10.1: The Roots of Agriculture

The traditional story about agriculture goes something like this: initially, people were hunter-gatherers who lived short lives because they had to scrounge for food from what nature provided. At some point, someone in the tribe made the discovery that people could plant crops. This led to better food supplies, less work, and more leisure time to develop higher civilization. Geographers now know that this traditional story gets it backward in many ways. Hunting and gathering is a comfortable way of life, while agriculture is often an adaptation of necessity with significant negative ramifications.

To start, we need to define “agriculture.” The traditional story proposes that there is a significant leap forward – sometimes called the “agricultural revolution” or “Neolithic revolution” – when societies invent agriculture. However, it is more accurate to see agriculture as one stage on a continuum of intensification. Intensification refers to the amount of production per unit of land that is extracted for human use. Raising the level of intensification practiced by society requires increased manipulation of natural processes by humans. We can imagine a scale of intensification running from a wilderness where the only human activity is hikers picking a few berries to eat on their way, to a modern industrial farm that mass-produces corn.

Hunter-gatherers do not merely wander the landscape, picking up whatever food and other resources they happen across. Hunter-gatherer societies have the sophisticated knowledge of the plants and animals found in their territory, and when and how they can be harvested. While they are somewhat at the mercy of the earth’s cycles and the bioclimatic zone in which they live, hunter-gatherers do not just wait for nature to provide them with resources. Instead, they are astute observers of weather and the seasonal migration patterns of animals and growth patterns of plants, and they may deliberately manipulate the environment to encourage the production of the plants and animals they want.

Agriculture is defined as the cultivation of crops and efforts to breed better strains. Cultivate means “to care for,” and a crop is any plant cultivated by people. If society continues to increase its level of intensification, eventually it will find itself practicing types of production that we would recognize as agriculture. This is what occurred in different regions dating from 10,000 to 8,000 BC in the Fertile Crescent and perhaps 8000 BC in the Kuk Early Agricultural Site of Melanesia. There are various debates within the scientific community between human geographers, sociologists, and anthropologists as to why agriculture arose throughout these various locations, called hearths, around the world. Despite the debate, in each hearth area, the transition from a largely nomadic hunter-gatherer way of life to a more settled, agrarian-based one, included not just the cultivation and domestication of plants, but also the domestication of animals.

We can make some general assumptions that the cultivation of plants and domestication of animals was because of environmental or cultural push factors. It was likely a combination of both, since a variety of agricultural hearths were grown around the world and under different circumstances. From a climate science perspective, the likely catalyst of agriculture was that around 10,000 years ago, the earth was shifting away from the Pleistocene Ice Age and into a warming period called an interglacial period.

Still, the question lingers: why would a society intensify to the point of developing agriculture? Agriculture increases the output of food per unit of land. Farmers can get more food and other resources, and hence support more people, out of a given chunk of land than hunter-gatherers can. Agriculture is thus associated with a boom in population. However, if a population declines, a society may de-intensify to hunting and gathering.

10.2 Types of agriculture

Today, there are two divisions of agriculture, subsistence and commercial, which roughly correspond to the less developed and more developed regions. One of the most significant divisions between more and less developed regions is the way people obtain the food they need to survive. Most people in less developed countries are farmers, producing the food they and their families need to survive. In contrast, fewer than 5 percent of the people in North America are farmers. These farmers can produce enough to feed the remaining inhabitants of North America and to produce a substantial surplus.

Subsistence agriculture is the production of food primarily for consumption by the farmer and mostly found in less developed countries. In subsistence agriculture, small-scale farming is primarily grown for consumption by the farmer and their family. Sometimes if there is a surplus of food, it might be sold, but that is not common. In commercial agriculture, the primary objective is to make a profit.

The most abundant type of agriculture practiced around the world is intensive subsistence agriculture, which is highly dependent on animal power, and is commonly practiced in the humid, tropical regions of the world. This type of farming is evidenced by significant efforts to adapt the landscape to increase food production. As the word implies, this form of subsistence agriculture is highly labor intensive on the farmer using limited space and limited waste. This is a widespread practice in East Asia, South Asia, and Southeast Asia where population densities are high, and land use is limited. The most common form is wet rice fields, but could also include non-wet rice fields like wheat and barley. In sunny locations and long growing seasons, farmers may be able to efficiently get two harvests per year from a single field, a method called double cropping.

