but the fact that photovoltaic (PV) solar power systems are now within sight of becoming competitive with fossil fuels (granted, with subsidies initially) - suggests we haven't even begun to realize its potential.
Life has not even begun to tap the potential of the Sun - the source of the energy that drives our biosphere. What happens to human civilization - indeed, to all life that we increasingly dominate - as our economies and our lives begin to tap into this awesome power, and our development as a species becomes directly guided by solar energy? The answer is "a lot," and I'll be spending this diary elaborating on that. But for a more immediate answer, look back to what I said earlier: In abundance, Root dominates Spore. The exact implications of that for the future of human civilization are explained later, but trust me - they are not at all what you think.
II. The Energy History of Humanity
Several million years ago, a species of primate lived in small numbers in the primordial rain forests of Africa. It obtained its energy mainly by foraging fruits and nuts or eating insects, perhaps with the occasional treat of a bird or smaller mammal killed with a rock. Although there were many other species of primate throughout Africa and Asia, they were each small in number and firmly rooted to localized areas in keeping with the nature of rainforest ecology described above. There was nothing particularly special about it other than a slightly higher degree of behavioral adaptability, the exact nature of which remains a subject of debate.
At some point, and for whatever reason, the environment of this species became somewhat less nurturing - not brutal, but perhaps requiring a moderately greater level of cunning and broader geographical range to survive. It found itself on the margins between ecological abundance and deprivation, becoming iteratively more suited to seek out scarcer resources across wider distances. Under these conditions, our arboreal primate ancestor gave birth to a multitude of hominid species - some of whom remained close to the jungle while others ranged out into the plains and savannas. From the margins of the Root, the Spore was born: A species-level manifestation of a systemwide fractal property.
Animal survival in a middle-case environment depends on mobility, so in evolutionary terms the anatomy of arboreal primates had both advantages and disadvantages for living outside the rain forest: Having four hands is not very useful in a region where the tree canopies are not continuous, and where significant distances have to be covered over open ground to find food and water. However, hands allow a significant short-range advantage over paws or hooves - the ability to throw things and kill other animals at a distance.
As a result of this duality, two distinct evolutionary approaches occurred: One, which led to the Great Apes, had highly muscular forelimbs for knuckle-walking - anatomy well-suited to living on the margins of the rain forest, but not for covering large distances over open ground. The other branch developed powerful hind limbs and feet for erect walking, freeing the forelimbs to become specialized for precise manipulation, and this is the path taken by the hominids. Not surprisingly, it was the hominid line that broke free of the rain forest completely, and gave birth to species that lived in wide-open plains with sparse foliage.
Because of its elegant balances, human walking is an evolutionary marvel of energy efficiency, allowing us to travel long distances at a relatively small caloric price. In other words, as a result of a more energy-efficient anatomical adaptation, hominids not only had a much larger habitable area, but needed fewer calories to survive in it.
Perhaps even more importantly, foot-walking eventually created the ability to jog: A form of locomotion so efficient that it becomes possible to run prey animals down into exhaustion, even if they are much faster. Like all evolved behaviors, this would have been a process of iterative reinforcement with slow anatomical changes resulting from natural selection: An earlier hominid ancestor might have simply had a longer sprinting range than its ape cousins, and that advantage would have been progressively extended into a more optimal process with mid-range speeds - the jog.
Unlike a typical savanna predator, who will give up the chase if its prey gets too far ahead, a hominid capable of jogging could have just kept going for hours - following tracks and making the prey sprint for its life several times in the same day, each time getting less of a lead until it finally failed to escape. It sounds monstrous, and indeed it is: By the time of modern homo sapiens, the ancestral hunter was the Terminator of the African savanna, fixated and relentless - a killing machine capable of hunting other species to extinction. But the long-distance stalking of prey would have selectively increased dynamic memory and versatility, contributing to the evolution of our intelligence.
Given this extended range and versatility, our ancestors were able to expand their access to all three biological necessities: Energy (food calories), raw materials (food components), and water. But the sole source of energy was still consumption of other organisms, and our omnivorous digestive system's ability to deal with significant amounts of raw meat was limited. Earlier hominid hunters may have had to do a great deal of tool-assisted tenderizing and mashing before they could even chew food from a kill, let alone digest it well, so both the size of prey and the caloric benefits would have been initially limited.
