According to Encyclopedia Britannica, fertility rate is the average number of children born to
women during their reproductive years. The single most important factor in population
growth is the total fertility rate (TFR). If, on average, women give birth to 2.1 children
and these children survive to the age of 15, any given woman will have replaced herself
and her partner upon death. A TFR of 2.1 is known as the replacement rate. The reason that it’s 2.1
and not 2 is that the extra 0.1 accounts for higher probability of males born, and mortality
prior to the end of a person’s fertile life. A rate greater than 2.1 will generally result in
population growth, whereas a rate less than 2.1 will eventually result in population decline.
Here is a map of global fertility rates as of 2020. Anywhere in dark green or any shade of blue
is below replacement levels. These include most nations in Europe, Canada, Australia,
Brazil, Russia, China, the United States, and many others. The lowest levels of fertility
are found in developed parts of East and Southeast Asia: Singapore,
Hong Kong and South Korea, with South Korea having the lowest fertility rate in the world
at 0.84. That’s less than one child on average per woman. Countries shaded in yellow, red, and purple
have higher than replacement-level fertility, with Niger having the highest rate at 7.0.
Higher fertility rates in developing countries reflect the need for children to engage in farming
and other economic pursuits as well as the lack of contraceptive access.
According to OECD data, fertility rates have been falling significantly over the last few decades
with most developed countries now below replacement levels. People in developed
countries are simply not having enough children to replace their populations.
There are many reasons for this, but it is largely due to women’s changing roles,
employment shifts, and advances in reproductive health. In Korea for example,
more women are pursuing wealth and a higher standard of living rather than raising children.
Both Japan and Korea now have declining populations. As the older generations start
to die off, the younger generations are simply not having enough children to replace them.
This has resulted in rapidly ageing populations.
According to the Australian Bureau of Statistics latest release on
births in Australia, we have a total fertility rate of 1.58, well below replacement level. For
Aboriginal and Torres Strait Islander women, the fertility rate is significantly higher at 2.25,
which would ultimately result in population growth in the Aboriginal and Torres Strait Islander
community if maintained. We can see in this graph that the fertility rate has dramatically
fallen in Australia since the 1960s. Actually, it’s been below replacement levels since 1976!
Since 2010, the fertility rate has really started to fall, from 1.95 in 2010 to 1.58 in 2020.
Australian women are turning away from motherhood, or at least, turning away from large families.
Despite this massive decline in fertility rate, why isn’t Australia’s population in decline?
Actually, it’s been significantly growing. One reason is population momentum. According
to Population Education, one of the most common misconceptions about population growth is that
a population stops growing once replacement level fertility is reached (a roughly 2-child average).
In fact, due to population momentum, a country’s population can continue growing for another 70
years once replacement level fertility is reached. Here’s an example from Wikipedia. Assume that a
population has three generations: Gen 1 (the oldest), Gen 2 (those of child bearing age),
and Gen 3 (the children). Further assume that this population has a fertility rate equal to
four. That is, each generation is twice the size of the previous. If the population of the
first generation is arbitrarily set at 100, the second is then 200, and the third is 400. That
gives us a total initial population of 700 (100 + 200 + 400). Now assume that at the end of the
third generation, fertility falls to replacement (for simplicity, let’s assume that to be two).
Now take the population forward in time to the next generation. The first generation dies,
and the new generation, Gen 4, is equal to the third (because now fertility is at replacement).
We can repeat the process again to reach the fifth generation. The fifth generation
is again equal to the fourth and now the population’s three generations are equal,
and the population has reached equilibrium. The initial population has grown from 700 to 1,200
even though fertility dropped from four to two at the end of the third generation.
Population momentum carried the population to higher levels over the next two generations.
So what’s another reason why the population of Australia is still growing?
I think many of us would already have guessed by now, immigration! According to the ABS’s latest
release on Migration, for the year ending 30 June 2020, there were over 7.6 million
migrants living in Australia. Almost 30% of Australia's population were born overseas.
Australia is certainly an immigration nation. As we can see in this graph, in the last
decade or so, Australia’s net migration has been hovering around the 200-250,0000 mark.
People want to move to Australia. Of course, there has been much public debate about Australia’s
immigration rate. There’s concerns around the environment, housing and infrastructure,
employment, and social cohesion just to name a few. Some people want more immigration,
some people want less. Generally speaking, the government want more. Why? It’s the economy,
stupid! Sustained low fertility rates may signify a rapidly ageing population, which
may place an undue burden on the economy through increasing health care and social security costs.
“Australia needs ‘explosive’ surge of 2 million migrants. Australia needs an explosive post-World
War II-style immigration surge that could bring in 2 million people over five years to
rebuild the economy and address worsening labour shortages, according to NSW government advice”.
“Opening Australia’s border is ‘better for us all’, RBA Governor Philip Lowe says”. And here’s
some older stuff for you. “In 2010, both major parties continued to support high immigration,
with former Prime Minister Kevin Rudd advocating a 'Big Australia'; and Opposition Leader Tony Abbott
stating in a 2010 Australia Day speech that: "My instinct is to extend to as many people
as possible the freedom and benefits of life in Australia"”. “On 7 August 2018, the Australian
Bureau of Statistics population clock reached 25 million 33 years ahead of predictions,
with 62% of the growth in the last ten years being a result of immigration”. However,
“In 2019, a Lowy Institute poll found that 49% of Australians say that ‘the total number of migrants
coming to Australia each year is too high’, while a minority said it is ‘too low’ (13%),
representing a 10-point rise in opposition to immigration since 2014”.
But basically, because there are economic benefits, and because there is a real risk
of a shortage of working-age people to support an ageing population, governments will almost always
push for an increase in population. And if the locals aren’t having enough babies, the government
will import the people instead. What do you think? Do we need population growth at all costs?