Population and the environment:

Countries with the largest populations:

• China

• India

• USA

• Nigeria

• Indonesia

Why does India and China have large populations?

• Had large populations 100s of yrs ago

• Large land mass = allowed farming and animal grazing, fertile land - food availability, able to house many people.

• Had river valleys = alluvial soils created

• Near equator so year round production of crops - hot temperatures (tropical monsoon climate = wet and hot.

• India was one of the first countries that had domestication of animals

What Aspects of physical environment affect population?

• If there is a good water supply in the area = rivers, lakes, oceans. Allows farming, fishing and trade to occur.

• Temperature = near the equator, cold environments can lead to less people, hot climates causes population to increase.

• Soil fertility = geology of the local area can affect soil fertility.

• Drainage/water supply

• Topography = shape/height of the land (relief)

What affects the populations of countries:

• Climate

• Soil fertility

• Water supply

• Geology

Climate:

• Rainfall

• Wind velocity

• Solar insolation (amount of sun an area gets)

• Temperature = many crops need temp of atleast 5*C, pasture-fed cattle must be provided with extra food <5*c

• Characteristics of climate can also affect he incidence of disease such as malaria, yellow fever and ebola.

Soil fertility:

• Depends on soil structure, texture, acidity(pH), organic matter and nutrients.

• Influences the type of farming system and in turn farming influences soil health.

• Chemical fertilisers and pesticides may be added to improve it = NPK, Monoculture, rotational cropping.

• Some fertile areas may be prone to hazards (eg volcanic eruptions and floods)

• Topography (relief of the land) may also affect soil depth - shallower on steep slopes, can be managed with contour ploughing.

Water supply:

• Main use is for irrigation = agriculture accounts for 69% of global water use and most of this is for irrigation.

• Also used for human hydration, hygiene, sanitation(sewerage) and industrial processes.

• Eg = 95% of Egypt’s population of 80 million live within 12 miles of the Nile.

Geology:

• Concentration of resources (such as fossil fuels) have given rise to industrialisation and consequently densely populated areas Eg in Europe (Germany’s Ruhr valley), USA, India, and China.

• Even when resources become depleted (they run out), large, dense populations remain with new tertiary industries to serve them.

Factors Affecting Population Changes:

• Migration = rural to urban migration. urban to rural migration (counter urbanisation)

• Natural increase = births > death (in cities) - demographic makeup.

• Improving healthcare = Life expectancy increases, reducing deaths and infant/child morality rate decreases.

Global pattern of population density:

• population density is unevenly distributed across the globe, with high density in specific continents and regions.

• south/east asia = largest zone of extreme populaton density, with most countries exceeding 200 - 500 people/km².

• western/central europe = also major high density region (mostly 200 - 500 people/km²)

• north africa = extreme contrasts, coastal and riverine zone with high density whereas inland Sahara region is sparsely populated.

• central and northern asia and northern north america = represent the largest low density region globally.

Population growth rates around the world:

• Highest growth rate = (2% - 5%) = Sub-Saharan Africa (Niger, DRC, Chad, Angola, ME and Central Asia)

• Moderate growth rate = (0.5% - 1%) = North America (USA, Canada), parts of South America (Bolivia, Ecuador), Oceania (Australia) and parts of Southeast Asia.

• Slow growth rate = (0% - 0.5%) = large parts of China/ East Asia, South America (Brazil, Argentina) and select nations in Northern/Western Europe.

• Negative growth = Eastern and Southern Europe (Ukraine, Greece, Bulgaria). Russia and Japan as well (aging populations and falling fertility rates below replacement level)

Population trend of the world:

• Total world population reached 8 billion in 2022 and is projected to peak at over 10 billion in 2061 before slowly declining after 2100.

Annual Growth rate decline:

• The global annual growth rate, which peaked at 2.2% in 1964 and dropped to 0.9% in 2023, to continue falling until it reaches a negative growth rate of -0.1% by 2100.

Annual Growth rate of continents:

• Africa = projected to experience the most rapid and dramatic expansion significantly increasing it’s share of the total world population by 2100.

• Asia = Expected to maintain the largest population share initially (2050) before a steady decline through 2100.

• Europe = Projected to undergo continuous, gradual population contraction through 2100.

• North/South America and Oceania = Supposed to remain stable with minor growth around 2050 followed by slight decline or stagnation (Oceania remaining very small in total proportion).