Somewhere around 1.5 million years ago, give or take a hundred thousand years, someone in Africa made an amazing intellectual leap. They realized that fire could be used.
"J. W. K. (Jack) Harris, an archaeologist at Rutgers University, has discovered at the Kenyan sites of Chesowanja and East Lake Turkana areas of baked clay that date back to about 1.5 million years ago. These circular areas of baked clay test out to have been formed by quite limited fires of low temperature, unlike widespread spontaneous bush fires or high-temperature lightening strikes. Their circular outlines are different from the pattern of soil baking that results from a burning tree stumps. None of these sites have 'hearths' the stone-rimmed, ash-filled, and carbon-rich deposits indicative of habitual fire use-that archaeologists have discovered at later time horizons around the world." ~ Noel Boaz, Eco Homo, (New York: Basic Books, 1997), p. 180,
There are hearthlike arrangements of stones at Swartkrans, South Africa, dating from 1.6 million years. If these ancient sites represent control of fire, which is controversial, it represents an amazing increase in energy available to the human species over that available to our primate ancestors. Wildfires generally only reach 300 deg C. Controlled fire reaches up to 600 deg C. Interestingly, at Swartkrans, electron spin resonance indicates high temperatures.
With fire, one can use the energy for warmth, which is obvious, but less well known is the ability of cooked food to not only make the meat and vegetables tenderer, the heat also breaks apart the toxins many of our food contain, making them safe to eat.
"While the excavation and eating of yams possibly go back to the earliest fire-users (because they must be cooked), this tuber more than any other is likely to have become the staple for a distinctively new and eventually very successful lineage in Africa."
"Yams also have many useful by-products, which are known by contemporary, or have been used by, recent people. In southern Africa, two wild species are used to prepare a bait which immobilizes monkeys, while yam extracts can also be ingredients of arrow poison. In Southeast Asia, both birds and fish used to be stupefied with yam poisons and a yam shampoo was used to get rid of head lice. Learning that an underground root has all these toxic properties implies a very great and long-standing intimacy with the plant." ~ Jonathan Kingdon, Self-made Man, (New York: John Wiley and Sons, Inc.,1993), p.156-157
Speaking of a more recent group of people, who were very important in the history of energy, we see the effect on meat.
"An equally important technological advance was the growing reliance on fire. From the pattern of ashes left behind in Mousterian 'hearths,' Brace deduced that the Neandertals were earth-baking their food in shallow pits lined with fire-heated rocks and covered with soil. 'It seems abundantly clear that the Neanderthals of the Mousterian were cooking their food in the same way that the Polynesians still do...' he recently wrote. 'Meat cooked in such a fashion can become quite tender indeed, and in such condition it requires less chewing to render it [more] swallowable than would be the case if it remained uncooked." ~ James R. Shreeve, The Neandertal Enigma, (New York: William Morrow and Co., 1995), p. 51
By 800,000 years ago, there is clear unequivocal evidence for humans using the hearth, meaning that temperatures which they could create reached up to 600 deg C. But, 73,000 years agothe Neanderthals were about to make another grand discovery. They were the first coal miners.
"Charcoal analysis_the study of charcoal from archaeological contexts_is designed to reconstruct palaeoenvironment and human use of wood. At two prehistoric sites in the Causse du Larzac (France)_Les Canalettes (Mousterian) and Les Usclades (Mesolithic)_charcoal analysis has revealed specimens whose anatomical structure was abnormally compressed in transverse section. The authors conducted experiments to determine how the compression could have occurred. The result was the first evidence for lignite in Palaeolithic settlements. Lignite fragments in a hearth suggest local Palaeolithic people used it for fuel. The lignite could have come from major coal outcrops within 7 to 15 km of the sites. Coal use is otherwise unknown for Palaeolithic cultures in France, and its use at Les Canalettes during the last glacial is the oldest recorded instance. Coal may have been used for fuel primarily because wood became scarce during the last glacial."