Another form of subsistence agriculture is called shifting cultivation because the farmers shift around to new locations every few years to farm new land. Farming a patch of land tends to deplete its fertility and land that is highly productive after it is first cleared, loses its productivity throughout several harvests. In the first agricultural revolution, shifting cultivation was a common method of farming.

There are two processes in shifting cultivation: 1) farmers must remove and burn the earth in a manner called slash-and-burn agriculture where slashing the land clears space, while burning the natural vegetation fertilizes the soil, and 2) farmers can only grow their crops on the cleared land for 2-3 years until the soil is depleted of its nutrients then they must move on and remove a new area of the earth; they may return to the previous location after 5-20 years after the natural vegetation has regrown. The most common crops grown in shifting cultivation are corn, millet, and sugarcane. Another cultural trait of LDCs is that subsistence farmers do not own the land; instead, the village chief or council controls the earth. Slash-and-burn agriculture has been a significant contributor to deforestation around the world. To address deforestation and the protection of species, humans need to address root issues such as poverty and hunger.

Pastoral nomadism is similar to subsistence agriculture except that the focus is on domesticated animals rather than crops. Most pastoral nomads exist in arid regions such as the Middle East and Northern Africa because the climate is too dry for subsistence agriculture. The primary purpose of raising animals is to provide milk, clothing, and tents. What is interesting with pastoral nomads is that most do not slaughter their herds for meat; most eat grains by trading milk and clothing for grain with local farmers.

The type of animals chosen by nomads is highly dependent on the culture of the region, the prestige of animals, and the climate. Camels can carry heavy cargo and travel great distances with very little water; a significant benefit in arid regions. Goats require more water, but can eat a wider variety of food than the camel.

Most probably believe that nomads wander randomly throughout the area in search of water, but this is far from the truth. Instead, pastoral nomads are very aware of their territory. Each group controls a specific area and will rarely invade another area. Each area tends to be large enough to contain enough water and foliage for survival. Some nomad groups migrate seasonally between mountainous and low-lying regions; a process called transhumance.

The second agricultural revolution coincided with the Industrial Revolution; it was a revolution that would move agriculture beyond subsistence to generate the kinds of surpluses needed to feed thousands of people working in factories instead of in agricultural fields. Innovations in farming techniques and machinery that occurred in the late 1800s and early 1900s led to better diets, longer life expectancy, and helped sustain the second agricultural revolution. The railroad helped move agriculture into new regions, such as the United States Great Plains. Geographer John Hudson traced the major role railroads, and agriculture played in changing the landscape of that region from open prairie to individual farmsteads. Later, the internal combustible engine made possible the mechanization of machinery and the invention of tractors, combines, and a multitude of large farm equipment. New banking and lending practices helped farmers afford new equipment. In the 1800s, Johann Heinrich von Thünen (1983-1850) experienced the second agricultural revolution firsthand— because of which he developed his model (the Von Thünen Model), which is often described as the first effort to analyze the spatial character of economic activity. This was the birth of commercial agriculture.

More developed nations tend to have commercial agriculture with a goal to produce food for sale in the global marketplace called agribusiness. The food in commercial agriculture is also rarely sold directly to the consumer; rather, it is sold to a food-processing company where it is processed into a product. This includes produce and food products.

An interesting difference between emerging countries and most developed countries (MDC) regarding agriculture is the percent of the workforce that farm. In emerging countries, it is not uncommon that over half of the workforce are subsistence farmers. In MDCs like the United States, the workforce that is farmers are far fewer than half. In the United States alone, less than 2 percent of the workforce are farmers, yet have the knowledge, skills, and technology to feed the entire nation.

