Population and the environment Flashcards
What is population distribution?
Pattern of where people live
What is population density?
Number of people per km^2
Key physical factors affecting population density-Climate and farming
Rainfall, temperature, levels of solar radiation etc determine food productivity.
Many crops need temperatures of at least 5 degrees to grow whereas many livestock require crops in below 5 degrees.
Climate can also affect the level and nature of diseases, tropical diseases such as malaria and yellow fever will impact death rates and life expectancy.
Key physical factors affecting population density-soil quality
Soil fertility depends on texture, organic matter, pH and nutrients.
These determine agricultural output and type of farming system.
Fertility can be maintained with fertilisers leading to high population density however this can lead to consequences such as:
water pollution, eutrophication, increased greenhouse gas emissions
Areas with fertile soils often associated with densely populated areas however some soils such as volcanic or alluvial soils are prone to hazards
Key physical factors affecting population density-water
Key use is irrigation for food production but also used for hygeine and sanitation
Example - Egypt where 95% of its 80 million people live within 12 miles of the River Nile.
Key physical factors affecting population density-resources
High concentrations of resources such as fossil fuels = densely populated areas due to industrialisation
Even when these resources become depleted, industry leaves a legacy in these areas allowing other tertiary industries to flourish.
Impact of development processes on population size and distribution-Neolithic Revolution
Marked the transition from nomadic hunter gathers to agricultural settlements and civilisation.
Radical and important period of change in which humans began cultivating plants, breeding animals for food and forming permanent settlements.
Causes of the neolithic revolution
Earth entered a warming trend 14000 years ago
In the fertile crescent wild wheat and barely began to grow as it got warmer
Impact of development processes on population size and distribution-Industrial revolution
1760-1850 rapid rise in use of machinery and factories
Coincided with major population growth (Britain’s population doubled between these years)
Fertility rate case study-Niger
Worlds fastest growing population, at 6.6 children per women
Income per capita of just $600 per year
98% of population muslim - large families seen as prestigious
77% of girls are married before the age of 18
However teenage pregnancies are falling and many religious leaders are advocating for contraception use.
Fertility rate case study-Korea
On average a korean woman gives birth to her first child at 32.6 years old, which has increased from 30.2 years old a decade ago.
By 2100 korea’s population is estimated to fall by 54%
Post the 1950-53 Korean War the population doubled and in an effort to reverse this the government started encouraging couples to only have one child.
The demographic transition model
Stage 1: High fluctuating birth and death rates, total population low and stable
Stage 2: High birth rates - increase then decrease and level, Death rates have reduced significantly, total population is seeing natural increase
Stage 3: Birth rates declining significantly, death rates declining steadily, total population rising quite significantly
Stage 4: Both birth and death rates fluctuating slowly, total population still slowly increasing but starting to stabilise and level off
Stage 5: Death rate slightly higher than birth rates, population declining
Advantages/disadvantages of the DTM
Advantages:
Helps us to predict populations
Can be adjusted in the future
Can consider whether polices may be needed
Disadvantages:
No timescale - countries change at different rates
Based on research in Europe/North America
Assumes all countries will follow the same pattern
Does not offer reasons for the changes
Does not include the influence of migration, wars and pandemics
Assumes countries cannot move backwards
DTM - Niger
Physical links to DTM
Does not really match stage 2 or 3- surprisingly low DR due to young population and aid.
Physical factors affecting DTM:
Sahel reigon. South Niger has a tropical climate. The niger basin has been impacted by desertification due to climate change
This means an inability to grow crops which means low GNI (600$), leading to a high infant mortality rate therefore high BR
DTM - Niger human links to DTM
Sparsely populated in north due to sahel, lots of people in south, economy based on primary sector, subsistence farming, nomadic lifestyle
Conflict lead to high DR
98% muslim population and a culture of child marriage lead to high BR
DTM - Canada physical links to DTM
Physical - Arctic, Tundra and temperate climate zones
Central canada - rolling fertile plains, rich in mineral resources, largest coastline in the world
Ability to farm crops and trade meant earlier development- more investment in healthcare and education so low BR and DR
DTM - Canada human links to DTM
Tertiary economy, oil industry, multicultural society, welcoming to immigrants
Ageing populations- risk of high death rates and potentially natural decrease
Therefore Canada is allowing controlled migration to counteract this problem
Problems of a youthful population
Children tend to be working eg in farms and therefore not in education
Much more costly for the economically active through taxes
Government have to spend a significant proportion of their budget on the youthful population
Benefits of a youthful population
Can be seen as a potential asset for the country - do skilled jobs in the future, increased income in the future
Benefits of an ageing population
Grandparents play a huge role in childcare
Skillset to pass on
Enable the younger generation to work by providing childcare
Define demographic dividend
The demographic dividend is the economic boost a country gets when it’s working population outnumbers its dependants
There are more people who are economically active than dependents giving the country an economic boost.
