Global Population Sustainability: What is the limit?

It’s World Population Day and as of today, there are over 7 billion of us sharing this planet.

How did we get here?


After rising very slowly for millennia, population figures were just starting to take off in the 1700s. A century and a half later, the world’s population had doubled to more than a billion. It took another century, between WWI and II, to double again to two billion, and the acceleration since then has also been astounding.

Before 1900s, no human had lived through a doubling of the human population, but there are people alive today who have seen it triple (source: NGM).

So, why the sudden surge?

Many things happened, simultaneously and progressively. Society has changed: more medical innovations and preventive care (including sex education, contraceptives and family planning), better transportation means and efficiency (getting medicine and medical personnel to the source of need), and a more ‘connected’ world (dissemination of knowledge and information about medical science) enabled us to stop the spread of communal and contagious diseases, advance health treatments, increase life expectancy (from 35-40 years in 1952 to 65-80 today), and make improvements in gender equality (women gaining access to education and labour force).


Here is one fun quick lecture and a cool visualization of statistical data of the changing world:


By the early 1970s, fertility rates around the world had begun dropping faster than anyone had anticipated. Since then, even though the population growth continued to grow, the population growth rate has fallen by more than 40 percent.

But where are we heading, in terms of population growth projection?

According to Hans Rosling, global health expert and a co-founder of Médecins Sans Frontièrs, we have reached peak child. The number of children is not growing any longer in the world. And the world population will stop growing at 10 billion. Here’s how:

There are ~ 2 billion children in the world right now,

~ 2 billion young people age 15 to 30,

~ 1 billion age 30 to 45,

~ 1 billion age 45 to 60,

~ 1 billion at 60-plus.

We are now in a process known as “the big fill-up.”

A rate of two children per woman is considered the current replacement rate for a population, meaning relative stability in terms of total numbers. Rates above two children indicate populations growing in size and whose median age is declining. Rates below two children indicate populations decreasing in size and growing older.

As the old die, the rest grow older and have an average number of children.

The total median fertility rate for the world is 2.59, down from 5.0 in 1965.

The average number of children per woman has been declining over the past 4 decades; it’s now at 1.3 in the developed world and 3.9 in the developing world. This indicator shows the potential for population change of a country (aging population, children, youth, employment, education and economic opportunities, etc).

Global fertility rates are in general decline everywhere, though the trend is most pronounced in industrialized countries where populations are projected to decline dramatically over the next 50 years (such as Europe, individual countries and the union, overall). Such societies (EU, Canada, Australia) are also dependent on immigrants for its population balance, mostly immigrants from poorer nations with different (and more sizeable) family cultures.

According to the CIA World Factbook, the average number of children per woman is the highest in Niger (7.03!), with other African nations closely following suit (in fact, of the top 40 high-fertility countries, all are Sub-Saharan African nations, with the exception of Afghanistan, the Gaza strip, and Yemen). But, the 2050 projections estimate that the number of children per woman in African nations will decline to below 4. This is the region that will shape the size and distribution of world population this century.

41% of the world’s population live in ‘low-fertility’ countries, where women bear less than the replacement rate (source: UN). The lowest rates are found in Singapore (0.79), closely followed by the neighbouring South-East Asian nations (Macau  – 0.93; Hong Kong – 1.11, Taiwan – 1.11).

Other notable statistics: UK (1.9), Russia (1.61), EU (1.58), USA (2.06), Canada (1.59), China (1.55), Japan (1.39), India (2.55), and Brazil (1.81).

Before China implemented its coercive one-child policy, women were bearing an average of 6 children each as recently as 1965! (source: NGM) – which clearly reflects on China’s population size today.

Now, what’s the pattern? Women in developed countries with healthy, wealthy, educated and urban populations bear fewer children, less than the replacement rate, while women in underdeveloped and developing countries with unstable economic, political, and security situations bear more children.

Additionally, life expectancy, child mortality rate, and other health factors play an important role in their decision to have more children, as do the availability and affordability of contraception, family planning, women education and labour participation, and regional cultural norms. Therefore, the problem does not lie in high fertility rates, but the health, nutrition, social support structure, and conditions these populations are living in.




Natural resources and climate change

Addressing population growth is quite complicated and challenging. Changes in population (its volume, age, and distribution) affect all other aspects of life, including food and water requirements, health, employment, economy, productivity, transportation, urbanization, social structure, etc.