One of the reasons why only 2 percent of the United States workforce can feed the entire nation has to do with machinery, which can harvest crops at a large scale and very quickly. MDCs also have access to transportation networks to provide perishable foods like dairy long distances in a short amount of time. Commercial farmers rely on the latest scientific improvements to generate higher yields, including crop rotation, herbicides and fertilizers, and hybrid plants and animal breeds.

Another form of commercial agriculture found in warm, tropical climates, are plantations. A plantation is a large-scale farm that usually focuses on the production of a single crop such as tobacco, coffee, tea, sugar cane, rubber, and cotton, to name a few. These forms of farming are commonly found in LDCs but often owned by corporations in MDCs. Plantations also tend to import workers and provide food, water, and shelter necessities for workers to live there year-round.

There has always been a delicate balance between how much of the Earth’s surface can be used for agriculture and the ability to produce enough food to sustain a growing population. Climate, terrain, groundwater, and soil composition create limits on what and where crops can be produced without major human adaptations to the landscape. New technologies and scientific knowledge have helped to increase the world’s cultivated land significantly. However, spatial variations in land resources like rainfall and temperature zones are still the most significant factors in determining what land is suitable for specific crops and types of agriculture.

10.3 Agricultural regions

The world’s cultivated land has grown by 12 percent over the last 50 years, mostly at the expense of forest, wetland and grassland habitats. At the same time, the global irrigated land has doubled. The distribution of these land and water assets is unequal among countries. Although only a small part of the world’s land and water is used for crop production, most of the easily accessible and (thus economic) resources are under cultivation or have other ecologically and economically valuable uses. Therefore, the ability to expand more cultivated land is limited. Only parts of South America and sub-Saharan Africa still offer a scope for some expansion. At the same time, competition for water resources has also been growing to the extent that today, more than 40 percent of the world’s rural population is now living in water-scarce regions.

The total global land area is 13.2 billion hectares (ha). A hectare is a metric system area unit and widely used land measurement for agriculture and forestry; it equals to 10,000 square meters. Of this, 12 percent (1.6 billion ha) is currently in use for cultivation of crops, 28 percent (3.7 billion ha) is under forest, and 35 percent (4.6 billion ha) comprises grasslands and woodland ecosystems. Low-income countries cover about 22 percent of the land area, but they account for 38 percent of the global population.

Land use varies with climatic and soil conditions and human influences (Figure 10.12). Figure 10.13 further shows the dominant land use by region. Deserts prevail across much of the lower northern latitudes of Africa and Asia. Dense forests predominate in the heartlands of South America, along with the seaboards of North America, and across Canada, Northern Europe and much of Russia, as well as in the tropical belts of Central Africa and Southeast Asia. Cultivated land is 12 to 15 percent of the total land in each category.

Cultivated land is a leading land use (a fifth or more of the land area) in South and Southeast Asia, Western and Central Europe, and Central America and the Caribbean, but is less critical in sub-Saharan and Northern Africa, where cultivation covers less than a tenth of the area. In low-income countries, soils are often more deficient, and only 28 percent of the total cultivated land is suitable for high yield crops.

It is also important to note that with overall growth in cultivated land, rain-fed croplands have declined slightly and irrigated cropland has more than doubled in the time between 1961-2008. This helps us to understand how humans have adapted the landscape for agricultural purposes.

Water resources available for irrigation are very unevenly distributed, with some countries having an abundance of water while others live in conditions of extreme scarcity or shortage of water. Also, even where water may appear abundant, much of it is not accessible or is very expensive to develop, or is not close to lands that can be developed for agriculture. Water scarcity has three dimensions: physical (when the available supply does not satisfy the demand), infrastructural (when the infrastructure in place does not allow for satisfaction of water demand by all users) and institutional (when institutions and legislation fail to ensure reliable, secure and equitable supply of water to users).

In some regions, particularly in the Middle East, Northern Africa, and Central Asia, countries are already using water resources more than what is available. The resultant stresses on ecosystems are increasingly apparent. It is now estimated that more than 40 percent of the world’s rural population lives in river basins that are, physically water, scarce.

