Population and the environment: migration, resources and global population futures

international migrants

people who move from one country to another

refugees

people forced to flee their country and are unable to return due to persecution, conflict or changes to the environment like natural disasters

example of refugees

1.8 million people have fled South Sudan to neighbouring african countries to escape violence and hunger

Asylum seekers

people who have fled their country but not yet had their application to recognised as a refugee accepted

when can asylum seekers receive support

can only receive formal assistance and legal protection from the country they are seeking sanctuary from once it has been proven that their fear of returning home is well founded, once this happens they are given refugee status

economic migrants

people who move to another country to work

why does migration occur

push and pull factors

push factors

things that make people want to move out of the place they are in

pull factors

things that attract people to a new place

3 environmental push factors

• natural disasters

• impacts of climate change like rising sea levels

• desertifacation

4 socioeconomic push factors

• political instability, war or persecution

• lack of jobs or education

• lack of food

• economic decline

3 environmental pull factors

• more desirable climate

• better farming conditions

• fewer impacts of climate change like extreme weather event

4 socioeconomic pull factors

• better access to healthcare

• better job opportunities and higher salaries

• better schools and universities

• better quality of life

large scale migration example

over 5 million Syrian people have been forced to flee since war began in 2011

factors that affect the patters and processes of international migration

• governments

• physical barriers to migration

• cultural ties

• distance

• different timescales

government caps on immigration

some countries put a limit on the amount of immigrants they will accept like Japan who only let 47 refugees out of 4000 applications in in 2020 and no permanent low skilled migration

example of governments controlling where immigration comes from

EU citizens have free movement across Schengen Area of 29 countries but migrants from other countries have to go through approval processes

physical barriers to migration

dangerous seas like the English Channel

human barriers to migration

cost, relocation can be very expensive or things like ties to family or language barriers in host country

host country

the country immigrants are moving to

language, cultural ties or historical ties and immigration

many angolan migrants move to brazil because they both speak portugese or Windrush

migration timescales

can be permanent or temporary like economic migrants on short term visas for seasonal jobs like fruit picking and sheep shearing

what implications can migration have

demographic, economic, political, health, environmental and social on both the home and host country

3 demographic implications for home countries

• large scale migration causes population decline

• ageing population as working age people leave and elderly remain

• males more likely to leave causing a gender imbalance

2 economic implications for home country

• remittances

• brain drain when highly skilled people leave

2 political implications for home countries

• in countries loosing their workforce, government might try policies that discourage people leaving or attract migration into the country

• governments might introduce policies to increase fertility rates to stop population decline

2 health implications on home countries

• shortage of healthcare workers if they migrate elsewhere like UK doctors leaving NHS to go to Australia

• most vulnerable left behind when migration occurs which puts strain on existing health services

2 environmental implications for home country

• environment may improve if population declines due to reduced resource exploitation and farming

• buildings and farmland abandoned and fewer resources for environmental management

4 social implications for home country

• families split up

• better job opportunities as people leave vacancies behind

• less pressure on education services but funding could be cut as demand falls

• loss of culture or change of culture if migrants return home with different customs

3 demographic implications for host countries

• population growth

• population structure changes as most migrants working age people

• birth rates might increase due to influx of childbearing age people

2 economic implications for host countries

• expansion of workforce can fill vacancies not filled by native population which helps economy grow

• not enough jobs to go around

3 political implications for host countries

• anti immigration government policy

• rise of extremist organisations as people feel threated

• rise of anti immigrant political rhetoric can force normal politics rightwards

2 health implications for host countries

• large scale immigration can put pressure on healthcare services especially if migrants live in crowded poor conditions as they get sicker

• immigrants could spread infectious diseases from their home countries

2 environmental implications for host countries

• more houses, infrastructure and resources needed for influx of people so green spaces built on and more natural resources exploited

• larger amounts of waste generated that needs disposing which causes pollution

3 social implications for host country

• increased cultural diversity

• social tensions between local people and immigrants

• certain areas can become associated with immigrant groups so more move there when they arrive and diasporas form

population ecology

how populations interact with the environment

population growth dynamics

the study of how and why population sizes and structures change over time

what can population growth be limited by

environmental factors like climate, soil, geology and typography as they affect the availability of resources

also infectious diseases but most are curable

optimum population

the ideal number of people in an area, all resources are used to give the highest economic return per person and therefore the highest standard of living

overpopulation

when the population of an area becomes too high for the available resources the standard of living falls

underpopulation

if the population declines or is too low, there are too few people to use the available resources to their full potential so the standard of living is lower than it could be

optimum population can increase as

technology improves, like technology increasing crop yields so more food is available

optimum population depends on

population structure, like the dependency ratio being low meaning a higher population can be supported as there is more economic growth

carrying capacity

the largest population that an area is capable of supporting indefinitely

what determines whether we are living within carrying capacity

population size and amount of resources consumed by each individual

two outcomes if the population reaches carrying capacity

slow growing and rapidly growing

if a slow growing population reaches resource limit

the growth rate may decrease and population size becomes stable

if a rapidly growing population reaches resource limit

it might overshoot resource limit so population falls suddenly as death rates increase, population fluctuates around carrying capacity before stabilising

ecological footprint

a way of measuring the environmental impact of human activities by calculating the amount of productive land required to produce the goods and services that are being used

scales of ecological footprints

can be calculated at any level like an individual person, a group of any size or for a specific activity

what are ecological footprints measured in

global hectares

global hectares

the amount of land or average productivity that is required

ecological footprint of developed v undeveloped countries

developed countries have higher ecological footprints

ecological footprint of a person living in the UK

5gha

ecological footprint of a person living in Zambia

under 1gha

as the ecological footprint increases

carrying capacity decreases as it means more resources are required per person so the environment can support fewer people

current global rate of consumption

global population is using an equivalent of 1.6 earths a year so it takes the earth a year and a half to regenerate the resources we use in a year