Define migration
Migration is the movement of people across a specified boundary in order to establish a new permanent or semi permanent residence
It can take place locally, nationally or globally
Whats the difference between an asylum seeker and a refugee
Asylum seeker - Fled country due to fear of death/persecution. Seeking international protection but claim for refugee status not yet determined.
Refugee - An asylum seeker whose claim for asylum has been successful under the 1951 UN refugee convention and they are granted refugee status in a new country to live there permanently
Migration statistics
2/3 of all international migrants living in just 20 countries
1/3 originated from only 10 countries
Forced migration rising considerably in the last 10 years
Women and girls account for 48% of migrants
Few governments are seeking to lower the number of immigrants
Demographic implications on host country
Migrants in reproductive age groups means an increase in BR - balances population structure if previously ageing
Increase in economically active
Social implications on host country
Cultural advantages of new food, music, fashion
Pressure on maternal, infant healthcare and schools
Can give rise to ethnic and racial tensions
Migrants may settle in concentrated areas and become segregated
Political implications on host country
Some governments of overpopulated countries may encourage emigration to gain socioeconomic advantages or as an anti natal strategy
Processes to control immigration
Growth of RW racist organisations
Rise of anti immigration political parties
Resentment towards migrants
Economic implications on host country
Overcomes any labour/skill shortages
May provide a more competitive workforce in times of recession
Working migrants pay taxes
Increased size of workforce and reduced dependency
Pressure on jobs - may lead to unemployment
Environmental implications on host country
Pressure on land for development- roads, housing
Increased demand for energy, water and food puts pressure on natural
resources
Health implications at host country
Spread of communicable diseases being transmitted may become more likely - migrants move from areas of higher disease prevalence
Increased pressure on health services due to a rise in infectious diseases
Many developing countries lose doctors and other medically trained staff to countries that can afford to pay higher wages
Demographic implications on home country
lower birth rates - people of child bearing age leave
population structure - ageing population remain
loss of economically active
Social implications on home country
Loss of traditional culture
Breakup of families/communities
Economic implications of home country
Reduced pressure on food/energy/water
Less unemployment as fewer in workforce
Remittances sent home from migrants
Migrants develop new skills which they can bring home
Lose most educated/skilled from workforce
May create a dependency on remittances
Less agricultural/industrial production
Political implications on the home country
Pressure to redevelop an area in decline
May introduce pro natal polices or incentives to retain skilled workers
Environmental implications of home country
Farmland, buildings and sometimes whole villages may be left abandoned
Less environmental managment
Health implications of home country
Less pressure on health services however the most vulnerable may be left behind and remain at risk
Agricultural productivity
Measure of the economic performance of agriculture
Measured in terms of yield
Why has agricultural productivity increased
Past 55 year’s productivity has increased at an average of 2.5%-3% each year due to
Extensification - particularly in LICs where land is still available
Intensification - additional inputs such as machinery, fertilisers and pesticides have increased productivity
TFP - better/more precise use of inputs, based on scientific research and development
Total Factor Productivity (TFP)
ratio of agricultural outputs to inputs
How could TFP improve for crops?
Higher yielding crops
Drought/flood tolerant crops
More efficient and timely cultivation and harvesting practices
Disease resistance crops
Using technology that indicate precisely when and how much water and fertilisers to apply
How could TFP improve for raising livestock?
Using better animal care
Using better disasase management practises
Using higher quality animal feed
Breeding animals for favourable genetic qualities and behaviour
How has agricultural productivity changed
TFP increased from 0.2% in 1961 to 1.98% in 2001, and then decreased again to 1.28% in 2011
Input use has decreased from 2.2% in 1961 to 0.3% in 2011
Limiting factors of climate
Temperature - frost-free days
Wind storm - frequency
Precipitation - Water supply and evaporation
Limiting factors of soil
Water retention or leaching
Depth
Aeration
pH
Mineral content
Structure
Texture
Optima and limits model
The optimum conditions are the ideal growing conditions which maximise productivity.
Outside of the optimum, costs increase and yields decrease
Many crop types have been hybridised or modified by scientists to be tolerant to a wider range of climatic and soil conditions
Characteristics of polar climates
Winter temperatures often below -40 degrees
Summer temperatures range from -10 degrees to 10 degrees
Precipitation is generally less than 100mm per year
Ice caps
Tundra - permanently frozen permafrost
Distribution of polar climates
Above 66 degree latitude in the Northern and Southern hemispheres
Arctic - Greenland, Northern Canada and Russia
Antarctica
Population of polar climates
Occupied by 13.1m people spread between 8 countries
Population density of less than four people per square km.
Human activity in polar climates
Number of people living there has increased due to improved healthcare for indigenous populations and discoveries of vast natural resources (oil and gas)
This led to a large influx of immigrants
2/3 of the population in large settlements, however indigenous people still spread out