That changed at some point, when hominids (the earliest known being Homo erectus) developed the ability to make fire: Omnivore digestion was augmented with an external energy process, making it practical to eat large quantities of meat, more quickly, and while expending fewer calories in the process of preparation. Additional benefits of fire were, of course, that it made living in colder climates possible, further expanding the range of accessible environments, and also providing security against large predators who would be afraid to approach it.
At this point, the hominid line began to fundamentally diverge from other animals: We now had a powerful source of energy beyond our own digestion, overcoming the biological compromises of the omnivore digestive system and allowing true generalization of the human food base. Every non-toxic plant and animal entered our diet to varying degrees, and most of what was inedible could be used as fuel for cooking fires. With the Promethean gift, our ancestors slowly spread across the planet into environments that earlier species had never penetrated: Boreal forests, temperate pine woodlands, steppes, tundra, and so on.
Primordial humanity had leapt into an entirely new energy track by mastering the art of fire: As long as there was fuel available and prey within practical hunting distance, biodiversity was no longer a constraint on expansion - it was no longer necessary to live in a thickly-populated ecosystem where there was always prey and forage over the next hill. Prehistoric people could now survive in echoing emptiness, ranging far and wide to hunt migratory herds, and living practically alone amid the grasses and silent Northern forests.
Hominids (including H. sapiens) lived in this condition for hundreds of thousands of years, hunting and gathering over whatever ranges the environment required. But about 75,000 years ago, a particularly potent strain of H. sapiens migrated out of Africa after a supervolcano in Indonesia temporarily altered the climate and reduced the H. sapien population down to a few thousand individuals. This strain's advantages over its contemporaries remain unclear, but we can surmise that the catastrophe had selected for enhancement of the same qualities that had originally made the hominid line so successful: Versatility and mobility.
What is known about these people is that about 50,000 years after their emergence from Africa, they began to develop culture: Jewelry, sculpted figures, and art, among other things. Why other hominids never did this (as far as we know), and why it took human beings 50,000 years to begin doing it, is unknown. The most likely explanation is that a neurological adaptation occurred, creating the physical basis for the behavioral adaptations we define as humanity. Despite tool use, instrumental intelligence, and probably very familiar social patterns, homo sapiens before this point may not have been psychologically capable of symbolic thinking or complex communication.
Still, even with fully modern psychological capabilities, not much changed in the ensuing 10,000-15,000 years: Humans remained exclusively hunter-gatherers, migrating with the herds and leaving behind very little of themselves apart from trinkets and cave paintings. From an energy perspective, nothing had changed at all since the advent of fire-making hundreds of thousands of years earlier. But at some point both hunters and gatherers began to recognize patterns in nature that governed the ebb and flow of their food supply: They saw correlations between the motions of celestial objects and the abundance of forage, which they naturally would also have noticed being associated with the migrations of herd animals who fed off the land.
Over millennia of quiet, unthinking repetition of foraging behavior, certain knowledge began to accumulate: First, that there are cycles in nature directly relevant to human survival - a fact that is not at all obvious to someone who never thinks beyond their next meal. The recognition of this fact was how human beings first conceived of time scales longer than a single day, and began to use lunar cycles to prepare for migrations rather than just haphazardly following herds. Second, that plants come from seeds - a difficult concept for an illiterate forager to independently deduce: Seeds look nothing like the plants they become, are much smaller than those plants, and nothing you can do to a seed in a single day will force it to grow into a plant.
Thirdly, people realized that the abundance of forage in one season corresponds to the amount of rainfall in prior seasons - something also not obvious on any short time scale: Dumping water on the ground does not cause edible plants to spontaneously appear. Fourth, that herds move with the ebb and flow of the plants they eat - a realization that required understanding other animals to have causal motivations rather than moving according to mysterious and inexplicable forces.
In fact, all four of these understandings had to develop together, because they interlock and require long-term thinking: (1) That the abundance of food goes through cycles much longer than a single day; (2) that plants grow from seeds; (3) that plants need water to grow; and (4) that both the migration and size of prey herds depends on the growth cycles and abundance of the plants they eat. Now, these were not understood in the intellectual, systemic way that we understand them - prehistoric peoples had to accumulate the understanding intuitively, without the benefit of complex reasoning or information-rich language. This is why it took thousands of years to figure out, and why even then it took so long for people to make use of the understanding.
