Demographic Transition Model
The demographic transition model shows population change over time. It studies how birth rate and death rate affect the total population of a country.
The five stages of the demographic transition model
- Total population is low but it is balanced due to high birth rates and high death rates.
- Total population rises as death rates fall due to improvements in health care and sanitation. Birth rates remain high.
- Total population is still rising rapidly. The gap between birth and death rates narrows due to the availability of contraception and fewer children being needed to work - due to the mechanisation of farming. The natural increaseis high.
- Total population is high, but it is balanced by a low birth rate and a low death rate. Birth control is widely available and there is a desire for smaller families.
- Total population is high but going into decline due to an ageing population. There is a continued desire for smaller families, with people opting to have children later in life.
As a country passes through the demographic transition model, the total population rises. Most LEDCs are at stage 2 or 3 (with a growing population and a high natural increase). Most MEDCs are now at stage 4 of the model and some such as Germany have entered stage 5. As populations move through the stages of the model, the gap between birth rate and death rate first widens, then narrows. In stage 1 the two rates are balanced. In stage 2 they diverge, as the death rate falls relative to the birth rate. In stage 3 theyconverge again, as the birth rate falls relative to the death rate. Finally in stage 4 the death and birth rates are balanced again but at a much lower level.
One Child Policy
The birth rate in China has fallen since 1979, and the rate of population growth is now 0.7 per cent.
There have been negative impacts too - due to a traditional preference for boys, large numbers of female babies have ended up homeless or in orphanages, and in some cases killed. In 2000, it was reported that 90 per cent of foetuses aborted in China were female.
As a result, the gender balance of the Chinese population has become distorted. Today it is thought that men outnumber women by more than 60 million.
Long Term Implications
China's one-child policy has been somewhat relaxed in recent years. Couples can now apply to have a second child if their first child is a girl, or if both parents are themselves only-children.
While China's population is now rising more slowly, it still has a very large total population (1.3 billion in 2008) and China faces new problems.
Mexico USA Migration
There is a 2000 km border between the USA and Mexico as illegal migration is a huge problem. U.S. Border Patrol guards the border and trys to prevent illegal immigrants from entering the country. Illegal migration costs the USA millions of dollars for border patrols and prisons.
In 2012, the Obama administration deported a record 409,849 undocumented immigrants, arriving at a rate of about 34,000 a month.
Many Americans believe that Mexican immigrants are a drain on the economy. They believe that migrant workers keep wages low which affects Americans. However other people believe that Mexican migrants benefit the economy by working for low wages.
Mexican culture has also enriched the USA border states with food, language and music.
Impacts on Mexico
The Mexican countryside has a shortage of economically active people. Many men emigrate leaving a majority of women who have trouble finding life partners. Young people tend to migrate, leaving the old and the very young.
Legal and illegal immigrants together send some $6 billion a year back to Mexico. Certain villages such as Santa Ines have lost two thirds of their inhabitants.
There is a large wage gap between the USA and Mexico. Wages remain significantly higher in the USA for a large portion of the population. This attracts many Mexicans to the USA.
Many people find living in rural Mexico a struggle because they have to survive with very little money. Farmland is often overworked and farms are small.
It is estimated that 10,000 people try to smuggle themselves over the border every week. One in three get caught and those that do are likely to continue trying to cross the border at least twice a year.