Population density and distribution http://www.flickr.com/photos/arenamontanus/375127836/
2.1 Population distribution and density at global and local scales
• Factors influencing population distributions
Appreciate the broad, global distribution of population
analyse the distribution in more detail at a
Describe and quantify the spatial variations in a chosen country
Explain the variations in terms of environmental, economic, historical, cultural and political factors.
www.maps.com/ref_map.aspx?pid =12880 75% people live within 1000 km of sea 85% live in areas less than 500m high 85% live between latitudes 68 o North and 20 o North <10% live in S. hemisphere
There are over 6 billion people in the world today. Distribution is very uneven – there are a number of different reasons for this (more on these reasons later!) Asia and Europe have the highest densities of population. World’s population varies latitudinally – 80% lives between 20 and 60 degrees north of the equator. Primary concentrations >100 per sq km - SE Asia, Europe + NE USA. Secondary concentrations 25-100 per sq km – California, coastal Brazil, Nile Valley. Areas of low population density 2-25 per sq km – Norway, New Zealand, Canada, North Africa, S Argentina, Australia. 64% of the world’s land area has <2 people per sq km. 35-40 of this land area is regarded as unihabitable. Areas with environmental advantages tend to be densely populated while those with disadvantages tend to be sparsely populated with social and economic deficiencies. There are exceptions to this - eg Bangladesh.
Population density = number of people per sq km.
Usually shown by a choropleth map
Densities are grouped into classes and coloured lighter or darker to show lesser or greater density,
Maps are easy to read but:
suggest abrupt changes at country boundaries
Key to explaining distribution is the ability to feed a population. The world’s 6 billion people are not distributed evenly across the Earth’s surface. Almost all of the world’s inhabitants live on 10% of the land area 75% live within 1000 km of the sea 90% lives north of the equator where the larges proportion of the total land mass is located (63%) 85% lie in areas < 500m high 85% live between latitudes 68o N and 20o N < 10% live in the southern hemisphere. Most live in temperate low lying areas with fertile soils
pg 122 How will the World’s population be distributed in the future? By 2030 the population of E and S Asia will be over 4.1 billion people, about 1.8 billion more than now. They will comprise 44% of the world’s population on 13% land area Areas of the Earth that are not presently inhabited will remain uninhabited Within the inhabited areas there will be a core – periphery polarisation Rapid urban pop growth will continue in LEDCs
Describe the differences between population density and population distribution .
Describe the world pattern of population distribution.
Economic Political Cultural Historical Resources Climate Physical How would this contribute to a densely populated area (egs) How would this contribute to a sparsely populated area (egs) Factor
Homework question…. Explain why the distribution of the world is uneven.
Describe and quantify the spatial variations in a chosen country and explain the variations in terms of environmental, economic, historical, cultural and political factors
See Waugh pg 347
Over 90% of Brazilians live in a discontinuous strip about 500km wide adjacent to the east coast
This accounts for <25% of the country’s total land area
Density declines rapidly towards NW
NE – dry, long and frequent drought, high temps and poor soils make th area unsuitable for growing high yield crops or rearing animals
Sertao also lacks known mineral or energy reserves, communications are poor and basic services of health, education, clean water and electricity are lacking. Birth rates are high
There is a rapid migration to urban areas, high infant mortality rate and short life expectancy
Tropical rainforest climate is hot, wet and humid, rivers flood annually and there is a high incidence of disease
Forest is difficult to clear, soils are rapidly leached and become infertile.
Communications are difficult to build and maintain
Area has suffered from lack of investment. Supports subsistence economies.
Two anomalies – Manaus. Had two growth periods:
Rubber boom at the turn of the 19 th 20 th centuries while the second began in the 1980’s with the development of tourism and the granting of its new status as a freeport.
Carajas and Trombetas – mineral exploitation
Tucuri – hydro-electricity
Moderately populated areas
Easterly parts of the Brazilian Plateau. Climate is cooler and it is healthier than on the coast and rainforest
Soil is a rich terra rossa ideal for growing coffee.
Several mineral resources have been found
Rainfall is irregular with a long winter drought
Communications are still limited
Federal investment has been insufficient to stimulate much population growth
Highest population densities
Eastern parts of the plateau around Sao Paulo and Belo Horizonte and east coast have the highest population densities
Coastal area is often hot and humid
Water supply is good
Several natural harbours proved ideal for ports – trade and industry
Salvador, first capital was centre of slave trade
Rio became second capital developing as an economic, cultural and administrative centre. It has received increasing numbers of tourists from overseas and migrants from the north of Brazil
Sao Paulo is one of the fastest growing cities in the world
Cooler climate and terra rossa soils led to growth of commercial coffee farmiing
Access to minerals such as iron ore and energy supplies made it an industrial centre
It has received high levels of investment leading to development of communications network and modern services.
New growth poles
Around Belem, based on discovery and exploitation of vast deposits of iron ore and bauxite, construction of HEP and the advantage of access along the coastal strip and Amazon corridor
Brasilia, built in the early 1960’s to try to redress the imbalance in population density and wealth between the south east of the country and the interior.
Describe the global distribution of population. You should include these terms in your answer: sparsely populated, densely populated Using only an annotated map, explain how physical, historical, cultural and political factors have affected the distribution of a country of your choice. Political Economic Cultural Historical Resources Climate Physical How would this cause a sparsely populated area (examples) How would this cause a sparsely populated area (examples) Factor