Hello. I'm Rebecca Kippen. Welcome to these three lectures on population ageing. In these lectures we'll explore definitions of population ageing and the reasons populations are getting older. We'll then look at some data sources on population ageing and global trends over the 20th century through to the present. Finally, we'll consider possible population ageing trends in the future. Will life expectancies continue to increase and populations continue to age? Or will people lead shorter lives in the future? Due to, for example, rising levels of obesity and diabetes. Each one of us individually is getting older, one year at a time. One calendar year in time means one year older in age. However, when we are measured together as a population, populations can either become older, get younger or stay the same age. When we talk about populations becoming older or population ageing, this is measured by the proportion or the percentage of population of older ages. Generally, the older age population is defined as those 65 years and over. So population ageing is measured by the percentage of the population age at those ages 65 and above. Populations around the world are getting older. That is, the proportion of populations age 65 years and above is becoming larger. This is projected to continue over the 21st century, and is now considered one of the great policy challenges of the current century. Why is this considered a policy challenge? It's a wonderful thing that globally people are living longer. However, in general, older populations mean higher health care costs, aged-care costs, and pension costs, at the same time that fewer people are in the paid labor force because the larger older age population are mostly retired. These challenges are being addressed by governments around the world and will be discussed in more detail in future lectures in this series on the economics of ageing. So why are populations getting older? With an increase in the proportion of populations age 65 years and over. The first reason is the birth rates around the world have been falling. Falling birthrates mean fewer births. Which mean fewer young people and therefore proportionally more people at older ages. The second reason is the obvious one. People are living longer lives than in the past. And they're therefore much more likely to survive well into old age. The third reason is past demographic shifts. For example, many countries experienced a baby boom after the Second World War. Lots of births from 1945 when the war ended means lots of people shifting into old age 65 years later, from 2010 in this case. Let's look at these three factors in action using Australia as a case study. This chart shows Australia's total fertility rate from the beginning of the Twentieth Century through to the present day. Here fertility refers to the numbers of babies that women give birth to, not the general meaning that we know of that it's the ability to conceive and bear children. The total fertility rate is a measure of the average number of children born to each woman over her lifetime. You can see that in 1901, the total fertility rate was just over 3.4 births per woman. This fell through the 1910s, 1920s, and early 1930s. Bottoming out at around 2.1 in 1934. We then see an increase through the remainder of the 1930s, the 1940s, and 50s. Fertility peaked in 1961, at 3.6 births per woman. Then fell dramatically over the next two decades. Since 1980 the total fertility rate has been roughly stable at around 1.8 to 1.9 births per woman. So from this we would expect to see two affects on population ageing in Australia. The first is that caused by relatively low fertility over the past three decades. Fewer births means fewer young people means proportionately more people at older ages. The second is the baby boom that occurred over Australia in the 1940s and 50s. These past high birth rates mean there are a lot of people shifting into old age now, which increases population ageing. The other reasons populations are ageing is because of increasing life expectancies. This chart shows average life expectancy for males and females for Australia from 1901 to 2012. You can see there's been an enormous increase over that time. Male life expectancy has increased from 52 years to 80 years, while female life expectancy rose from 56 to 85. Almost 30 years increase for each sex. The increase has been fairly steady except for a dip in 1919 due to the influenza pandemic, and a brief levelling off during the 1960s. The three factors discussed here, falling birthrates, increased longevity, and past demographic shifts have resulted in the ageing of Australian's population. We can see that here, in Australia's population pyramids in 1901, 1961, and 2013. A population pyramid is a graphical representation of a population by age and sex. Males are on the left and females on the right. Remember females are always right. And each band represents a five year age group, starting with age zero to four years at the base. Then five to nine, ten to fourteen, and so on. Finishing with age 100 years and over at the top. The population pyramid for Australia, in 1901, almost has that traditional pyramid shape. With a broad base tapering gradually to the top. This is the classic shape that results from high birth rates and high death rates. High fertility means lots of babies and young children in the population. But high death rates mean people die off fairly quickly as they progress up the pyramid. Looking at the 1961 pyramid, we can see the effect at the base of the post-war baby boom. Fifteen years at that time of high fertility meant a large population at age zero to fifteen. There are also proportionately more people at the older ages due to the longer lives that people were living at that time. In the final pyramid, for 2013, we can see the effect of all three factors, recent low birth rates, higher life expectancies, and the past baby boom. There are proportionately fewer people at the younger ages, due to the low birth rates. And proportionately more people at the older ages. In fact, the proportion of the population age 65 years and over, has increased from 4% in 1901 to 9% in 1961, and 14% in 2013. Australia's population is ageing, as are those of most other countries around the world. At this time, I'd like you to consider. Do you think it's useful to have a specified age above which people are considered old? If yes, what should this age be? Should it differ between populations or change over time? Finally, we finish off with some population ageing definitions. Generally the old or aged population means the population age 65 years and over, or sometimes the population age 60 years and over. The oldest, old population refers to the population aged 85 and above, or in some cases 80 and over. Centenarians are those aged 100 and above and super-centenarians are the very small group at the moment aged 110 years and over. Numerical ageing means an increase in the numbers of people at older ages. While structural ageing refers to an increase in the proportion of people at older ages. Thank you for your time today and see you soon in the second lecture on population ageing, where we will discuss sources of data and trends and patterns of population ageing around the world.
