Ten years ago, experts didn't think the world's population would peak this century but in a "significant" turnaround, this scenario is now considered highly likely.
The United Nations has today released its most recent analysis of world population, which now estimates there will be 700 million fewer people in 2100, 6 per cent less than anticipated a decade ago.
"Five years ago, we were talking about a very different population future for the world," Demographer Dr Liz Allen of the Australian National University (ANU) told SBS News.
"We've gone from being concerned about overpopulation worldwide to being concerned about an unsustainably small population for most parts of the world — that is a dramatic departure."
The 2024 revision of the World Population Prospects, which has been regularly updated by the UN since 1951, is being released on World Population Day, which seeks to raise awareness of global population issues.
We've gone from being concerned about overpopulation worldwide to being concerned about an unsustainably small population for most parts of the world — that is a dramatic departure.Dr Liz Allen, Australian National University
UN under-secretary for economic and social affairs Li Junhua said the birth rate in some countries was lower than previously anticipated, and there were also slightly faster declines in some high-fertility regions.
"The demographic landscape has evolved greatly in recent years," he said.
The world’s population is now expected to peak in the mid-2080s, growing over the next 60 years from 8.2 billion people in 2024, to around 10.3 billion. It is projected to drop to around 10.2 billion by the end of the century.
The probability of population peaking this century is estimated at 80 per cent. A decade ago, the UN estimated the probability at 30 per cent.
Li said it was a "hopeful sign" that the world's population was now expected to peak earlier and at a lower number than before, saying that this could mean "reduced environmental pressures" due to lower overall consumption.
"However, slower population growth will not eliminate the need to reduce the average impact attributable to the activities of each individual person."
Lower than expected levels of fertility
The earlier population peak has been attributed to lower-than-expected levels of fertility in some of the world's largest countries, particularly China, where population growth has already peaked.
Globally, women are having one child fewer on average than they did around 1990.
The number of people in China, along with countries like Germany, Japan and the Russian Federation is now expected to fall over the next 30 years.
China's population has already peaked and is expected to keep falling until the end of the century. Source: SBS News
Australia's population is expected to keep growing into the next century. Source: SBS News
The UN said eliminating births among girls under age 18, which still made up 3.5 per cent of births worldwide, had the potential to slow population growth for countries in sub-Saharan Africa.
The proportion of older people in Nigeria is lower than in other countries. Source: SBS News
Not all countries could sustain Australia's migrant-intake levels
Australia is one of around 50 countries and areas, where immigration is projected to be the main driver of population growth through to 2100. Other countries include Canada and the United States.
By 2100, Australia is expected to be home to 43 million people, much larger than the .
Almost 60 per cent of Australia's current population is aged between 20 and 64 years. While this is expected to drop slightly, more than half will still be of working age by 2100.
In countries like Japan and Italy, those of working age will shrink to less than half of the population by 2045 — just over 20 years.
China's working-age population is expected to be as low as 43 per cent by 2100.
The working age population in Japan will shrink to less than half its population by 2045. Source: SBS News
"For China for example, to use migration in the same way as Australia does to make up for its low fertility, it would have to have about 10 million migrants coming into China every year," he said.
"That's absolutely impossible ... Australia is small enough that the level of migration we have is okay."
'More competition for skilled migrants'
KPMG urban economist Terry Rawnsley said relying on immigration to boost the working population isn't necessarily a problem but it meant that surges in international arrivals could potentially have a larger impact on issues like housing affordability, compared to a gentle increase in births.
If Australia didn't want to rely on migration, it could look at boosting the fertility rate, although this would likely require addressing challenges such as housing affordability so that people felt financially secure enough to have children, Rawnsley said.
The number of live births per woman in Australia is around 1.7, lower than the 2.1 babies required to maintain a constant population size over the long term without migration.
Australia's fertility rate has fallen below the replacement rate to maintain the size of its population.
Rawnsley said increasing the fertility rate in Australia would not solve current labour shortages but it would reduce future risks around relying on migration for future stability.
"The whole world is ageing — and there's just more and more competition for skilled migrants across the world," he said.
Increasing immigration around the world has also led to rising xenophobia and other concerns, Allen adds.
Housing affordability could be key to boosting fertility rate
Allen lists four main issues impacting young people's decisions on whether to have children. They include the housing affordability crisis, rising cost of living, secure employment, and concerns over the impacts of climate change.
