According to the United Nations, the world is now home to 7 billion of us. The milestone child was born on 31 October 2011, it is claimed, although the precise date is unsurprisingly unknowable.

Such is the margin of error in population growth modelling that there is in fact a window of several months around this date. The United States (US) Census places this date sometime in March 2012. Nonetheless, the UN’s announcement prompted a boom in babies who were anointed the 7 billionth child born.

The most famous of these is Danica Camacho, born in the Philippines. A representative from the United Nations Population Fund attending the birth in Manila emphasised the need for all countries to make proper provision for a growing population and to ensure access to health and education, laying the foundation for economic growth.

In India, a number of non-governmental organisations (NGOs) seized on the day to draw attention to selective abortions of females — a practice that has led to severe gender imbalances in many Indian states, falling as low as 877/1,000 in Haryana and only 830/1,000 for those born in the last 6 years according to India’s 2011 Census. A ward full of baby girls in Uttar Pradesh was the choice of location for one NGO, whilst Plan International designated Nargis, a girl born in the same state.

The world is welcoming each new billionth person at an ever-increasing rate. It has taken just 13 years to add the latest billion people to the planet. This figure predictably cues a popular commentary about how the planet is heading for a perilous future. Understandably, this was not the line from the UN representative in Manila who emphasized the need for all countries to plan for their population. However, this planning is typically focused on securing more resources, despite the fact that consumption and not just population should be taken into account when measuring the sustainability of human existence.

Depending on whom you ask, population is a problem for a variety of reasons. The popular refrain from environmentalists is that there are too many people chasing too few resources and there is already unequal access to the resources that exist. We will need 70% more food by 2050 to keep up with an increased demand for food.

This is not because the population will not increase, but rather because consumption will increase 70% as more and more people join the ranks of the middle classes in developing countries.

However, talk to economists and they see a different population problem — that of not enough people, or at least, not enough young people.

Get rich or die trying

The burning question on the minds of many economists is whether China will get rich before it gets old. The demographic dividend is a theory that says a falling death rate produces a dominant cohort of working age people who can advance the economic growth of a nation.

Whilst the first part of this equation is a self-fulfilling prophecy, the second part is not. The one child policy has given the most populous nation on earth less of a demographic dividend than it would have expected otherwise and concern is growing that China’s golden period of large scale economic expansion will wane before it can reach the entire country.

Many parts of East and South East Asia are ageing quickly. The only way to avoid an ageing population is to endlessly maintain a higher fertility rate than was previously the case. The fear over declining populations in countries who have spent that dividend are now considering the next logical policy challenge: how to add more young people into the economy.

On an individual country basis, probably the simplest method is to allow immigration of people who are already on the planet. Large-scale immigration was popular in emerging new worlds from the start of the 20th Century. The US issued a utopian call for the poor and the hungry to build a superpower.

On the other side of the planet, Australia was oppressed by the ‘tyranny of distance’ from global markets and saw it as a matter of basic survival to ‘populate or perish’. This attitude recently found resonance with the Big Australia policy of former Prime Minister Kevin Rudd, later denounced as a scheme based more on profit than population.

Low birth and marriage rates are often being reported for industrialised East Asia, in particular Japan. This trend is now also beginning to be reflected in the US where more than half of adults will be unmarried. In the absence of immigration, making babies is the only other way to increase population. No wonder the nervous South Korean government sees fit to ensure civil servants are given an early night to get them in the mood.

No country for young men?

The fact of the matter is that in the developed world it is easier to make an old person than a young one. As economies develop, birth rates decline, fewer young people are added to the population and over time, the proportion of old people increases. This effect is compounded when coupled with longer life spans.

In the West, the post-war ‘baby boomer’ spawned the ‘me’ generation that gave us counter-culture, hippies and yuppies, along with various environmental and financial crises, and largely dictated much of what we understand to be contemporary western culture. Will the generation that typically put their parents in nursing homes (and are starting to age themselves), allow themselves to be put in homes, or will they use their demographic might to lobby for laws that give older people greater pension protection and other rights?

With fewer children to look after ageing parents, Singapore’s Maintenance of Parents Act of 1995 aims to enforce filial piety by allowing parents to claim maintenance from their offspring. Some 400 parents (mainly fathers) applied in the first three years following the act, for example.

Yet young people in themselves are not a solution if there are no jobs. High unemployment, especially amongst the young, is a worldwide phenomenon. A recent report indicates that globally, we will need to find 600 million productive jobs over the next decade to sustain not just economic growth but even social stability.

One only needs to look to the origins of the Arab spring to see the power of disaffected young men in particular. All over the world, the young still tend to flee the countryside whenever they can for the big cities. Declining towns in much of the Midwestern US have tried giving away free land to lure jaded city dwellers back. In Japan, even the world’s signature megalopolis Tokyo is projected to age significantly by 2050. Meanwhile the need to repopulate rural areas also comes in the context of saving farming in the name of national food security.

Get ‘em young

Looking behind the number 7 billion reveals many different worlds, different challenges, and a raft of seemingly contradictory policies that are being used to address them. Despite the general consensus that a lower population is better for the planet, we find many places are trying to grow their population to keep their economies afloat or support ageing populations.

In other places, economic growth is driving down fertility but driving up consumption, resulting in increased pressure on the Earth’s resources. Finding new economic models that don’t rely on endlessly adding population and consumption to keep an economy growing would be useful. But to do this we need to accept that the economy may be smaller or more inter-generationally connected and see the elderly as a resource rather than a burden.

Notwithstanding these considerations, the birth of the world’s 7 billionth person only 13 years after the birth of the 6 billionth reminds us that we are overwhelmingly a youthful planet. And with youth comes the hope of a better-educated generation more adept at finding innovative solutions to the monumental challenges we face. Therefore, the education they receive is critical for finding better ways to live, not just for our children and their children but increasingly for our parents and grandparents.