So why study the relationship of humans to their environment? The first week's readings offer some not-so-subtle clues. According to Marvin Harris, much of the forms human societies assume comes from the material limitations they face. Early forms of states owe to ability to produce an agricultural surplus, the ability to coerce people into working to produce that surplus (being surrounded by a vast desert helps here ... ), etc. Human settlement follows patterns, as this satellite image shows. What sorts of patterns?

While Harris' article talks mostly about the influence of the environment on humans, it also touches on the impacts humans have on their environment. The Kates and Harrison articles focus on this aspect as well. Humans have likely been around as a species some 150,000 years, according to the most recent research from fossil records. The first evidence of settled agriculture is about 10,000 years ago, and we call this the Neolithic Revolution (actually animals were domesticated before the cereals). As Kates et al. point out, although there were some exceptional societies that managed to overshoot their immediate environment's carrying capacities and wend their way into the annals of exctinct civilizations, for the most part enduring human societies have learned, by necessity, to live in some state of near-harmony with nature. This all began to change radically some 300 years ago--1/500 or .2% of the time humans have been on the earth. The POET model is a useful conceptual way of thinking about dramatic transformations in the relationship of humans to the environment.

One of the first subdisciplines in sociology included theorists who were attempting to understand and explain what drives social change in human societies. Karl Marx is a good example of this. He essentially says that human societies develop and transform because of conflicts between different social classes, which are defined based on who owns the important means of producing a society's 'goods' (i.e., the land, labor and capital), and who performs the actual labor. So in tribal societies with little surplus wealth, there may have been little difference. As long as resources were abundant, there were plenty for whoever needed them for their family's or clan's survival. Scarcity or surplus could change this, and make resources more valuable, and more likely to be claimed by specific individuals or groups--likely those with the most power. In feudal society we had the peasant class, which cultivated the food, and the lords or ruling class, which protected them and provided them with a fairly harsh existence in return for growing the food. Then comes capitalism, where owners of land, labor and capital employ workers, who are paid a wage that reflects only part of their labor--some remainder goes to the owners in the form of profit, which they reinvest and can use to expand their wealth and enterprise(s). Marx said that within capitalism are the seeds of its destruction--competition may lead to overexploitation of the work force in order to cut costs and maintain profit levels, and left unchecked this could lead to (insert gasp here) . . . socialism. Socialism is a more redistributive form of society, and its logical conclusion is communism, where people govern themselves, and as Marx said, is based on the principle 'from each according to his ability, to each according to his need.'

So Marx says class conflict drives social change. Another theorist, anthropologist Leslie White, says that the predominant source of energy in a society is the driving force. We've moved from human power, to animal power, used wood, then charcoal, and then discovered coal. Each of these changes has represented a transition to a more concentrated form of energy. Coal was the first fossil fuel (petroleum and natural gas are the other fuels we classify as fossil fuels), and these fossil fuels generally come from where (keep in mind the ultimate source of most all of our energy)?

Imagine seeing the world 350 years ago, and looking at how it has been transformed since. Forests cut (loss of forest cover), topsoil lost (topsoil takes hundreds of years to form), air polluted, waterways as dumping grounds for industrial effluents, parts of the ocean are essentially dead from pollutants . . . large urban areas with millions of automobiles, congestion, steel, glass and concrete, ringed by bucolic suburban settings, gated communities, where many of the cars sleep. How did this transformation take place in such a short period of time? How have humans reacted to these transformations? What did societies in the past do when they were overexploiting their resources bases, putting their wastes where they live? These are the issues we'll discuss in this class.

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Big processes--how did we get here?

We mentioned the neolithic revolution. The authors talk about hunter-gatherer societies, and their livelihoods. Our understandings suggest that in many cases, men were largely responsible for the hunting, and women for the gathering. The men's food supplies were less certain, and clans relied on the women's knowledge of plants and the landscape and their ability to provide a steady source of food that could be supplemented by the protein of animals caught by the men. These groups had to understand natural cycles, fruiting cycles, animal migrations and behaviors, etc., in order to survive. It was a means of subsistence that required fairly large areas of land. From the film we saw, a clan of Bush people in the Kalahari would require some 150 square miles to support itself. Childbirth and childrearing is a problem, becuase the clan never stays in one place for very long. Children may have nursed longer, and this would have reduced fertility rates. Also, it's pretty difficult to carry much stuff around when you're on the move. But despite these difficulties, studies of contemporary hunting and gathering societies suggest that their practitioners actually enjoyed a fair amount of leisure time.

So there has been lots of speculation as to why, some 10,000 years ago according to the fossil record, we see the first signs of sedentary human settlements. Why did people begin staying in one place, rather than moving around? It could have been because of some natural calamity, such as drought and famine. It could have been because of increasing population and pressure on the resource base. Maybe it was because people began to see the benefits of staying in one place. Clearly the satellite photo suggests that once people began sedentary settlements, they chose first areas rich in diversity and resources--near rivers, along coastlines, in warmer climates, where soils were fertile, etc. It could have been a combination of some of these factors. People could have chosen the extensive route--that is, gone out in search of other fertile areas to settle. But many chose the intensive route--increase the amount of production per unit of land. Agriculture represents organized energy capture, and energy is what keeps organisms and their species alive. As the film said, 1/2 square mile of cultivated area could support the same number of people as 150 square miles used by hunter-gatherers (although this likely doesn't address the other needs of a settled community, such as building materials, water provision, fuel of some sort such as wood, clothing where warranted, etc.).

The authors suggest, though, that humans were forced into adapting to a sedentary lifestyle. Perhaps they knew about the possibilities of agriculture or animal husbandry, but only began to exploit these when it was absolutely necessary. Both require large amounts of energy, and both can transform the landscape.

