The population bomb

The total world population will reach 9.6 billion by 2050. Photo / Michael Craig

Robert Malthus may not have been the first to predict runaway population rise, but he was smart enough to grab the naming rights.

The English cleric argued that rather than humanity being on an ascending path to perfection, population increases would eventually become unsustainable unless checked by war, famine and disease, or more positively by birth control and celibacy.

When he first published An Essay on the Principle of Population in 1798 the world was six years shy of a billion human inhabitants.

By the end of the 19th century the population of the world was about 1.65 billion, and New Zealand was 33,000 people short of its first million.

By 1950 there were 2.5 billion souls and the 21st century started with 6.1 billion people consuming an ever-increasing share of the world's resources.

The United Nations Population Fund estimated the 7 billion mark was passed on October 31, 2011. It is now more than 7.3 billion.

The 8 billion mark should be reached in early to mid 2024, as the annual growth rate is slowing - it peaked at 2.19 per cent in 1963 and now stands at about 1.14 per cent.
The UN projects global population will reach 9.6 billion in 2050 and then stabilise a decade later at 10 billion.

That's without the sort of catastrophe Malthus predicted would trim the total.
So where are these people, or where will they be?

One answer is developing regions, especially in African countries which still have high fertility as well as countries with large populations such as India, Indonesia, Pakistan, the Philippines and the United States.

The UN expects India's population to match China's in 2028 at around 1.45 billion, and continue to grow as China declines.

Nigeria's population is expected to surpass that of the United States before the middle of the century and then keep growing until it could rival China by the end of the century as the world's second most-populous nation.

Tanzania, Pakistan, the Democratic Republic of the Congo, Ethiopia, Uganda and Niger could also top 200 million each by 2100.

Another answer to the question is more people will live in cities and towns, as more than half of the world's population does already.

While the UN projects global population to increase by 2.4 billion between 2010 and 2050, in the same time span depopulation of rural areas means the urban population is expected to grow by 2.7 billion, with 94 per cent of that growth concentrated in less developed regions.

Some of that is driven by the pull of urban opportunity, but there is also push as corporations and hedge funds buy up large tracts of land, water rights and other strategic assets for industrialised farming.

Many studies have drawn a link between urbanisation and lower birth rates, but it's not quite that simple.

A working paper for the London-based International Institute for Environment and Development by Brazilian demographers George Martine, Jose Eustaquio Alves and Suzana Cavenaghi says developed countries support massive family planning campaigns in high fertility countries as a way to tackle the alleged "population pressure".

Such programmes are credited with any population decline, whereas it's more likely that improvements in social and economic conditions create a climate where people want fewer children. It's at that stage they turn to family planning.

Important factors that motivate people to regulate their natural fertility include urban residence, education, infant and child mortality reduction, women's empowerment, wage labour, women's participation in the labour force, increased consumption aspirations and social mobility.

Seen that way, moving to town isn't a contraceptive. The Brazilians warn that while city life can provide people with real choices, "good" urbanisation is not occurring spontaneously and needs explicit, proactive attention from policymakers.

Unfortunately the opposite is happening. Policymakers see urban growth as problematic, and 82 per cent of developing countries have implemented policies to curb rural-urban migration.

Such policies intensify the difficulties that large contingents of poor people will encounter in looking for suitable housing and decent work opportunities, as well as accessing basic services of all kinds, including reproductive health.

Such negative policies actually promote unchecked expansion of slums, where a third of the world's population (including 3/4 of Africa's) now live.

Slum residence and higher fertility levels go together.

Lincoln University lecturer in urban studies Suzanne Vallance says major change at an economic and social level is needed to grapple with the challenges of the developing world's fastest-growing cities.

Dr Vallance attended the recent UN Future of Places conference in Stockholm, where 400 urban thinkers discussed issues such as public space, place making, and place governance.

She came back somewhat despondent, feeling people were just tinkering with the system rather than thinking about the institutional and governance models needed to deal with ever-expanding cities.

"We have a message coming from the right that we need market solutions, but there is no coherent or credible counter argument or viable alternatives to the marketisation of every problem and solution," she says.

One speaker who did impress her was sociologist Saski Sassen from Columbia University in New York, who looked at population, income distribution and wealth accumulation.
Sassen, who coined the term "global cities" back in 1991 to describe the impact of places like New York and Tokyo, argues the poor will increasingly be urban poor cut off from the most basic resource of subsistence land farming.

The responses could be at one end of the scale more equity, to ensure what is available is shared, and at the other end more militarisation and containment of increasingly unruly and starving populations.

"She is saying the rich are buying up the productive land, the poor are displaced to urban areas, so the wealthy who can afford it are buying the right to survival," Vallance says.

Global challenge - population growth

Photo / Getty Images

Total world population 9.6 billion by 2050. Up from today's 7.3 billion, as estimated by the United Nations Population Fund.

1.75% is the annual increase in global food production needed to double food supplies by 2050. The Global Harvest Initiative says the current rate is 1.69%. Compounded over 40 years, that means missing the target by six per cent, which means the world can't feed itself.

More than 1 billion people do not have access to clean drinking water. Another 2.7 billion find water scarce for at least one month of the year. Aquifers are being depleted faster than they can be replenished. At the current rate of consumption, 2/3 of the global population will face water shortages by 2025.

Increasing global populations put more pressure on climate change as forests shrink and emissions increase. Likely outcomes include high commodity prices, the collapse of fisheries, loss of species' habitats and natural disasters.

Over the past 16 years, India's middle class increased from just one million to 108 million people. That figure could swell to 1 billion or 84 per cent in another 16 years.

Fertility levels vary widely around the world. Among the 30 OECD countries, total fertility rates ranged from 1.1 in Korea to 2.2 in Mexico and Turkey. New Zealand's rate in 2008 was 2.2 births per woman. The rates for Māori and Pacific women were 2.8 and 3.0 respectively, and other ethnicities had a total fertility rate of 1.8. Currently about two in five births in New Zealand have a Māori or Pacific parent.

The country with the highest fertility rate is Niger, with 7.6 births per woman, followed by Mali, Burundi, Somalia and Chad, Uganda or Nigeria, depending on the source. Of the top 30 countries with the highest birthrates, only Timor Leste and Afghanistan are outside Africa.

Countries with fertility rates close to 1 or below include South Korea, Singapore, Hong Kong, Macau, and Bosnia and Herzegovena.

The most recent projections from Statistics New Zealand are that the population will grow from the current 4.5 million to 5 million, give or take 100,000, by 2025, and has a high probability of being over 6 million by 2050. That contrasts with a 2002 projection of just 4.8 New Zealanders by 2050.

Population growth will slow as New Zealand's population ages and the gap between the number of births and deaths narrows. By 2041 a quarter of New Zealand's population could be over 65, compared with 14% now, and there could be between 220,000 and 270,000 people over 85, compared with 78,000 now.

Nigeria is heading towards 1 billion people, and Tanzania, Pakistan, the Democratic Republic of the Congo, Ethiopia, Uganda and Niger could also top 200 million each by 2100.

This global challenge series has been made possible with support from Lincoln University. Lincoln University is among our more progressive on these issues, with three overarching organisational goals; to feed the world; protect the future; and live well. It's with these three goals in mind that every Lincoln course is now designed, and first and second-year students are required to undertake courses in understanding global challenges and the opportunities that lie in solving them.

Like what you see? For weekly Element news sign up to our newsletter. We're also on Facebook and Twitter.