Table 10.1: Types of Rainfed Production Systems and Regions

At the same time, in more developed countries, urban and industrial demand, has been growing faster than agricultural demand. Whereas in less-developed countries agricultural use remains dominant, in Europe 55 percent of water is used by industry. Water stresses occur locally across the globe, but some entire regions are highly stressed, particularly the Middle East, the Indian subcontinent, and northeastern China. Sub-Saharan Africa and the Americas experience lower levels of water stress. The quality of water is also impacted when run-off returns to the environment. In general, increasing population and economic growth combined with little or no water treatment have led to more negative impacts on water quality. Agriculture, as the largest water user, is a significant contributor. Key pollutions include nutrients and pesticides derived from crop and livestock management.

Rain-fed agriculture depends on rainfall for crop production, with no permanent source of irrigation. Rain-fed agriculture produces about 60 percent of global crop output in a wide variety of production systems (Table 10.1). The most productive systems are concentrated in temperate zones of Europe, followed by Northern America, and rain-fed systems in the subtropics and humid tropics. Rain-fed cropping in highland areas and the dry tropics tend to be relatively low- yielding, and is often associated with subsistence farming systems. Evidence from farms worldwide shows that less than 30 percent of rainfall is used by plants in the process of cultivation. The rest evaporates into the atmosphere, percolates to groundwater or contributes to river runoff.

Agricultural Economics

We know that climate and terrain place physical limits on what can be grown in specific locations on Earth. However, we must also take into account the geographic nature of the choices farmers make when deciding what to plant. Once subsistence farming intensifies to the point of producing more food than it requires to feed a family or local community, it makes financial sense for farmers to sell their excess products. In this shift from substance to commercial agriculture farms need to be profitable; and the more profitable, the better, so farmers carefully choose the crops and animals they raise. These decisions, in turn, affect what we eat.

You might be thinking, “Farmers do not control what I eat. I eat what tastes good”, but opinions vary wildly on the issue of taste preference from country to country, and even within the countries. Taste preferences for food vary within and across ethnicities, and even house to house among people that would seem alike in almost every way. Still, some trends characterize regions, in the US, and around the world, many of these foodways have roots in the local geography of a place. It is often said, “you are what you eat,” but geographers might add the rejoinder “what you eat depends on where you eat.” Family traditions determine what people eat, but understanding the evolution of those traditions requires an analysis of the spatial contexts in which they evolved.

Our ethnic heritage explains much of our taste preferences. European immigrants to the US established most American foodways. Europeans living 300 years ago would have readily recognized many American dietary staples, such as beef, pork, chicken, bread, pasta, cheese, and milk, as well as a number of the fruits and vegetables we commonly eat. Modern Americans also copy foodways borrowed from the indigenous people of the Americas. Less prominent elements of American’s diet are traceable to Asia and Africa.

Eating is a daily ritual, and as such, it is a deeply ingrained cultural routine. What you like to eat is probably not that different from what your parents and grandparents like to eat. The same was true for your grandparents, giving dietary habits exceptional staying power. This fact is part of the reason behind our obesity crisis. Our lifestyle has changed as rapidly as technology, and the economy has evolved, but many of our foodways are stubbornly resistant to change. The diets that served our ancestors who were farmers or laborers engaged in strenuous daily activities, provides too many calories and fat for a generation working and living in the information age. Cultural lag is the term that describes the inability of cultural practices to keep pace with changes in technological advancement. Numerous behaviors exhibit cultural lag, and culturally conservative regions exhibit a higher degree of cultural lag than places with more progressive tendencies

A sizeable portion of the American diet is purely American. We have adopted several foodstuffs favored by Native Americans. Maize, better known in America as “corn,” is perhaps the most American part of our diet. Domesticated by the indigenous people of Mexico thousands of years ago, it has proven a versatile and hardy plant. It is so versatile that today much of the world eats maize in some fashion. Most Americans know maize mostly as sweet corn. Americans eat sweet corn like corn on the cob, but also canned, frozen and fresh “off the cob,” and in a variety of dishes.

