Population and the Environment (Condensed)

Population density

the average number of people living in a specified area

Population distribution

the pattern of where people live, at all scales

Population density

the average number of people living in a specified area

Population distribution

the pattern of where people live, at all scales

what are the elements in the physical environment which determine population growth?

-climate

-soils

-water supply

-geology and other resource distribution

how does climate determine population growth?

-determines the food productivity (e.g rainfall, temperature, wind velocity...)

-determines how many people can be supported in area

-can drive the level and nature of diseases (e.g malaria and ebola)

how does soil determine population growth?

-depends on water content, nutrition, soil structure and acidity of the soil

-maintained with chemical fertilisers --> unstable outcomes

how does water supply determine population growth?

needed for hygiene, sanitation, agriculture and drinking

how does geology and other resource distribution determine population growth?

-concentration of other resources--> increase in industrialisation --> densely populated conurbations

- resources depleted -> new tertiary resources

Agricultural productivity

- the ratio of agricultural outputs to agricultural inputs

- measure in terms of yield

Agriculture

the science or practice of farming, including cultivation of the soil for the growing of crops and the rearing of animals to provide food, wool, and other products.

Climate

a region's average weather conditions over a long period

Food security

it exists when all people at all times have access to sufficient, safe, nutritious food to maintain a healthy and active life.

Salinisation

The build up of salts in soil leading to toxic levels for plants. It can occur due to excessive irrigation or poor drainage.

• Dissolved salts rise to the surface with water.

• Evaporation leaves a salt crust, degrading soil.

• Salt-tolerant crops (e.g cotton) may survive.

Soil

the upper layer of earth in which plants grow, consisting of mixture of organic remains, clay and rock particles

Topography

the relief and drainage of an area

Zonal soil

a soil which has experienced the maximum effect of climate and natural vegetation upon the parent rock, assuming there are no extremes of weathering, relief or drainage

The Green Revolution

1940s: wave of technological development started to increase crop productivity -> help developing countries face their growing population's needs

Where di the GR occur?

- Mexico 1944

- saved over 1 billion people from starvation

- Dr Norman Barlaug

What happened in GR?

- new varieties of wheat, rice and maize

- new varieties --> pest infection + required extensive chemical spraying

- large- and medium- scaled farmers in regions (with adequate irrigation facilities, sufficient ability to undertake risks, and good market integration) adopted the new varieties

4 types of farming

- commercial

- subsistence

- intensive

- extensive

Commercial farming

-majority of produce is sold

- income provides a livelihood for the farmers and further investment

subsistence farming

- majority of produce is consumed by farmworkers

- low productivity

Intensive farming

- usually small scale

- capital intesive - high output per hectare due

Extensive farming

- large scale over large area

- low capital and labour input

Total Factor Productivity (TFP)

is the ratio of agricultural outputs to inputs

How does TFP improve in terms of crops?

- higher yielding, disease resistant and drought /flood resistant crops

- efficient and timely cultivation and harvesting practices

- using technologies that indicate precisely when and how much water and fertiliser to apply

How does TFP improve in terms of livestock?

- breeding animals for favourable genetic qualities and behaviour

- using better animal care and disease management practices

- adoption of high quality feeds

What are soils characterised by?

- horizons: distinguishable from the initial material as a result of additions, losses, transfers and transformations of energy and matter.

- the ability to support rooted plants in a natural environment.

What are the horizons?

- O: top layer of soil

- A: topsoil

- B: processing

- C: parent material -> mineral release

- R: bedrock -> solid rock

What are the five functions of soils?

1. Physical stability and support

2. Cyclin nutrients

3. Regulating water

4. Sustaining plant and animal life

5. Filtering and buffering pollutants

What are the two zonal soils?

1. Ferrasol

2. Podsols

Ferrasol

Type of soil found in humid tropical regions along the equatorin S.Hemisphere (e.g Brazil, Central Africa).

