How and why has global population changed?

Global population has increased rapidly since 1950 due to the baby booms after differant wars.  Global population dropped after wars.  Another reason population has dropped has been due to the one child policy,  the policy in which countries with a large population try to reduce the population by rewarding people who only have one child.  They usually reward their child with free education.  If people dont stick to the law then they can be punished, they could be forced to abort their child.  But another reason population increased was due to the baby bonus system which was introduced mainly in Italy.

The demographic transition model shows what stage a country is in.  There are five stages in the DTM.  The first stage is High Stationary this stage is for countries with a small population and high death rates.  The next stage is Early Expanding, this stage is for countries that have a high birth rate and a death rate which is falling rapidly this could be due to advances and more availability of health care.  The next three stages are for countries with have a low/falling death rate and birth rate.  Three examples of countries in these stages are;  Brazil, Germany and France.     

Somalia is a developing country, it has a very young population.  And life expectancy is low,  it has a very small population and very high birth rates.  Somalia could have such high birth rates because of contraception being less available in the country.

Italy is a developed country with a low birth rate as contraception is widely available.  And due to the baby boom after the secound world war.  Italy has an ageing population and a high life expectancy.  Italy has a high poulation.  The ageing population means that less income and resources are availble to the country.  To improve the situation Italy have introduced a pro-natalist policy which awards people for havng children.  To improve the problem.  

Some countries manage their populations because they are either too big or too small.  Or their population could be too youthfull or the country could have an ageing population.  This is a massive concern for some countries as their are not enough people to work to support the elderly.  And the populartion can become unbalenced.  China is an example of a country which manages its population.  China has a anti-natalist policy in place,  this works by limiting people to having one child per family.  This is called the one child policy.  It works by benefiting people for having one child by offering free education to the child.  The advantages of the policy are that it quickly reduces  birth rates and makes the population more balenced.  However some disadvantages are that it forces people to abort and people have no choice into the ammount of children they have.  This is not fair in my point of view.  

Push factors - A push factor is something that pushes people out of a country. e.g. War. 

Pull factors - A pull factor is something that motivates someone to go to a country. e.g. Climate

Ageing population - A population which has a large number of elderly people. e.g. Italy

Youthfull population - A population which has a large number of young people. e.g. Somalia

High BR - High number of children being born. 

Low BR - Low number of children being born.      

Population can be affected by push and pull factors.  push factors can mean an increase in population in an area because people are attracted to some of the features of an area. e.g Better standard of living.  Population can also decrease in an area because of push factors, Push factors can push people out of an area because of things like war. 

Some countries have an open door policy, this means that they allow people in and out of a country freely.  Some countries have a points based system, this means that people can only enter a country if they have a certain skill. Some advantages of the points based system compared to the open door policy are; that people bring skills to the country and reduces the ammount of people immigrating to the country.  Some advantages of the open door policy compared to the points based policy are; that it offers people support and it can help the countries population issues.   

There are two differant types of migration, these are forced and economic migration.  Forced migration is when people have no choice put to leave a country.  And economic migration is when    people move from a country because of economic reasons.

Migration can affect host countries because as people leave the population decreases.  This can mean that less economically active people are in the host country meaning that less resources are available and there is no money to pay the elderly.  Migration can also affect origin countries because it cn mean that they can become overpopulated and overcrowded, which can cause big problems for the country.