Less well known are maize varieties are known as field corn, although it is far more common because of its great versatility. Field corn is too hard to eat raw, so we modify it. Some of it is processed into cornmeal or cornstarch, which we in turn use to make things like corn chips, tortillas, and sauces. We also consume a lot of corn syrup and high fructose corn syrup (HFCS) made from field corn. Corn syrups are used as a sweetener, thickeners, and to keep foods moist or fresh. HFCS is an inexpensive replacement for cane and beet sugars, and therefore is the most common sweetener used in processed foods and soft drinks.

10.4 Making Sense of Land Use

Geographers are concerned with understanding why things happen in geographical spaces. Johann Heinrich von Thünen (1783-1850) was a farmer on the north German plain, and he developed the foundation of rural land use theory. Because he was a keen observer of the landscape around him, he noticed that similar plots of land in different locations were often used for very different purposes. He concluded that these differences in land use between plots with similar physical characteristics might be the result of differences in location relative to the market. Thus, he went about trying to determine the role that distance from markets plays in creating rural land-use patterns. He was interested in finding laws that govern the interactions between agricultural prices, distance, and land use as farmers sought to make the greatest profit possible.

The von Thünen model is focused on how agricultural is distributed around a city in concentric circles. The dot represents a city, and the first ring (white) is dedicated to market gardening and fresh milk production. That is because of milk products and garden crops, such as lettuce, spoil quickly. Remember that at the time von Thünen developed this model, there was no refrigeration, so it was necessary to get perishable produce to the market immediately. Because of this, producers of perishable crops were willing to outbid producers of less perishable crops to gain access to the land closest to the market. This means that land close to the community created a higher level of economic rent.

The second ring, von Thünen believed, would be dedicated to the production and harvest of forest products. This was because, in the early 19th century, people used wood for building, cooking, and heating. Wood is bulky and heavy and therefore difficult to transport. Still, it is not nearly as perishable as milk or fresh vegetables. For those reasons, von Thünen reasoned that wood producers would bid more for the second ring of land around the market center than all other producers of food and fiber, except for those engaged in the production of milk and fresh vegetables.

The third ring, von Thünen believed, would be dedicated to crop rotation systems. In his time, rye was the most important cash grain crop. Inside the third ring, however, von Thünen believed there would be differences in the intensity of cultivation. Because the cost of gaining access to the land (rent) drops with distance from the city, those farming at the other edges of the ring would find that lower rents would offset increased transportation costs. Moreover, because those farming the outer edges would pay less rent, the level of input they could invest prior to reaching the point of decreasing marginal returns (the term “marginal returns” refers to changes in production relative to changes in input), would be at a lower level than would be the case for those paying higher rent to be closer to the market. Therefore, they would not farm as intensely as those working land closer to the urban center.

The fourth ring would be dedicated to livestock ranching. Von Thünen reasoned that unlike perishable or bulky items, animals could be walked to the market. Additionally, products such as wool, hide, horn, and so on could be transported easily without concern about spoilage.

In von Thünen’ s model, wilderness bounded the outer margins of von Thünen’ s Isolated state. These lands, he argued, would eventually develop rent value, as the population of the state increased. Thus, in this fundamental theory, the only variable was the distance from the market.

Von Thünen was a farmer, and as such, he understood that his model did not exist in the whole of the real world. He developed it as an analytical tool that could be manipulated to explain rural land-use patterns in a world of multiple variables. To do this, Von Thünen relaxed his original assumptions, one at a time, to understand the role of each variable.

One of the more stringent assumptions in the Von Thünen model was his assumption that all parts of the state would have equal access to all other parts of the nation (with distance being the only variable allowed). He knew that this did not represent reality because already in his time, some roads were better than others, railways existed, and navigable water routes significantly reduced the friction of distance between the places they served. Therefore, he introduced a navigable waterway into his model, and found that because produce would be hauled to docks on the stream for transport, each zone of production would elongate along the stream.