"Based on the current trends around these crises, we anticipate that [these] crises won't get better and won't resolve on their own, they need some intervention," she said.
She said young people needed to feel secure and comfortable enough about their future to have children and boost the country's fertility rate.
Housing affordability is impacting young people's decisions about having children. Source: AAP
"If we want to grow that working age population [and] encourage people to have children, we really need to have affordable housing ... whether they're living here currently or looking to migrate to Australia."
Unequal household duties could also be holding women back
Allen said women in Australia were being asked to "carry the burden of our future", maintaining a position in the paid workforce while also raising children.
"Trouble is, women still do the largest share of unpaid work [in the home]," she said.
The UN noted that unequal division of domestic work within households and inadequate child and family welfare support could prevent or discourage women and couples from having larger families, even if they want them.
Women still do the largest share of unpaid work.Dr Liz Allen, Australian National University
Although the UN has directed its comments at countries where populations have peaked or are expected to peak in the next three decades, which does not include Australia, Allen believes it's something Australia should also be looking at.
Allen said there needed to be a conversation about gender inequality and this included allowing men to fulfil roles they desired, including being the primary caregiver of a child.
Ensuring there is gender equality from the playground to the boardroom would create an environment where people could have children if they wanted, "without compromising on their own identity", she said.
The UN believes adopting policies aimed at balancing family and work life could encourage more women to enter the workforce, support people to have children and increase economic security for men and women at older ages.
Options include paid parental leave, flexible working arrangements, affordable childcare, services for aged care, and encouraging the equal distribution of household chores.
Australia cannot afford to be complacent about ageing population
Allen said shrinking populations were not a problem in their own right, although there were issues Australia should be mindful of.
"If Australia isn't attentive to its demographic headwinds, we can look no further than Italy or Greece, to [see] what the future holds," she said.
"[It's] a population where elders are the critical mass and young people are struggling to get a go."
The UN predicts the number of people aged 65 years or older will surpass the number of children aged under 18 years old by the late 2070s.
This puts more stress on working-age people to earn enough income to support those on pensions, and to cater to growing demand in the health and aged care sectors.
Rawnsley said part of the challenge was that people were living longer and spending more years in retirement.
Australians are living longer and spending more years in retirement than before. Source: AAP / Glenn Hunt
"That's not occurring in Australia, not to the degree that many hypothesised," she said.
While the challenges Australia is facing are not as bad as in other countries, partly because it can rely on immigration to help prop up its population, we can not afford to be complacent, Allen said.
"We need to be strategic about ensuring that we have all of the right elements in place to ensure population wellbeing down the track."
Technology could help address the challenges of an ageing population
Other options to address the challenges of an ageing population involve encouraging people to work longer or to start working.
Technology can also be used to improve productivity so more income can be generated for the same number of working hours.
Rawnsley said the government should look at providing more incentives through the tax and transfer system to encourage people to work more hours without losing their government payments.
More support was also required to train or upskill older workers to use technology such as ChatGPT so they could stay in the workforce for longer.
Training older people to use new technology can help them stay in the workforce for longer. Source: Supplied
There had also been a push to improve the health and wellbeing of older people, and keep them active in their own homes, which can reduce long-term health costs, he said.
McDonald notes that the only other alternative would be to encourage more deaths, "but we're not trying to do that, I don't think, in very many places".
Women have a longer life expectancy
The UN noted that women outnumber men at older ages in almost all populations because they live longer.
It said policies should address women's longer life expectancy by ensuring access to retirement benefits, prioritising gender-specific healthcare needs and strengthening social support systems to reduce caregiving burdens.
Allen said ageing was a "feminised phenomenon" that would give rise to a raft of health and social consequences.
"I don't think as a society we've got to that point where we actually truly understand the feminised nature of ageing," she said.
I don't think as a society we've got to that point where we actually truly understand the feminised nature of ageingDr Liz Allen, Australian National University
Allen said the social and emotional needs of lone-person households, particularly those consisting of women, needed to be addressed so that loneliness and isolation did not cause harm.
She said the conversation often came down to housing and how we build cities and infrastructure.
"So, in fact, investing in that feminised nature of ageing can have flow-on consequences for young people as well."
