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THOMAS MALTHUS. MALTHUSIAN AND NEO-MALTHUSIAN THEORIES. Who is Thomas Malthus and what did he predict?. What factors influenced Thomas Malthus’s thinking?. Thomas Malthus (1766-1834) lived in England during the British Agricultural and Industrial Revolutions:

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Thomas malthus




Who is thomas malthus and what did he predict

Who is Thomas Malthus and what did he predict?

What factors influenced thomas malthus s thinking

What factors influenced Thomas Malthus’s thinking?

Thomas Malthus (1766-1834) lived in England during the British Agricultural and Industrial Revolutions:

The British Agricultural Revolution (1700-1900):

  • Period of tremendous increase in agricultural productivity and net output, supported by advances in science, engineering and elementary botany.


  • As the revolution in industry progressed, machines became available that increased food production with ever fewer laborers.

    Population Increase: the population of England and Wales, which had remained steady at 6 million from 1700 to 1740, rose dramatically after 1740. The population of England had more than doubled from 8.3 million in 1801 to 16.8 million in 1851 and, by 1901, had nearly doubled again to 30.5 million.

    British Industrial Revolution: The agricultural revolution supported unprecedented population growth, freeing up a significant percentage of the workforce, and thereby helped drive the Industrial Revolution.

Thomas malthus

Based on his observations, what did Malthus conclude?Gross domestic product (GDP) refers to the market value of all goods and services produced within a country in a given period. It is often considered an indicator of a country's standard of living.

Thomas malthus

In An Essay on the Principle of Population, published in 1798, Malthus claimed that the population was growing more rapidly than the Earth’s food supply because population increased geometrically, whereas food supply increased arithmetically.

  • Today: 1 person, 1 unit of food

  • 25 years from now:2 persons, 2 units of food

  • 50 years from now:4 persons, 3 units of food

  • 75 years from now:8 persons, 4 units of food

  • 100 years from now:16 persons, 5 units of food

    Malthus’s reasoning: food production grows by ADDITION of more acreage into cultivation, whereas population grows by MULTIPLICATION of human beings.

    Malthus’s idea of geometric population growth is now commonly referred to as EXPONTENTIAL GROWTH.


Thomas malthus

Malthus argued that human population growth would eventually outpace people’s ability to produce food.

Thomas malthus

Malthus predicted that overpopulation and lack of food would lead widespread starvation and diseaseLooking that the numbers and J-curve of population growth, he figured that population was going to catch up quickly.

  • What ended up happening instead?

  • How could this be depicted on a graph?

Growth in population and food supply

Growth in Population and Food Supply:

  • What do the spikes in food supply represent?

  • What factors did Malthus fail to take into account?

Malthus s first assumption

Malthus’s First Assumption

  • Although Malthus foresaw the development of new agricultural technologies, he did not realize to what degree new technologies would increase food production.

    What factors increased food production and why?

Factors that increased food production starting in the 18 th century

Factors that increased food production, starting in the 18th century

  • Draining marshlands to grow arable crops.

  • Replacing low-yield crops, such as rye, with higher-yielding crops like wheat or barley.

  • Clearing woodland to create pasture

  • Growing turnips and clover for fodder, which helped to produce arable farms.

  • Growing turnips was important in reducing the area of fallow land (can grow turnips and weed at the same time).

  • Increasing the NITROGEN in soil by growing legumes, especially clover, increased nitrogen fixation in the soil.

Nitrogen fixation

Nitrogen Fixation

Atmospheric (unfixed) nitrogen is effectively unlimited (forming over 70% of the atmospheric gases), but this is not in a form useful to plants. To make nitrogen accessible to plants requires nitrogen fixation (conversion of atmospheric nitrogen to a plant-accessible form).

Additional developments to increase food production in 19 th century

Additional developments to increase food production in 19th century

  • More animal power was available and from the 1820s and 30s onward, machines improved the cutting and threshing of grains.

  • Agrarian capitalism influenced the organization and employment of the workforce, leading to better farm management and more efficiency.

  • Chemical fertilizers were introduced to increase crop yield.

Machines to improve cutting and threshing of grains

Machines to improve cutting and threshing of grains

  • McCormick reaper (machine that cuts grain):

  • Combine (reaps, threshes, cleans grain):



  • Organic fertilizers have been used for many centuries, whereas chemically synthesized inorganic fertilizers were only widely developed during the industrial revolution.

  • Inorganic fertilizer use has significantly supported global population growth — almost half the people on the Earth are currently fed as a result of artificial nitrogen fertilizer use.

Malthus s second assumption

Malthus’s Second Assumption

2. Malthus assumed that humans have no control over their reproductive behavior. He did not foresee that population growth would slow down because of




Use of contraceptives in kenya

Use of contraceptives in Kenya

Thomas malthus

Contraception use varies from country to country and is influenced by social, economic, religious, and cultural factors

  • In spite of 40 years of efforts to promote family planning, Pakistan’s population growth rate is still one of the highest in the world.