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In the fossil record and through history we have evidence of societies that overexploited the resource base and disappeared, or whose numbers were drastically reduced. Mesopotamia was once considered the fertile crescent of civilization, but now it is a desert because irrigation and evaporation brought salts to the surface, rendering the soil unfit for agriculture. Fortunately, they had oil underneath (or maybe not so fortunately these days ... ). The cedars of Lebanon were dessimated for use in shipbuilding and construction by various civilizations. The Mayan civilization in MesoAmerica was reduced to a shell of its former self, speculation suggesting this was largely the result of tropical deforestation and soil erosion. There are authors who suggest that Europe was nearing carrying capacity, and many areas had undergone massive deforestation (wood being the main fuel source) about the time that explorers 'discovered' the New World (this was essentially an extensive strategy of finding new resource bases to exploit).

So let's skip forward to the Industrial Revolution. How has it changed the earth, and humans' relationship with it? We can think of the Industrial Revolution as a technological revolution. Fossil fuels--coal, oil and natural gas--represented increasingly concentrated forms of energy, whose exploitation merely awaited the development of technologies to take full advantage of them. We've done that and more in the industrialized world.

Another big process has been an agricultural revolution. From human power to animal power, and then to mechanization and chemical intensive agriculture, we have managed to produce much larger quantities of food on a given parcel of land. Did this allow the population to grow from some 1 billion in the 1700s to over 6 billion today (1/3 of that in China and India)?

Population growth since 1750

source: Population Reference Bureau estimates and UN (medium series) long-range projections of 1992

Or did the population growth necessitate different forms of production? In other words, did resource pressures force people to try to grow more food on less land (remember the POET model ... )? As for processes such as the agricultural revolution, we are indeed in the industrial world growing more food on less land. However, there are a few qualifications:

1. As Barry Commoner said, 'everything is connected to everything else.'
2. He also said, 'there are no free lunches.'
3. The first law of thermodynamics states that 'energy can neither be created, nor destroyed.'
4. The second law addresses what happens when energy is transformed from one for to another as it is used by humans, plants or other organisms. The order we create is matched and exceeded by disorder somewhere else. This is called 'entropy.' Essentially, using energy often means losses at different levels of transformation--we eat food, and our bodies use it and give off lots of heat--energy tends to eventually be converted into less usable forms, and heat is usually dissipated into the atmosphere. Our body heat may help keep us warm under a well-insulating down comforter or in a sleeping bag. One million cars in a large city can give off more heat and carbon emissions that can have much greater local, regional, even accumulatively global effects.

What does this have to do with agriculture? The gains in productivity were not free. They required intensive mechanization, a great deal of social organization and corporate investment, and even more fossil fuels to run tractors and machinery, produce inorganic chemicals and pesticides, etc. Fossil fuels take millions of years to produce, through a combination of heat and pressure and time of long-dead plant and animal material. They are not an unlimited supply, and their use in mass production for mass consumption is not sustainable. They basically add a great deal of carbon into the air from organisms that had accumulated over the millennia.

One of the driving forces behind industrialization was capitalism. If we think of industrialization as a technology revolution, capitalism was an economic revolution. Capitalist societies organize production factors--land, labor and capital--in much different ways. Private property is important, so that people know if they make an investment, they can reap the benefits. Also important are markets. Decisions have to be made about purchasing land, investing in capital, equipment, a labor force, etc., and markets help investors determine how to allocate money. The bottom line is of course profit in a capitalist system. Combine capitalism with a population that has increased six fold in 300 years, and with an industrial system that allows for mass production of goods, in fact necessitates the mass production of goods since no longer are we all living on the farm and growing our own food (we have very specialized divisions of labor and depend on markets and income to get the things we need), and you can see how the scale of transformation of the natural environment has expanded dramatically in the last 3 centuries.

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Human exemptionalism?

But there's something to keep in mind . . . humans are a species, and if we can agree that they are not exempt from natural laws, such as the first two laws of thermodynamics mentioned above, then there is no reason why we as a species need to persist on the earth. In fact, if the history of the earth were a clock face and represented by a 24-hour period, humans showed up about 15 seconds before midnight.

If we are using our resources unsustainably as a set of societies, what's in store for us? Check this out:

• Footprint: how many hectares are needed to support current consumption patterns (in other words, it's taking resource consumption and representing it as an equivalent amount of land)
• Per capita footprint: how many hectares per person are needed
• Hectare: equals about 2.5 acres

In other words, the average American citizen uses 20 times the resources of the average person from Bangladesh. Some more evidence:

• 25% of world's energy comes from coal, 41% from petroleum; 90% of global commercial energy comes from fossil fuels.
• In the 1990s, world CO2 emissions increased 7.5% (they're going up, not down);
• U.S. carbon emissions increased 13% in the 1990s (it had pledged a 7% decrease by 2010 as a signatory of the Kyoto Protocols under the Clinton Administration, but President Bush has pulled out of that treaty);
• In 1997, the U.S. emitted 1/5 of greenhouse gases contributed to the atmosphere by human activity. The three major greenhouse gases are CO2, methane and nitrous oxide.
• World CO2 emissions are increasing (Largest increase: Thailand, South Korea, Taiwan--these are development success stories … models of how countries are supposed to grow their economies. What does this suggest?)U.S. auto fuel efficiency hasn't improved since the 1980s (mainly because of the growth in SUV, Sport Utility Vehicle, sales).

Are we going to be forced into an 'extensive' strategy? We're running out of planetary resources for that. An 'intensive' strategy of increasing production? We do that, yes, but as I've mentioned, it takes energy and resources to intensify and get more production out of a given amount of resource.

Another informal rule of ecology:

Mother Nature bats last.