But once they did understand it, the knowledge began to change how people went about hunting and gathering: It became less haphazard and developed into a set of traditions that would increase the food supply over the long-term - for instance, deliberately scattering seeds in certain parts of the ground at certain times of year as marked by lunar phases. Or if there was an abundance of forage, people might deliberately feed part of their gathered food to other animals in order to attract them and build up their size before killing them.
To give up presently available food, such as edible seeds, for the promise of more food later was a radical advance. Slowly, over countless generations, these traditions built up a critical mass of useful practices until they became what we recognize as agriculture and animal domestication: Hunting and gathering converged into a single enterprise. Land would be cultivated both for human consumption and the organized raising of food animals, although in most places the environment was still too poor for these practices to fully support the population - they were only an augmentation to hunting and foraging.
However, there were a few special areas of the world - in particular, warm-climate river deltas such as Sumer, the Lower Nile, and the Indus delta - where the soil was rich due to sediment deposits from the river, water was abundant, and significantly-sized flocks of domesticated animals could be supported. Despite their local abundance, these deltas were different from tropical rain forests because they were geographically isolated, often surrounded by land that was virtually useless, and thus people who settled there were also relatively isolated. As a result, the rewards of expanding the local food supply exceeded what could be gained by migrating. It was in these areas that agriculture and pastoralism evolved most rapidly, and where humanity first experienced the condition of routine surplus.
What was occurring in these settlements was that human beings were learning to control and expand their main source of energy - food. As a result of this control and the ensuing surpluses, the human population expanded beyond what the uncultivated environment could have supported or what a delicately-balanced rain forest could have tolerated. From one stable Root condition - primordial rain forest ancestors, living in small numbers in local niches - our line had moved through hundreds of thousands of years of Spore migration to the next stable Root condition: Agricultural settlements. What had changed was that we had moved upstream in the energy chain, and were no longer passively absorbing the bounty of an existing ecology - humans were now building their own ecologies out of latent environmental potential.
Even with the advent of agriculture, however, most human cultures remained hunter-gatherer for millennia, and the bounty of societies that had settled became a new source of forage and predation to those who had not. Rather than following herds, some tribes would wander the outskirts of agricultural settlements and survive by stealing livestock or raiding grain stores - it was all the same to them: Food was food, whether it came from the Earth naturally, migrated with a herd, or was cultivated by someone else. As a result, the settlements were forced to develop means of defending their food surplus - i.e., concentrating it in one place, building walls around it, and guarding it. This was the origin of civilization, when haphazard riverside settlements evolved into cities as a means of defending their energy supply.
As the population expanded and density increased around these civilizations, the growing complexity of social relationships led to a process of economic and political specialization that has continued to increase ever since. Remarkably, the foundation of human civilization created an entirely new form of Root ecosystem, with human beings filling its niches and diversifying like another form of rain forest ecology. Like any ecology, the first cities grew in both extent and complexity until they reached equilibrium, where the available energy from agriculture and pastoralism was being optimally utilized.
At that point, further growth led to marginal conditions and social elements increasingly adapted to them - a new form of Spore. While older occurrences of Spore continued to exist in the form of nomadic raiders and tribal cultures distant from any civilization, the margins of organized societies began to "bud" with mobile elements who were connected to them without being fully integrated: Traders, exiles, and people marginalized by economic forces. These were people who had knowledge of civilization and interacted with it, but existed either by choice or necessity beyond its direct control. Just as with the hominids millions of years earlier, versatility and mobility were rewarded under these conditions.
While the core civilizations - Mesopotamia, Egypt, the Indus, and a few others - lived in a perpetual dream state, moving through the cycles of years, centuries, and millennia in relative prosperity with minimal social change, their Spore made contact with otherwise marginal settlements (or conquered them) and slowly transformed them into significant new civilizations.
These cities grew in areas that were not as rich as the first, but were also not especially difficult to cultivate: In other words, they were middle-case human ecosystems where society could achieve a measure of security while remaining somewhat generalized. They would not fall into the changeless rainforest dream like Egypt et al, but rather retain a degree of dynamism: Entire civilizations in a continuous Spore state.