Von Thünen also considered what would happen if he relaxed his assumption that production costs were equal in all ways except for the costs associated with distance from the market. Eventually, as he worked with his model, he began to consider the effects of differences in climates, topography, soils, and labor. Each of these could serve to benefit or restrict production in a given place. For example, lower wages might offset the advantages realized by being near a market. The difference in the soil might also offset the advances of being close to the market. Thus, a farmer located some distance from the market with access to well-drained, well-watered land with excellent soil, and low-cost labor nearby, might be willing to pay higher rent for the property in question even if it were a bit further from the market than another piece of land that did not have such amenities.

Von Thünen’s concentric circles were the result of the limits he imposed on his model in order to remove all influences except for distance. Once real-world influences are allowed to invade the model, the concentric land-use pattern does not remain in place. Modern technology, such as advances in transportation systems, increasingly complicates the basic concentric circle model. Recent changes, like the demand for agricultural products, also influence land-use patterns.

Changes in demand for farm products often have dramatic impacts on land uses. For example, when fuel production companies demanded dramatically increased quantities of corn to produce ethanol, and the price of corn rose accordingly, farmers responded by shifting from other food crops to ethanol-producing corn. As a result, land well suited for corn production now sells at premium prices (in Iowa and other corn-producing states, an acre of farmland may bring $12,000.00 or more). Currently, there is little extra farmland available upon which an expansion might take place. Therefore, changes in demand typically result in farmers shifting to crops that will bring the highest return.

The mid-Willamette Valley of Oregon provides another example of how changes in demand affect agricultural land uses. For years, the mid-Willamette Valley was the site of many medium-sized grain farms. The primary grain crops included wheat, barley, oats, Austrian peas, and clover. Also, farmers in the region produced row crops, orchard crops, hay, and grass seed. During the 1970s, in response to increasing demand, the price of grass seed increased dramatically. As a result, Willamette Valley farmers quickly changed their focus from the production of grain to grass seed. Soon after, several grain processing facilities closed, and grass seed cleaning, storage, and market facilities opened. There were other unexpected impacts, as well. For example, Willamette Valley grain farms once provided excellent habitat for Chinese pheasants. Pheasants eat grain, but they do not eat grass seed. When the grain fields disappeared, so, too, did the pheasants.

Like pheasants, people do not eat grass seed. On the other hand, oats, wheat, and barley are all food crops. Once a nation can meet its basic food needs, agriculture can meet other demands, such as the demand for Kentucky bluegrass for use on golf courses, lawns, and other landscaping. As incomes go up, the demand for food crops will grow proportionately. Eventually, however, when the demand for food is satiated, subsequent increases in income will no longer bring corresponding increases in the demand for food. This is the result of the elasticity of demand relative to changes in income. The measure of elasticity of demand is calculated by noting the amount of increase in demand for an item that a unit of increase in income generates. For example, luxury products such as expensive wines have a high elasticity of demand, whereas more common items such as rice have a low elasticity of demand. Once a family has all the rice they can typically eat, it will not purchase more as a result of more income. More income, however, would likely bring an increase in the consumption of prime cuts of beef or other such luxury foods.

New technologies in transportation, agricultural production, and the processing of food and fiber often have substantial impacts on the use of rural land. Technological changes mainly influence transportation. For example, the construction of the rail lines that connected the Midwestern United States with the market centers of the East made it possible for farmers in Iowa, Illinois, and other prairie states to improve their profits by feeding the corn they grew to hogs which they then shipped to the markets in the east. This is because the value of a pound of pork has always been far greater than the value of a pound of corn. Thus, by feeding the corn to the hogs, and then shipping the hogs, the farmers could earn greater profits because the shipping costs of their product were lower. In a sense, the farmers were selling corn on the hoof. Without easy access to railheads, this profitable agricultural scheme would not have been possible.

Of course, some folks have specialized in selling corn after it has been distilled into a liquid form. When the sale of alcohol was illegal in the USA, the transport of “liquid corn” was made easier when, in 1932, Henry Ford introduced the Ford V8, thereby enabling “Moonshiners” to move their product from hidden distilleries to waiting markets without being caught by the police. Additionally, “moonshiners” became expert mechanics who could turn a standard 60 horsepower V8 into a powerful, fast, agile machine. People who specialized in modifying these stock cars became pioneers in NASCAR racing.

