The growth of world population
The opulation of an area alters as a consequence of both natural change and migration. The annual population change of an area is the cumulative chnage in the size of a population after both natural change and migration have been taken into account.
In 1999, the world’s population reached 6 billion. It has grown rapidly in the last 200 years particulalry since 1950. Natural increase peaked at 2.2% globally in the 1960s. Since then, falling brith rates have reduced this increase to 1.2%. However, the global population is still expanding by 80 million every year. Estimates suggest that by 2050 the global population will be 9 billion, with zero growth occuring only towards the end of the century.
The growth in the world population has not taken place evenly. The populations of some continents have grown and continue to grwo at faster rates than others, Europe, North America and Australasia have very low growth rates, In 1995, their share of the world’s population was 20%. This is expected to fall to 12% by 2050. It is estimated that Europe’s population will shrink to 90 million during this period.
Asia has a rapid, but declining, rate of population growth. Between 1995 and 2050, China, India and Pakistan will contribute most to world population growth. Indeed, it is estimated that by 2050 India will overtake China as the world’s most populous country. Another potential area for growth is sub-Saharan Africa, particulalry Nigeri and the Democratic Republic of Congo.
Graph of global population growth
Picture
Causes of population growth
Several different factors interrelate to cause the growth in the world’s population:
· Health –the control of disease, birth control measures, infant mortality rates, diet and malnutrition, the numbers of doctors and nurses, sexual health, sanitation
· Education– health education, the age at which compulsory schooling finishes, females in education, levels of tertiary education and literacy levels
· Social provision – levels of care for the elderly, availability of radio and other forms of media, clean water supply
· Cultural factors – religious attitudes to birth control, status gain from having children, the role of women in society, sexual morality
· Political factors – taxation to support services, strength of the economy, impact of war and conflicts, access to healthcare and contraception
· Environmental factors – frequency of hazards, environmental conditions that breed disease
Other bits and bobs
Birth rate, death rate and natural change
Birth rate: the number of babies born per 1,000 people per year. Can be as high as 50 per 1000 per year but the availability of birth control means that such high birth rates are now rare.
Death rate: the number of deaths per 1,000 people. Normally death rates lie between 5 per 1,000 per year and 20 per 1,000 per year. This can increase significantly if there is an epidemic, famine or war.
Two factors affect the level of the death rate:
· health care has improved in poorer countries, lowering death rate
· having so many people under the age of 15 reduces the chance of death
Natural change: this is the difference between birth and death rates in a country. It is a useful measure of a population’s growth or decline.
Natural increase: this is when the birth rate exceeds the death rate. This has been the case recently except in periods of famine, war or epidemic. Some countries have reduced their birth rates and this has led to a natural decrease where the death rate exceeds the birth rate.
Life expectancy: the number of years a person is expected to live, usually taken from birth.