In particular, Phoenicia and the Mycenaean Greeks were responsible for seeding large swaths of the Mediterranean and Black Sea coasts with new cities and tying them together with maritime trade. They were prosperous enough to form organized societies with surplus resources, but not so prosperous that they lost touch with the necessity to remain flexible - with the cultural intuition, in other words, for change and progress, even though these concepts had not yet been intellectually explored.
Ancient Spore reached its most active state in Classical Greece through the Hellenistic period, where at times it was an almost commonplace venture to raise funds for the foundation of a new city - sometimes in the midst of hostile indigenous cultures. The entire Mediterranean coast, including the Black Sea, was dotted with Greek city-states: Some survived and flourished, some were conquered and assimilated by non-Greek empires, and some were wiped out, but it was a highly successful and efficient expansion over a vast geographical area.
Spore activity was so promiscuous during this period that it was not uncommon for colonies to found their own colonies, and those in turn to found a third generation within the span of a single century. Human beings were more mobile, and in larger numbers, than at any other time prior to this, and set the foundation for what would ultimately become Western Civilization.
Meanwhile, Egypt continued much the same as it always had, and despite (or because of) its riches showed little interest in the outside world. They could have colonized the Mediterranean themselves, but never did - they were a Root civilization, and that is not how a Root civilization thinks. Their source of energy (food, in this case) is so abundant and reliable that it makes no sense to seek far-flung resources, so they just expand outward concentrically from the core until they run up against geographic or political obstacles. Unfortunately, by the time they reach a new resource base this way, Spore civilizations have already gotten there and are usually far more capable in warfare.
When Root civilizations grow, they expand outward into land contiguous with existing domains, and are uncomfortable or incompetent with trying to operate at a distance. To illustrate an example, Egypt was periodically invaded by Greeks for centuries beginning in the Mycenaean era, but it was so unaware of the world beyond itself that it had no idea who they were and never bothered to find out: They were just "Sea Peoples." Only being conquered by Alexander the Great in the 4th century BC finally opened their eyes to a broader world, and by then it was a moot point. The lesson is that, although Root is rich, its power wanes over time from lack of adaptability, and it is eventually overcome by quicker and more agile civilizations.
Once Alexandria became the center of the Greek world, it was no longer a Spore civilization: It had enveloped a Root, and increasingly saw itself in inwardly-directed terms with declining motivation for far-flung expansion. The actual Greek peninsula, although held in high regard for its history and academy, had become irrelevant to the civilization it had birthed: The Hellenized remains of the Persian Empire (primarily Anatolia and Egypt) were now its focus, since they were the overwhelming source of its agricultural output. So relatively little attention was paid to the borders of Greek civilization on the Italian peninsula - it was hardly a rich area, and the Italic peoples were thought barbarous.
Unfortunately for the Greeks, Rome was the epitome of the middle-case: Its immediate environment was neither wealthy nor poor; its geography neither wide open to invasion nor so forbidding as to deter movement; and as it was on a sizable peninsula, it came to be every bit as comfortable with naval operations as with moving deep within continental Europe. Every step Rome took on its ascent to Empire made it more mobile rather than less, building massive aqueducts to ensure the water supply, a robust network of roads raying outward into every conquered territory, and strong navies capable of crossing the Mediterranean to anywhere along its coast. It was the most extraordinarily potent Spore civilization ever seen, extending both its military reach and culture farther than Alexander had ever dreamed.
But this all began to change when the Empire encompassed Egypt, flooding the Roman economy with Root-level agricultural resources. This caused the population of Italy to explode beyond what the regional ecosystem could sustain, and made social stability in Rome itself dependent on regular grain shipments from Egypt. At this point it was no longer Spore, but a very precariously-extended Root that would spend the next millennium falling to pieces from West to East.
With most of their food/energy coming from the East, and political instabilities made worse by a tenuous food supply, it became clear that keeping the capital of the Empire in Italy was not feasible. Incessant barbarian invasions and social turmoil throughout the Empire meant that the seat of power needed to be within practical range of the energy base - i.e., it had to relocate Eastward. Once that was done, there was little systemic motivation to keep defending the West: It became a liability to the Empire rather than an asset, providing minimal returns while incurring substantial costs to defend.