• Deep and intensely weathered, low PH (acidic)

• High rainfall leading to nutrients leaching out the soil. Nutrients are constantly cycled between vegetation and topsoil

• Very few nutrients below 50cm depth. Vegetation on surface removes most nutrients

• Material is quickly broken down, darker O and A horizons

• Well drained, less susceptible to soil erosion. Prone to drought due to limited capacity to store water

Uses of Ferrasol

• Shifting cultivation and grazing are common forms of agriculture

• Requires significant inputs of fertilizers and organic matter to maintain fertility (and raise PH)

• Complete removal of vegetation can lead to soil erosion

• Black Pepper and Rubber taping in Brazil

Podsol

• Mature soil, takes between 3000-5000 years to develop

• Found in cool temperate regions of N.Hemisphere, areas with high rainfall and cool temperatures (e.g North Europe, North America)

• Clearly defined horizons are found where precipitation levels are high and temperatures are cool (e.g boreal zone and temperate zone)

• Low in nutrients and very acidic

• Deep ploughing to remove iron hardpan and continuous use of fertilisers are needed to enable crop cultivation

• Nutrients are stored for a long time in the O and A horizon (slow decomposition)

Uses for Podsol

• Used for forestry, recreation or extensive grazing.

• Limited agricultural use due to low fertility, high acidity asnd waterlogging risk (only suitable for acid-tolerant crops)

What are the 4 soil problems?

- soil erosion

- waterlogging

- salination

- structural deterioration

Soil erosion

- the wearing away of the top layer soil.

- it is eroded away by both water

How does repeated erosion reduce the fertility of the soil?

- removal of topsoil

- reduction of the depth of soil available for rooting and water storage for crop growth

- reducing infiltration of water into soil -> increases surface run off

What can eroded fertility of soil lead to?

- loss of seeds, fertiliser and pesticides

- young plants being sandblasted

- increased difficulty of field operations

How can soil erosion damage the environment?

- deposition of sediment onto roads, land and drains

- damage to quality of water courses, lakes and rivers

- increased run-off and sedimentation

- sediment in rivers damage spawning grounds

How to reduce the amount of surface flow of water

- installing and maintaining field drains and ditches. Sediment should be removed from ditches and replaced in the fields where it came from

- reducing the amount of water running off roads and farm track onto fields.

- farmyard manure to stabilise the topsoil

- protecting soil in winter by early sowing or the use of cover crops

- work across slopes whenever possible.

Wind erosion control

- increasing soil cohesion by applying organic matter

- increasing the roughness of the soil surface or by leaving crop residues.

- increasing plant cover -> surface wind speed is cut

- planting lines of trees or hedgerows cuts wind speeds.

Waterlogging

• Water table rises, saturating soil, oxygen in pore spaces becomes insufficient for plant roots to respire.

• This creates an anaerobic environment, roots decompose, leading to crop death

• Breeding ground for mosquitos, transmits diseases such as Malaria, Zika and Dengue.

What conditions does waterlogging occur?

- Surface-fed: Excess precipitation, over-irrigation, or river floodwater exceeds the combination of evapotranspiration and percolation. Gentle relief or basins causing water accumulation

- Groundwater-fed: rate of rising groundwater is not matched by the rate of evapotranspiration.

Salination

the build up of salts in soil, eventually to toxic levels for plants

What causes salination?

- excessive water application. irrigation water contains dissolved salts derived as it passed over and through the land.

- rainwater contains some salts so evaporation of this water leaves lasts behind

How is salination treated?

- flush the soil with lots of water -> flushed water goes to rivers and groundwater..

What does food security depend on?

- availability

- access

- use

- stability

What are the key 5 discussion points in terms of food security?

- there is enough food in the world but not in the places where it is really needed

- future foods can/cannot be met by current levels of production

- national food security is important/ no longer necessary because of global trade

- globalisation may/may not lead to persistence food insecurity and poverty in rural communities

- households get enough food but the distribution within the household or the nutrition fulfilment remains unclear

Knowsley (Overview)

• Part of the Liverpool city region in North-West England. Population of 147,000

• Mix of large industrial estates, housing estates and farmland

• Health is worse than UK average - one of the worst areas in England for premature deaths

• Lower life expectancy - 76.7 yrs for Men (79.4 avg) and 80.8 yrs for Women (83.1 avg)

• Highest cause of death is circulatory and respiratory diseases

Knowsley - Open Space

• Over 60% of Knowsley is green space, important for recreation, physical activity and mental well-being

• Only 10% of residents use outdoor space for exercise and health reasons (17% avg)

• 69% of residents are overweight (65% avg), leading to health issues like heart disease and diabetes

Knowsley - Housing

• In 2011 27% of homes failed to meet the Decent Homes Standard - indicating issues such as leaking roofs, inadequate heating or insufficient insulation.

