Theories of Population Growth *

Malthus

• Predicted a pessimistic view on the dangers of overpopulation and claimed that flood supply was the main limit to population growth

• At that time, the world population was nine million. Malthus believed the population  increases geometrically (2,4,8,16,32etc) whereas food supply can only grow arithmetically (2,4,6,8etc) being limited by available new land.

• Food is essential for life but population increases faster than food supply.  Mathus predicted that the population would grow until it reached the limit of food supply, then there would be widespread poverty and famine.

Malthus evaluation

• Congo war over resources - 3mn deaths

• Reduced population growth as countries move through DTM

• Technological improvements such as irrigation - Rwanda 70% land productive for food

Malthus positive checks

• increased levels of misery (war, famine and disease)

• e.g. COVID

Malthus preventative checks

• celibacy, later marriage

• there has been a population explosion

• repeated wars and famine in Sahel region suggests population growth has outstripped food supply

• FAO sas that more than 800mn people are chronically malnourished

• UN says that by 2050 4.2bn people will be living in areas that cannot provide enough water for basic needs

Malthusian catastrophe

Malthus predicted that unless population growth was controlled life would end in misery, leading to what became known as a ‘Malthusian catastrophe’. Although his ideas originated 200 yrs ago, they received much support in the mid-20th century from demographers known as neo-Malthusians.

evidence to support neo-malthusian ideas

• the regular famines that occur in countries such as Sudan and Ethiopia

• the wars that are often fought over food, water and energy resources

• water scarcity - especially in the Middle East

evidence that doesn’t support neo-malthusian beliefs

• development of new technology

• opening of new land for cultivation

• development of irrigation systems which have allowed increased yields

• the Green Revolution - widespread introduction of high-yield crop varieties, pesticides, fertilisers etc

• the slow down in population growth as counties develop economically and progress to the latter stages of the DTM

malthus perspective

pessimistic and deterministic

malthus theory

population grows exponentially but food supply grows in linear

malthus implications

• there will be a time when there is not enough food to sustain the population

• the population will then exceed the carrying capacity

• as a result, population growth will stop due to a malthusian crisis or catastrophe - famine, disease or war

• these are known as positive checs as they increase the death rate

• preventative checks are factors which decrease the birth rate such as marrying later and choosing not to have children

• these limiting factors maintain the balance between population and resources

neo-malthusian / club of rome perspective

pessimistic and deterministic

club of rome theory

• supported and extended malthus’ isea

• modelled how rapid population growth becomes a ‘limit to economic growth’

• population checks should be introduced to reduce birth rates and conserve resources

club of rome implications

• population to rise until 2050 and then decline

• fast resource depletion from 2000-2050

• food supply declines from 2000

• industrial output and productivity declines from 2000

• pollution increases until 2030 then declines

boserup perspective

optimistic and possibilistic

boserup theory

population grows and stimulates innovation in technology so that food and resource supply keeps pace with population growth

boserup implications

• carrying capacity can sustain larger population

• farming to become more intensive - e.g. in EU in response to the EU Common Agricultural Policy

• green revolutions in agriculture - e.g. in Mexico, S/SE Asia

• biotechnological developments such as GM plants

simon perspective

optimistic and possibilistic

simon theory

the human mind is the ‘ultimate resource’ and so will always solve the problem of scarce resources

• will get more of the resource

• find a subsitute to the resource

• manage society to get the resource

simon implications

• population increase is positive for humanity

• resources will never run out

• technological innovation will reduce scarcity of raw materials and decrease their cost

• food and water quality will increase

• climate change may show flaws in this theory

boserup evaluation

• Biotechnology developments means there is 17% more food available per person compared to 1990

• Uneven distribution and political instability still leaves 5 million in Yemen relying on food aid

• Carrying capacity may not be improved in vulnerable areas such as India where 1 degree increase in temperature leads to 20% rice yield loss

since 1798 there have been many ways in which food production has increased

• land reclamation from the sea

• draining marshlands - bringing them into agri, productivity

• cross breeding cattle

• developing high yield varieties (e.g. rice)

• terracing of steep slopes

• creating artificial environments - e.g. greenhouses

• using sophisiticated irrigation techniques

• creation of new foods such as soya

• creation and extensive use of fertilisers/pesticides

• fish farming

20 marker notes

• Critical appraisal of Melthus’ viewpoints in terms of future population growth. For example, whilst there is certainly evidence to support the viewpoint in Sub-Saharan Africa, much of the globe is seeing falling population growth and innovation is improving our ability to cope with climate change

• Easter Island supports Malthusian ideas as the population was decimated as it used all its trees for firewood and building homes, meaning that soil erosion occurred and they were unable to grow enough food