Over the years, improvements in technologies have tended to drive down the relative costs associated with shipping farm produce. Furthermore, inventions such as refrigerated rail cars and trucks have eliminated some of the land- use constraints that once limited the locational choices of farmers who produced perishable goods. Less expensive haulage costs, decreased transit times, and better handling and processing methods have all served to make transportation systems more efficient and, hence, less expensive.

In theory, this should serve to reduce the importance of distance relative to other non-distance factors. Consider how far from the market a producer of fresh vegetables could locate in the early 19th century. The lack of all-weather roads and reliance on the transportation conveyances of the time (human and animal power) dictated a production location within a few miles of the market. The creation of all-weather roads that could be traversed by a horse and wagon, however, changed the situation. Without the roads, fresh vegetable growers would have been forced to pay high prices for land very near the market. With the roads, they were able to use less expensive land and still get their crops to market before spoilage made it impossible to sell them.

If the creation of an all-weather road made such a difference in land uses, imagine the impacts of the refrigerated aircraft now used to deliver loads of fresh flowers. Currently, many of the fresh flowers sold in US supermarkets come to the United States from the Netherlands via giant jet transport aircraft. This technology has significantly altered the importance of distance relative to the production of fresh flowers.

10.5 Population and Food Production

Recall that English economist Thomas Malthus (1766-1834) proposed that the world rate of population growth was far outrunning the development of food supplies. Malthus proposed that the human population was growing exponentially, while food production was growing linearly. Below is an example:

• Today – 1 person, 1 unit of food
• 25 years from now – 2 persons, two units of food
• 50 years from now – 4 persons, three units of food
• 75 years from now – 8 persons, four units of food
• 100 years from now – 16 persons, five units of food

During Malthus’s time, only a few relatively wealthy countries had entered Stage 2 of the demographic transition model high population growth. He failed to anticipate that relatively emerging countries would have the most rapid population growth because of a medical revolution. Many social scientists and even environmentalists are strong supporters of Malthus’s hypothesis of the coming global food shortage and are taking it several steps further. Human population growth and consumption may be outstripping a wide variety of the earth’s natural resources, not just food production. Billions of people may soon be engaged in a search for food, water, energy, and resources. These days, technology is allowing us to convert food into a fuel called ethanol. In the United States, large amounts of corn are being used to create biofuel as a way to remove ourselves from our addiction to oil. This has caused global corn prices to rise dramatically. Wars and civil violence will increase in the coming years because of scarcities.

Others discredit Malthus because his hypothesis is based on the world supply of resources being fixed rather than flexible and expanding. Technology may enable societies to be more efficient with scarce resources or allow for the use of new resources that were once not feasible. Some believe population growth is not a bad thing either. A large population could stimulate economic growth and, therefore, the production of food.

Marxists believe that there is no direct connection between human population growth and economic development within an area. Social constructs of hunger and poverty are the result of unjust social and economic power structures through globalization, rather than because of human population growth.

So even with a global community of 7 billion, food production has grown faster than the global rate of natural increase. Better growing techniques, higher-yielding, and genetically modified seeds, and better cultivation of more land have helped expand food supplies globally. However, many have noted that food production has started to slow and level off. Without new technology breakthroughs in food production, the food supply will not keep up with population growth.

The third agricultural revolution, also known as the Green Revolution, has been in response to these fears of a Malthusian food crisis. The Green Revolution consists of improvements to agriculture brought about by the application of modern scientific methods to the development of new crop varieties and agricultural inputs. The technologies of the Green Revolution first made their mark in the United States, but the term is most commonly used about their extension to farmers in developing countries.

Taking up Green Revolution technology involves adopting a whole package of inputs — improved seeds, new fertilizers, and new pesticides and herbicides, all of which have been designed to work together. The improved seeds were created through selective breeding and hybridization. The fertilizers and pesticides are composed of artificial chemicals designed to provide just the nutrients that crops need and to target their main pests and weeds. The Green Revolution produced dramatic gains in crop productivity where it was implemented, in some cases doubling or even tripling yields. Norman Borlaug, the agronomist who was the guiding force behind the Green Revolution and one of its most prominent spokespeople, was widely hailed as a hero who saved millions from starvation and won the Nobel Peace Prize.