Extremes are everywhere around us: glacier melting, sea-levels rise, droughts, floods, unpredictable/ erratic/ unseasonal weather affecting crops, food quality, obesity, famine, more demand, more technology, loss of land, land-use, manufacturing, processing, transportation, energy needs and distribution, and CO2 emissions.

Our natural resource use is inefficient and, as our supplies plummet, so does their quality.

Climate change is a serious threat to water availability and increasing food production. Changes in environmental conditions are likely to lead to major changes in agricultural patterns due to long-term climate imbalances, and result in increased prices and diminishing quality and quantity of food produced world-wide, thus affecting provisions necessary for growth, good condition and health of entire nations and regions.

Sixty-six nations are currently unable to meet their population’s food needs. They may soon be contributing to ‘environmental refugee’ or ‘climate migrant’ movements.



As our natural environment keeps changing, our social structures change as well. 1) Improving access to clean water, 2) adequate sanitation and 3) solid waste disposal can immensely change the quality of life of people around the world. These three are the right of every human being; they are reasonable, basic, simple and, by all other accounts, affordable.

There are still massive cases of transmittable diseases that are relatively easy to prevent or treat. But they are costly. Still, preventative medicine is more cost-efficient than treatment medicine. Improving these three components can help reduce the risks of the spread of illnesses.

A healthy society is more productive and progressive.

According to the World Health Organization, typical environmental health issues and adverse health consequences due to increased pollution may include the spread of vector-borne diseases, aggravation of respiratory diseases, damage to the lungs and respiratory system, severe reduction of oxygen-carrying capacity of the blood, digestive problems, skin cancer and cataracts, and compromised food production.



Agriculture/ Food availability and distribution 

The scientific and technical knowledge needed to solve the world’s growing food crisis already exists, but transferring it to small farmers in a way that is usable remains a serious challenge, as is getting governments to adopt the necessary policies to facilitate this.

Increasing food production in Asia, Central America and Sub-Saharan Africa is vital to meeting the needs of a world population expected to hit 9 million by 2050. Small-scale farmers make up most of the world’s food production.

Helping these farming families increase production in a sustainable way and sell more crops is the most effective way.

It is also necessary to focus research on farmers’ concerns rather than just presenting findings and expecting them to adopt the recommendations.

Most of the solutions that are needed are known, but there hasn’t been consensus between policymakers and farmers on how best to adopt them.

However, there is one point that is largely forgotten when accounting for population growth and the demand for food production, and that is EFFICIENCY. This is a fact: With current agricultural surpluses of developed nations we can feed the growing population. Western nations already produce twice the amount of food that they need, or 3-4 times the necessary amount, if we account for the crops fed to livestock for the production of animal products. Only 44% of the total global food production is what we actually feed on at the moment (source: TED)

Some population analysts are already sounding the emergency alarm. Planners and policy-makers can no longer make decisions based on arising needs. Instead, we need to already look to the future and the impending requirements, in order to be able to meet them.

In fact, as advances accelerate, so do the problems, unfortunately. Simply put, we are already living beyond our means.

Written for and published by Living Green Magazine.

Sources and further info:

Hans Rosling: Religion and babies – TED

Melinda Gates: Let’s put birth control back on the agenda – TED

Hans Rosling: Global population growth, box by box – TED

Hans Rosling: Stats that reshape your worldview – TED

Robert Kunzig: Population 7 Billion – National Geographic Magazine

Elizabeth Kolbert: Enter the Athropocene – Age of Man – Nat Geo Mag

Danny Dorling: A global population of 10 bill is nothing to worry about – Guardian

Andrew Simms: We keep moaning about population, but ignore consumption habits – Guardian

Stephen Emmott: Humans, the real threat to life on Earth – Guardian

Thomas Pogge: Unfair Share – the RSA

People and Possibilities in a World of 7 Billion – UNFPA 2011 Report, PDF

United Nations: World Population to 2300 – 2004 Report, PDF

One thought on “Global Population Sustainability: What is the limit?

  1. Again: amazing & frightening!
    I like how you distinguished issues and presented the main global topics for (further!!!) consideration and solutions.
    Or has that “further” already been happening?
    A food for your thought, if I may… to offer us some argumentation on WHY and what is really behind that women in developed countries with healthy, wealthy, educated and urban populations bear fewer children.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s