TOO CROWDED FOR COmFORT?
On 12 October last year, somewhere in the world, a baby was born. Nothing very remarkable about that – one is born every 3 seconds. But this child had the distinction of bringing the world’s population to 6 billion. That’s 6 thousand million people alive on the planet at this moment.
Rapid population growth
It is only 13 years since the 5 billionth baby was born, in 1987. Yet it took all of human history until around 1650 to reach the first billion, 200 years to reach the second, 70 years to reach the third, and 44 years to reach the fourth. The human population is growing at an ever-increasing rate.
Before you start imaging a future world where you and your grandchildren only have room to stand elbow to elbow, be reassured that demographers (people who study populations) expect the world’s population to level off some time this century. Indeed the rate of increase is already slightly less rapid than it was in the 1980s. The latest estimates predict a world population levelling out somewhere between 9 and 12 billion by about 2070. That is still almost double today’s global population!
The demographic transition
A model called ‘the demographic transition’ helps explain why countries go through a surge of population growth as they develop economically, before levelling off.
Stage1: For much of human history, people had large families. This was partly owing to a lack of contraception, and partly because infant mortality was high – people had additional children as ‘insurance’ that some, at least, would survive to become adults.
Despite these large families, populations grew slowly because life expectancy was so short, particularly amongst poorer people. Poor sanitation and crowded living conditions meant that disease was easily transmitted; people had little resistance to illness because of poor diet; and lack of medical knowledge meant that treatment was often very hit and miss. The result was a high death rate, cancelling out the large number of births.
Stage 2: As countries developed economically there were immediate improvements which meant that people were less likely to die at a young age. In the growing cities of Europe and North America at the start of the twenties century underground sewers and piped water, flush toilets and the increasing use of vaccinations all meant that disease was less likely to be generated and spread. Better diets helped people resist infection, and advances in medicine led to more effective treatment of disease.
Birth rates had more to do with social attitudes, and these take longer to alter. There was widespread controversy about the use of birth control, the role of women in middle-class homes as home-makers and childrearers, and a continuing sense of large families being ‘the norm’. As a result the birth rate remained high, particularly in rural areas, where there was still a real threat of children dying in infancy, and where they were needed on the farm to look after animals, do chores and help bring in the harvest. The consequence was a huge increase in population as births far out weighed deaths each year.
Many LEDCs (less economically developed countries) are passing through this stage now. This explains why global population is still growing rapidly, even though the MEDCs (more economically developed countries) have moved on to stages 3 and 4.
Satge 3: As social attitudes slowly changed, parents began to limit the number of children they had, and the rate of increase of the birth rate started to slow. In MEDCs the second half of the twentieth century saw family sizes reduce from an average of 3.5 to 2.1 children per family. A number of factors were involved: the widespread availability of family-planning methods, the fact that young people are required to attend school until their mid- to late teens and remain a financial burden often into their mid-twenties, and the desire for a more affluent lifestyle, which is restricted by having a lot of children. The rate of population growth in MEDCs started to reduce during the last 50 years even though the total population in those countries was still increasing.
Stage 4: Modern medical techniques have reduced the annual death rate in many MEDCs to less than 10 per 1000, and the birth rate has fallen to similar levels. When the two are in balance, the population stops growing and levels off. This is often a phase of population stability.
Stage 5: Some demographers believe that there is a fifth stage to the model, in which the birth rate and a population goes into decline. It is noticeable that in countries such as Italy – which has one of the lowest fertility rates in Europe at 1.8 births per 1000 women of child-bearing age – not enough babies are being born to maintain the population level as people die.
Social attitudes have changed significantly in the last 20 years. Many women want to follow a carrer rather than devoting their time to raising children. Lifestyle choices also mean that having children may get in the way of the desired quality of life. As a result birth rates are continuing to fall in many European countries. It is not clear whether this is a temporary feature, as women choose merely to delay having children until they are into their thirties or forties, or whether it is a permanent trend, with people choosing not to have children at all.
The stages of transition described above pose population issues for countries around the world. This might mean planning for the anticipated explosion of population in LEDCs as they pass from stage 2 to stage 3 – Kenya currently has over half its population under the age of 18 and an average family of six children. Alternatively it might mean coping with an ‘ageing’ population in Japan, Canada and the UK as these countires enter a phase of population stability in stage 4. Countries such as Italy and Belgium in stage 5 may feel a need for action to reverse the current trend of a decline in population.
We can expect that, as more countries reach the later stages of demographic transition, the world’s total population will level off some time this century. What is uncertain is quite what number, and quite what date.
Answer the questions:
What stage of transition is your country on?
Is it possible to control the population growth?