• This makes houses cold and damp, increasing risk of respiratory diseases.

• In 2011-2013 the rate of premature dearths from respiratory diseases was 58.3 per 100K (33.2 avg)

Knowsley - Air Quality

• Causes by traffic and industry - Two motorways run through the area and has a coal-fired power station nearby

• Air quality is associated with respiratory problems, cardiovascular disease and lung cancer

• Steps such as improving roads to reduce congestion have been taken to reduce air pollution

Knowsley - Unemployment

• Very high unemployment rates - In 2015 7.7% of working-age people were out of work (5.3% avg)

• Unhealthy lifestyles have lead to high unemployment rates - 30% of adults smoke (20% avg) and 24% of deaths are related to smoking (18% avg)

• The council has worked to increase numbers of jobs by encouraging businesses to locate in the Industrial Park. It also aims to improve public transport, making jobs more accessible

Knowsley - Income

• Lower UK average income - £475 per week in 2016 (£539 avg)

• Those living in poorer areas have lower life expectancies than in wealthier areas (more likely to suffer from ill health)

• Low incomes leads to stress and depression - 8.7% (6.5% avg)

• Those with higher incomes are able to access greater range of goods and services (e.g leisure facilities)

• Children in low-income households are more likely to suffer from asthma, obesity and mental health issues

Knowsley - Education

• 25% of people aged 16-64 don’t have any qualifications (15% avg). Students achieve lower GCSE grades

• Education is linked to income and has an impact on lifestyle. People with lower levels of education have a lower life expectency and higher morbidity rates for heart disease, diabetes and asthma

• In 2016 the Education Commissionw as launched to improve education in the area - e.g by attracting outstanding teachers and improving facilities

Semi-arid Climate

• Found near equator between Tropics of Cancer and Capricorn

• Lies between arid hot deserts regions of N/S America, Africa, Southern Asia and Austrailia

• Savanna vegetation, tall grasses and woody trees

• Example is the Sahel - long strip of land beneath the Sahara Desert. Countries include Chad, Mali, Mauritania and Senegal.

Semi-arid climate - Farming

• Unreliable due to climate which can result in food insecurity and malnutrition

• Pastoral (sedentary, nomadic and seasonally nomadic), rainfed mixed and irrigated mixed

• Crops: Millet, cowpea, cotton

• Livestock: Cattle, sheep, goats and camels

Semi-arid climate - Changes over time

• Population growth is outstripping food supply - e.g Niger and Mali have the highest birth rates globally

• Population across the Sahel is likely to triple in next 40 years

• Climate change makes rainfall less reliable resulting in impacts on agriculture

Mediterranean Climate

• Warm coastal region found between 30 and 45° north in latitude.

• Found in countries such as Portugal, Spain, Italy, Greece, Turkey, Algeria and Tunisia

• Small drought resistant crops (shrubs, thorny bushes and small trees).

• Summers are warm to hot and very dry and winters are mild to cool and wet with occasional snow in higher altitudes (50cm of rainfall per year)

Mediterranean Climate - Farming

• Intensive viticulture or grape cultivation support wine, sherry and port industries

• Citrus fruits, olives and figs are cultivate-long roots, sparse foliage and waxy skinned fruit allows them to grow well

• Pastoral farming is uncommon because grass has shallow roots.

• Farming is reliable and has high food security

Mediterranean Climate - Changes over time

• Developments from tourism - pressure on the land

• Climate change is shifting climate belts, warming of just 2°C could lead to arid and semi-arid climate belts developing

• Mediterranean Sea is warming at a faster rate, affecting marine life (sea grass and dolphins)

• Decreasing rainfall during winter means that groundwater aquifers are not recharged and less water for crop growth in summer (need for irrigation)

Malaria

Infectious disease caused by parasites, which are transmitted by mosquitos. Most cases occur in tropical areas (e.g Sub-Saharan Africa).

In 2015 there was more than 200 million cases worldwide - 90% in Africa.