  • Reasons for not using contraception:

  • desire for more children

  • concerns about health (including side effects)

  • opposition of husband or mother-in-law

  • socioeconomic or cultural factors

  • lack of knowledge or availability

How education for women impacts total fertility rate

How education for women impacts Total Fertility Rate

Relationship between level of education and having children

Relationship between level of education and having children

Malthus s third assumption

Malthus’s Third Assumption

  • He did not recognize that famine is usually related not to a lack of food, but to the unequal distribution of food.

Because of unequal food distribution more food doesn t necessarily feed more people

Because of unequal food distribution, more food doesn’t necessarily feed more people

Food thrown away in the us

Food thrown away in the US

Neo malthusians


  • Even though Malthus’s assumptions were incorrect, some theorists (“Neo-Malthusians”) warn that a Malthusian catastrophe could still occur, resulting in a world-wide shortage of food.

  • Neo-Malthusians make three important points…

Neo malthusian concern 1

Neo-Malthusian Concern #1

#1 SUSTAINABILITY: When the population reaches 10 billion, there may be problems keeping up with food demand.

  • Soil erosion

  • Soil nutrient loss

  • Depletion of irrigation sources (water)

  • Soil salinization (salt accumulation)

Soil erosion

Soil Erosion

Relationship between farming methods and soil erosion

Relationship between Farming Methods and Soil Erosion

Loss of ground water

Loss of Ground Water

Soil salinization

Soil Salinization

Main cause of salinization

Main Cause of Salinization

  • The primary man-made cause of salinization is irrigation. River water or groundwater used in irrigation contains salts, which remain behind in the soil after the water has evaporated

  • IRRIGATION – artificial application of water to soil

Neo malthusian concern 2

Neo-Malthusian Concern #2

#2 INCREASING Per Capita DEMAND FOR FOOD: Globally, the amount of food consumed per person is rising.


Increased food consumption in mdcs

Increased Food Consumption in MDCs

The average First World citizen consumes around eight times the amount of food and resources that a person in the Third World does.

Thomas malthus

In 1970, the US had the 26th highest daily caloric intake.Thirty-three years later, the US had risen to #1 (>3600 calories per day).Our Canadian neighbors to the North haven't fared much better, rising from the 33rd most caloric country to #2.In countries that are shaded yellow, per capita calorie consumption is <1600/day.

Neo malthusian concern 3

Neo-Malthusian Concern #3

#3 Natural Resource Depletion:

Natural resources that are being depleted include:

  • Timber

  • Minerals

  • Energy

  • Other non-renewables



Deforestation of the amazon

Deforestation of the Amazon

Deforestation facts

Deforestation Facts

  • Rainforests once covered 14% of the earth's land surface; now they cover a mere 6%. The last remaining rainforests could be consumed in less than 40 years.

  • One and one-half acres of rainforest are lost every second.

  • Nearly half of the world's species of plants, animals and microorganisms will be destroyed or severely threatened over the next quarter century due to rainforest deforestation.

  • Experts estimates that we are losing 137 plant, animal and insect species every single day due to rainforest deforestation (50,000 species a year). As the rainforest species disappear, so do many possible cures for life-threatening diseases. While 25% of Western pharmaceuticals are derived from rainforest ingredients, less that 1% of these tropical trees and plants have been tested by scientists.

  • There were an estimated ten million Indians living in the Amazonian Rainforest five centuries ago. Today there are less than 200,000.

Beef the prime cause of deforestation in the amazon

Beef – the prime cause of deforestation in the Amazon

  • Between 2002 and 2003, Brazil overtook Australia and the United States to become the world’s largest exporter of beef. By now, its exports total well over 2.5 million tons annually, over 65 percent more than Australia, the next-largest exporter.

  • One typical four-ounce hamburger made from rainforest beef involves the destruction of 55 square feet of rainforest.

Animal agriculture and deforestation

Animal Agriculture and Deforestation

  • The United States imports roughly 200 million pounds of beef from Central America every year. Aside from the fuel used in transport, the grazing land for these animals comes from clear-cutting forests and rainforest.

  • Every minute of every day, a land area equivalent to seven football fields is destroyed in the Amazon basin. For each hamburger that originated from animals raised on rainforest land, approximately 55 square feet of forest have been destroyed.

  • In the United States, more than 260 million acres of forest have been clear-cut for animal agriculture.

    With increased per capita meat consumption, and an ever growing population we can only expect to see more deforestation in the future.

Beef consumption world wide

Beef Consumption World wide

Problems with inorganic fertilizers

Problems with inorganic fertilizers

  • Inorganic fertilizers are now produced in ways which theoretically cannot be continued indefinitely. Potassium and phosphorus come from mines (or saline lakes such as the Dead Sea) and such resources are limited.

  • Artificial nitrogen fertilizers are typically synthesized using fossil fuels such as natural gas and coal, which are limited resources.

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