I. Thery et al, Journal of Archaeological Science, v 23, n 4, July 1996, p509_512
Water boils at 100 deg C. For comparison, forest litter will ignite at around 210 deg C. Coal won't ignite until it reaches 300 degree C but it can, under some circumstances burn at temperatures as high as 1500 C. The rock that burns was an discovery of Neanderthals, probably because there were few trees in glaciated Europe
Thirty-two thousand years ago, coal was still being used.
"At Landek, on the left bank of the Oder at Ostrava Petrkovice in Czechoslovakia, the Brno Archaeological Institute carried out in the 1950s extensive investigations into the possible use of coal in the Palaeolithic settlement there. The site is on carboniferous sandstone and, according to Klima (1956), is one of the most important Palaeolithic sites in Silesia. Evidence for three huts was found and these were oval in shape having two hearths on the longitudinal axis of each making six in all. The hearths had been dispersed by solifluxion leaving particles of coal and coke in ash layers. In the ash, which was greyish black and 2.5 cm thick, were fragments of animal bones and mammoth ivory particles. The hearths were bowl shaped hollows in the ground. Numerous small lumps of haematite were also found and these had been baked to accelerate their decomposition into forms suitable for use as red pigment. A statuette carved in haematite is also found. This Gravettian site, over 30,000 years old, is situated near the outcrop of the Ostrava coal seams, according to Demek and Miroslave, and it is presumed that the settlers dug out coal and used it has a source of heat. According to Klima coal was also used for the making of ornaments at Kesserloch and Kniegrotte."
"Three settlement sites were excavated by Bren in the mining district of Kladno-Rakovnik. Here was found extensive evidence for the manufacture of bracelets of sapropelite, which is a form of lignite or brown coal. Bracelets were found in many stages of manufacture from rough pieces of sapropelite to half completed discs and the completed article. The tools used in manufacture were also found. In many La Tene graves in Czechoslovakia such bracelets have been found on actual skeletons." ~ R. Shepard, Prehistoric Mining and Allied Industries, (New York: Academic Press, 1980), p.231-232
But the discovery of coal expanded the energy available to the human race.
Giampietro and Mimentel.
"In subsistence societies, about 4 kcalories of exosomatic energy (basically in the form of biomass) are required per kcalorie of food consumed. Thus, the total direct cost of the daily diet is much lower in absolute terms, approximately 10,000 kcalories of exosomatic energy per capita (assuming a food supply of 2,500 kcal/day per capita). On the other hand, because of the limited access to fossil energy, the average return of human labor in subsistence societies is low. In such a system up to 5 hours of labor are required to supply the daily diet. In terms of human labor, in subsistence societies the daily diet costs 16 times more than in the U.S. food system. "
Mario Giampietro and David Pimentel (1994) "THE TIGHTENING CONFLICT:POPULATION, ENERGY USE, AND THE ECOLOGY OF AGRICULTURE http://dieoff.com/page69.htm
These authors point out that our diet today requires 35,000 kilocalories per capita vs. the 10,000 kilocalories per capita for the subsistence society.
Slavery for Cattle
The next great increase in human access to energy came with the invention of agriculture, generally believed to have taken place around 10,000 years ago. At that time, humans learned to domesticate animals. One horse, and presumably one cow, can output about 640 kilocalories per hour. Since the Amish work a horse 6 hours per day and no more, that means a horse can output more calories than a human requires. The base level metabolism of the human, the level below which the human starves is 1200 kilocalories per day. Normal healthy humans will take in 2500 kilocalories giving him the possibility of outputting 1300 kilocalories as useful work each day and not starve. The horse can output 3800 kilocalories in useful work per day. So, in addition to the 3 kilocalories of biomass burning, the Agricultural revolution immediately yielded an additional 4 kilocalories per animal.
