Population growth

Population growth is the change in population over time for a particular place.  We tend to look at human countries within countries, whose governments then attempt to manage that change.  However, in today’s globalised world we must also consider Global patterns in population change.  Over the years population has changed dramatically. In 1540 the population stood at 300 million. In 1750 the population was estimated at 791 million. In 1900 it had again grown to 1.7 billion. By 1950 it had reached 2.5 billion. More than a 50 % increase in the last 50 years. Between 1950 and 2000 the population grew to 6.2 billion. It is predicted in the next 50 years it will double again to almost 12 .5 billion. Problems which arise due to the rapid increase of population are that of over- crowding, resulting in shortages of food and water, not enough health care and fewer means of Education. It also decreases our natural habitat because we destroy woodlands, rain forests, forests and areas of natural beauty; as we need the space to build houses, schools and Health Centres. This is the concept of OVER POPULATION.

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This is change in population is known as the J curve graph because of its shape.  It is thought that the curve will become an S shape as population growth slows down. This growth is said to be EXPONENTIAL because it continually increases over time.  It is predicted that growth will slow down in the future.  This issue ties in with the relationship between population and resources, will resource exploitation and development be sustainable and be able to keep up with population growth.  In the future, there are several scenarios that could play out, from continued extreme exponential growth, to stabilisation and then possible global population decline. In 2007 the United Nations Population Division projected that the world's population will likely exceed 10 billion in 2055. In the future, world population has been expected to reach a peak of growth, from there it will decline due to economic reasons, health concerns, land exhaustion and environmental hazards. According to one report, it is very likely that the world's population will stop growing before the end of the 21st century.

The most recent milestone came in 2012, the day of 7 billion people, and for the near future global population growth shows no sign of slowing down.  The population has grown by 1 billion in just 12 years - find out more on the BBC

Indeed, the time taken to add a billion people has also reduced.  As shown in the table below, the years are the closest approximates (source)

Most of the population growth is found in LEDCs (Less Economically Developed Countries) such as China and India. Indeed, these 2 countries alone account for 36% of World population in 2012 whilst 60.3% of the World’s population can be found in Asia and only 10.6% in Europe! Africa’s population growth is large despite the Aids virus lowering life expectancy.

There are also clear Geographic patterns as revealed by the map below;

• Sub Saharan Africa and many of the World’s LDCs have very rapid growth rates
• MEDCs such as those countries in Western Europe and North America have slow population growth rates
• Many LEDCs and NICs in Asia and South America have reasonable growth rates but those are falling in many NICs such as India and Brazil
• There are places such as Eastern Europe, Japan and South Africa where we have population decline.

NATURAL INCREASE, BIRTH AND DEATH RATES

Birth Rate is the term used to define the number of babies born every year per 1000 people in a population.

Death Rate is the term used to define the number of deaths every year per 1000 people in a population.

Natural increase in a population occurs where Birth rate is greater than death rate. That is, that there are more births than deaths in that population in a year.

Natural decrease occurs when death rate is greater than birth rate. This means that more deaths occur in a population than babies are born so population numbers decline.

How is the natural increase found?
 Natural Increase (per cent) =    Birth rate - death rate
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LEDC'S are more likely to have a higher death rate than MEDC'S due to illnesses and lack of medical treatment.  The natural increase is given as a percentage, but we must be cautious.  Even % growth that appear small at say perhaps 2% can yield HUGE changes in population size.  This is also not to be confused with replacement birth rate, which is 2.1 babies per woman.

Of course, this balance is changed by Migration. If people move Into a country (Immigrants) the population will increase. If people leave or Exit a country (Emigrate) the population could decrease.