There are many critics of the Green Revolution. While acknowledging some of the gains in the total food supply, these critics argue that the Green Revolution has several critical shortcomings. The health critiques raise concerns about whether the Green Revolution crops are safe to eat. This concern is particularly salient with respect to genetically modified organisms (GMOs). While tests have generally shown GMOs to be safe to eat, critics worry that modified organisms could trigger adverse reactions in people, for example, if a person with a peanut allergy ate corn that had a peanut gene spliced into it. There is also concern that work on improving crops has focused on boosting the size and appearance of fruits, kernels, and more, at the expense of making them less nutritious. Finally, health may be impacted by the growing style of Green Revolution crops. The Green Revolution aggressively suppresses any organism in the field that could compete with the main crop. However, for many poor farmers, “weeds” are an important supplementary source of food. Ironically, adding vitamin A to rice through genetic modification is proposed as a solution when the vitamin A deficiencies that it will fix were caused in part by a loss of leafy green “weeds” to Green Revolution herbicides.

Environmental critiques raise questions about whether Green Revolution agriculture is good for the wider environment. There are several ways in which the environment could be affected. First, the successful use of Green Revolution technology often requires increased use of water. This can deplete water supplies in dry areas (and lead to demands for environmentally-disruptive dams to increase the water supply). Pesticides, herbicides, and fertilizers frequently run off the farm into streams, with adverse effects on downstream ecosystems. Green Revolution farming can also, in some cases, pollute and deplete the soil, meaning that the gains in productivity will not be sustainable. There are also concerns about the heavy use of pesticides and herbicides, leading to the evolution of chemical-resistant super-bugs and super-weeds. Green Revolution farms can further exacerbate the problems of mono-cropping, converting large areas to farms with very low biodiversity and thus increasing susceptibility to disasters (weather-related, pest infestations, etc.). In the case of GMOs, a major worry is that modified genes will spread beyond the field. Wind and insects can carry plant pollen into neighboring non-GMO fields and non-farm areas. If the plants that receive the pollen cross-breed with the GMOs, the modified gene may become established off-farm, with potentially ecological severe consequences depending on the nature of the gene.

Social critiques center on the economic system that farmers become a part of when they adopt Green Revolution technology. Traditional agriculture was largely self- contained. Farmers produced their inputs by saving seeds from previous harvests to plant next year, by collecting their natural fertilizers, and by using their household labor to till the fields. However, the improved seeds and the package of chemical inputs that make up the Green Revolution cannot be produced on the local farm. They have to be mass-produced by large agribusiness companies and then sold to farmers. Farmers then become dependent on companies like Monsanto to buy their inputs and sell their products. The contracts that farmers sign with these companies often put small farmers at a disadvantage. Depending on the arrangements made by the farmers, they may then become highly dependent on the international agricultural market — meaning that global shifts in prices for both inputs and farm products can determine their ability to make ends meet.

An emerging trend in agriculture, which is in some ways opposed to but in other ways parallel to the Green Revolution, is the rise of organic agriculture. Organic agriculture is agriculture that avoids the use of “artificial” chemical inputs and genetically modified crops. The organics movement originated as an attempt to avoid the problems arising from the Green Revolution by creating a farming system that works in harmony with the land. This original vision of organic agriculture is reflected, for example, in community supported agriculture programs, which usually practice organic farming. In community supported agriculture, customers buy a “share” or subscription at the beginning of the growing season, then receive a portion of whatever produce the farm manages to grow. This system is meant to spread the risks of farming between farmers and consumers, create a closer bond between the farmer and consumer, and make organic agriculture more profitable. As the popularity of organic food has grown, organics have become big business. Major corporations now coordinate the production of organic ingredients all over the world. Due to the diversity of techniques and differing demands of different crops, there remains much controversy over how well organic farming achieves its goals of reducing its ecological footprint and improving consumer nutrition.