Another way to view the energetics of these ancient societies, is to look at the calories per hour generated by the lifestyle. If a society is hunting large animals, then 10,000 to 15,000 kilocalories per hour can be generated via the kills. But, if one doesn't have large game to hunt, then hunting small game means that you can only get a up to 1,500 kilocalories per hour. Shellfish collecting yields 1-2,000 calories per hour and gathering wild plants only 700 to 1,300 kilocalories per hour. Subsistence farming gives 3,000 to 5000 kilocalories per hour. (Thomas Gale More, Climate of Fear, (Washington: Cato Institute, p. 32)
This was the catalyst which allowed society to blossom. Assuming that a person worked 8 hours per day at agriculture and that a person needs 2500 calories per day, a single farmer could provide food for between 10 and 16 other people.
It was about this time that people discovered a way to crystallize work. At first it was called gold; later it was called money. A farmer's output in the form of barley was weighed with a quantity of silver or gold. Effectively this equated calories to a quantity of metal. Today, if one uses the energy consumed by the United States, say in 2006 which is 2.322 x 10^16 kilocalories with the money supply at that time, M3, about 11 trillion dollars, we can divide and find that a dollar is the equivalent of 2,111 kilocalories per dollar. The money supply rises about a half a trillion dollars per year, so doing the same calculation for 2007 shows that a 2007 dollar is equivalent to 2,053 kilocalories per dollar. This works out to (drum-roll please) a 3% inflation rate for the dollar. Inflation may be measuring the energy content of the currency. When we print lots of dollars, it isn't merely that there are lots of them that causes inflation, it is that the energy content, the ultimate value of the currency is absolutely less.
All of the above energy additions made it possible for humanity to grow from an estimated 125,000 for H. erectus 1.5 million years ago, to an estimated 10 million hunter-gatherers 12,000 years ago and then to an estimated 162 million people living on earth in 400 B. C. (Henry C. Harpending et al, "The Genetic Structure of Ancient Human Populations," Current Anthropology, 34:4(1993):483-496, p. 494-495;David Pilbeam, "What Makes Us Human?," in S. Jones et al, editors, The Cambridge Encyclopedia of Human Evolution, (New York: Cambridge University Press, 1992), p. 2; L. Luca Cavalli-Sforza, Paoli Menozzi and Alberto Piazzi, The History and Geography of Human Genes, (Princeton: Princeton University Press, 1994), p. 68)
For the next several thousand years, the increase in population was fueled by the spread of agriculture to all ends of the earth. Nary a usable acre was left unplowed. But, while coal use increased, it didn't increase tremendously until the 17th century in England. Finding any quantitative information on coal use in the Roman era in either Rome or China is almost impossible. One thing is known, in 1770 to 1780 coal production in England, the coal production center of the universe in that time, was about 6.25 million tons. This fueled the industrial revolution, which gave humans control of huge calories with which to do work. For comparison this represents 41 trillion kilocalories, or 4.8 million kilocalories per capita in England (population 8.7 million in 1780). That is a huge quantity of energy with which to build the British Empire. Another way to look at it is the daily kilocalories that represents--13,310 per day per person. That means that at that time, when adding up horses, food and all, the Brits had around 23,000 kilocalories per day in 1770. One thing to remember, Britain at that time was THE developed country.
By 1900, the world was producing 924 million tons of coal and less than a billion barrels of oil per year. The population was 1.65 billion. All of this works out so that the average human had access to 19000 kilocalories per day per person in 1900.
Fast forward to 2008. Using the BP Statistical Review of World Energy and their conversion that a tonne of oil is equivalent to 10 million kilocalories, we find from all sources of energy, oil, natural gas, coal, hydropower and nuclear energy, the average human on earth has 46,000 kilocalories per day per person in extrasomatic energy; horses don't add much to our well being today. Effectively, every person on earth has the energy equivalent of 18-30 human slaves working for him. Here is the calculation
tonnes oil equivalent per year
kilocalories (10 million kilocalories per year
World population 6,602,274,812
This is low for a western society. In the US, each citizen has 212,000 kilocalories per day, which explains our high standard of living. In the next post, we will examine what happens as the energy runs out.