UN projection for consumption by 2050

if the population reaches 9.6 billion by 2050, almost 3 planets worth of natural resources would be required to sustain current lifestyles

PRP model

population, resources and pollution model

what does the PRP model show

the relationships between people and the environment, natural resources provide goods and services to the human population but the acquisition and use of these resources causes pollution

population growth positive feedback loop

population growth leads to need for more food, food production increases, more food available, population increases further and more food needed again

resources positive feedback loop

increased population results in more extraction of fossil fuels, so more fuel is available to transport food to areas of deficit, malnutrition decreases and population increases

growing population negative feedback loop

growing population causes expansion and intensification of agriculture, increased soil erosion this decreases agricultural productivity so food production not high enough to support population so population decreases

resources negative feedback loop

increasing population, increased extraction and use of fossil fuels for energy, increase in greenhouse gasses causes climate change which reduces rainfall and crop yields so not enough food so population decreases

4 contrasting theories about the future of population change

Malthus

Neo-Malthusian

Boserup

Simon

who was Thomas Malthus

an economist from the late 18th and early 19th centuries who developed his population theory in 1798

Malthus 1798 theory

the population could grow more quickly than its capacity to feed itself

why did Malthus believe the population would grow more quickly than we could feed ourselves

• populations can grow exponentially

• food supply can only increase arithmetically (at a constant rate)

what did Malthus think would happen when population exceeded available resources

population size will be reduced by events like famine, war and disease

Basically, population will exceed carrying capacity and death rates will increase

limitations of Malthus’ theory

it is based on the idea that the rate of food production cannot increase rapidly however it actually has done thanks to advances in tech like the green revolution

Neo Malthusians

argue that rapid population growth is an obstacle to development and should be slowed down like through reducing birth rates via contraception

club of rome

an international think tank which used computer models based on malthusian ideas to model relationships between populations and resources in the 1970s

club of rome models’ predictions

continued rapid population growth would lead to a dramatic decline in economic growth within 100 years

club of rome recommendation for the future

humans can live indefinitely on earth only if they limit population growth and live more sustainably

other neo malthusian view

there are enough resources to support a bigger global population, the issue is how these resources are distributed

who was Esther Boserup

a 20th century economist who challenged the idea that there were limits human population growth

esther boserup 1965

however big the worlds population grew, people would always produce sufficient food to meet their needs

why did Boserup believe resources would always be able to keep up with population

farming would become more intensive as the population increased because population growth would encourage new methods and technology to be developed

evidence to support boserup

recent technology developments like GM, agrochemicals and hydroponics

limitations to Boserup’s theory

it is uncertain if food production can keep up in the long term

who was Julian Simon

20th century economist who argued that population increase was good for humanity

Simon’s theory

the ‘ultimate resource’ is the human mind and a growing population would produce enough intelligent people to solve the problems that arise so resources won’t run out

Simon’s views support who’s

Boserup’s as they believe that innovation will fix future problems

criticisms of Simon

conditions in some countries have got worse as the climate has changed

ozone

a gas mainly found in the upper atmosphere which forms a layer that absorbs harmful UV radiation from the sun

what has caused depletion of the ozone layer

chlorofluorocarbons CFCs which were used in aerosols and fridges until the late 20th century which caused the thinning of the ozone layer and a hole over Antarctica

UV radiation increases what 2 health conditions

• skin cancer

• cataracts

skin cancer and UV

UV rays cause genetic mutations in skin that has been exposed to the sun

2012 skin cancer deaths

55,000 deaths worldwide

cataracts and UV

when the lens of the eye gradually becomes more opaque causing blurred vision

how many people are blind due to cataracts

20 million

what percentage of cataracts are caused by overexposure to UV radiation

20%

treaty that delt with ozone depletion

Montreal protocol of 1987

goal of Montreal protocol

Phase out the production and use of ozone-depleting substances (ODS), especially CFCs chlorofluorocarbons

impact of the Montreal Protocol

The ozone layer is now healing, and it’s considered one of the most successful environmental treaties ever

ozone layer next 50 years

even though it is starting to recover, the damage is likely to persist for at least another 50 years

public health and climate change

temperature increase, changing patterns of precipitation and changing patterns of food production

How is climate change affecting temperatures in many areas?

Temperatures are increasing, leading to more frequent and intense heatwaves and warmer summers.

What is thermal stress and who is most affected?

Thermal stress is strain on the body due to high temperatures, increasing deaths in the elderly and those with cardiovascular or respiratory conditions.

How might climate change reduce some health risks?

Milder winters can reduce cold-related diseases and deaths.