The rest of that particular story and the ensuing Dark Age is outside the scope of this diary, as chaos is not very enlightening on this subject. Rather, my point is to show how organisms and ecosystems - including human civilizations - evolve in order to more closely approach and efficiently exploit the source of their energy. They do this by going through Root/Spore cycles, with each iteration exceeding the last: Each Root growing deeper, wider, and more complex, and each Spore becoming more effective at spreading farther and faster. At every point, on every fractal level of the system, energy is the key to understanding why these cycles occur and the shape they trace out over time.
Skipping ahead about 1,800 years, we come to the first major change in energy since the development of agriculture: The invention of the practical heat engine. The key point about a heat engine is that it doesn't matter how the heat is generated - so long as the operating temperature is achieved, the input energy will be transformed into mechanical work within the limits of engine efficiency. Prior to this point, there had been plenty of mechanical augmentations for human and animal muscle power - levers, pulleys, etc. - but technologies capable of entirely supplanting it (e.g., water wheels) had too many limitations to be broadly applicable. A heat engine, by contrast, can be carefully controlled, can operate in most weather, and is capable of delivering far more power.
Now, it's important to note that a heat engine is not a source of energy, it's just a machine that transforms energy into work. But once the technology was applied to transportation and manufacturing, fuel resources that were already in use (i.e., coal) radically expanded both the mobility and productive capacity of the human species. The global population nearly doubled between 1800 and 1900, and quadrupled the century after - increases that would have been insupportable without the improvements in agriculture and transportation made possible by the Industrial Revolution.
Heat engines became, and still are, ubiquitous: An internal combustion engine is a heat engine that uses gasoline as fuel; nuclear reactors use controlled fission of uranium to drive a common heat engine; oil, coal, and natural gas power plants drive heat engines; even most fusion power concepts involve directing the output energy into a heat engine in order to generate electricity. There is also solar thermal power, which focuses sunlight to create the heat that drives the engine.
In other words, the heat engine is technology that made general harnessing of energy possible, regardless of the source. It did for humanity's energy resources what the capturing of fire did for our diet - generalized it. Anything at all that can generate enough heat can drive a heat engine and power transportation or an electric generator. Nuclear fission, seismic venting (geothermal), burning of oil, burning of coal, burning of gasoline, burning of organic gases, burning of plant matter, plasma gassification, focused sunlight, etc. etc.
Of course, there are other means of driving machinery and/or generating electricity than heat engines: Most significantly, there are photovoltaic panels that directly translate sunlight into electricity. There are also passive turbines, such as those used in hydroelectric plants and wind farms - the passage of a fluid (water or air) over the blades turns the rotor that either powers a generator or results in direct mechanical work. Such turbines are the successors to the water wheels and windmills used prior to the Industrial Revolution, but it should be noted that photovoltaic technology is something genuinely new in the world: It did not exist outside of laboratories until the latter half of the 20th century.
Such is the energy picture of humanity today. But think about this, because it will play a central role in how I flesh out my model of the far future: Out of all the extant technologies identified above, two and only two do not ultimately come from the Sun - geothermal and nuclear - and their total theoretical potential is miniscule beside even one of the others. Beyond the coriolis effect, the energy harnessed by wind turbines comes from the Sun heating the atmosphere; the Sun drives the hydrological cycle that evaporates and precipitates water, resulting in the rivers and glacial melts that hydroelectric plants harness; the Sun's energy was photosynthesized into organic compounds that were concentrated over millions of years into coal; plants powered by the Sun fed the dinosaurs, the dinosaurs fed each other, and some of them became oil. Solar energy is stored in the plant matter we eat and the wood we burn.
Here is a simple diagram I've made to illustrate the relationship between these sources of energy. Note that the lengths of the lines do NOT mean anything - the diagram is purely intended to show an upstream/downstream relationship:
The Sun is the vast, overwhelming energy source for life on Earth, so if we "follow the energy" - if civilization pursues its energy pathway upstream - what does that mean for our future? What kind of shape will human civilization take as our societies transition to solar-based economies, and where will following the energy take us? I see the beginning of a long and awesome journey for our species.
END OF PART 1