Physical Factors of Malaria

• Mosquitoes thrive in warm climates (e.g. Africa).

• High temperatures speed parasite development.

• Stagnant water (pools, swamps, wetlands) creates breeding grounds.

Socio-economic Factors of Malaria

• Poor education limits prevention knowledge.

• Low income reduces access to treatment or prevention methods (e.g bed nets)

• Poor health reduces the body’s ability to fight infection

• Poor housing increases mosquito entry risk.

• Human activities (e.g irrigation) increase breeding sites.

Effects of Malaria

• Symptoms include Fever, Chills, Nausea and Headaches

• Organ failure, respiratory problems, coma and death can follow in severe cases or if untreated

• Impacts:

  • Lost income from inability to work, financial cost of treatment and hospital visits

  • Children have extended absenses from school, affects education and future jobs

  • Repeated bouts can affect child development

  • Hinders a country’s development

Strategies to manage Malaria

WHO Goals (2030): Reduce incidence/mortality by 90%, eliminate malaria in 35+ countries and prevent it from returning

Most effective strategies:

• Spraying inside walls of buildings with insecticide

• Use insecticide-treated mosquito nets

Other strategies: (mosquitos can gain immunity to insecticides)

• Anti-malarial drugs or vaccines to vulnerable

• Monitoring breeeding so insecticides can be used where needed

• Improving diagnosis and healthcare

Socio-economic impacts of Asthma in China

• Reduced quality of life and missed school/workdays.

• Strain on healthcare systems from hospital admissions.

• Loss of productivity due to work absences.

• High costs of treatment and medication (e.g., inhalers).

• Increased public healthcare spending in affected regions.

Poland to UK Migration

Over 500K people moved from Poland to UK by 2007. 80% were aged 18-34

Pull factors:

• Higher wages (up to 5x Poland’s avg)

• More job opportunities, espeically in construction, hospitality and agriculture

• No restrictions on migration (when UK was in EU)

Push factors:

• High unemployment (19% in 2004)

• Low wages and poor working conditions

• Limited career opportunities

Impacts on UK (Poland migration)

Positive:

• Migrants filled skill gaps and boosted economy

• Contributed to taxes and social security

• Cultural diversity

Negative:

• Strain on public services (healthcare, education)

• Housing pressure, overcrowding

• Migrants more willing to work for lower wages (affecting local workers)

• Differing opinions on immigation

Impacts on Poland (UK migration)

Positive:

• Remittances sent home improved economy ($4b in 2006)

• Reduced unemployment (more jobs available)

• Migrants gained new skills abroad and some returned

Negative:

• Loss of skilled workers, such as doctors, engineers and teachers created labour shortages

• Aging population, most young working-age people moved away

• Social challenges, depopulation in rural areas

Bangladesh (High pop density)

• Population of 173M

• Has a population density of over 1,265 people per km2 (one of the most densely populated countries)

• Populated is concenterated in urban areas like Dhaka (23M residents) and fertile river valleys (e.g Ganges Delta)

• Flat, fertile alluvial plains are ideal for rice farming

• Dhaka and other cities attract migrants due to job opportunities (rural-urban migration)

• Population growth remains high despite falling fertility rate due to improved healthcare

Libya (low pop density)

• Has a population density of only 4 people per km2, one of the least densely populated countries globally

• 90% of population is concentrated around Mediterranean coast where climate is milder and water is more accessible. The interior (Sahara) is largly uninhabited

• Desert takes up 90% of Libya with limited water resources and uninhabitable land

• Oil wealth has lead to urbanisation, with most people living in cities such as Tripoli (empty rural areas)

• Slow population growth due to a low birth rate (2.2 births)

• Political conflict and instability has led to many Libyans to migrate

Bangladesh socio-economic factors

• Life expectancy increased from 46 to 73 due to better quality healthcare, reducing mortality rates and enabling pop growth

• The textile industry has grown, attracting migrants to urban areas

• Despite declining fertility, families tend to have large families, contributing to pop growth

• Around 20% live in poverty, limited access to education and family planning

• High pressure on resources, deforestation and overfishing is an issue

• Dhaka’s infrastructure struggles to keep growth with rapid urbanisation.