7.4 Billion Earthlings on One Planet: Trends of the Past 60 Years
Background
The world population was estimated at 7,441,490,775 as of 9am on August 6th, 2016, according to Worldometers.
7,441,490,775 is far from a small number. I cannot resist doing some thought experiments.
Assume the average height of human (including men, women, and children) on Earth is slightly more than 1 meter, and each person stands on the shoulders of another one to build a ladder sticking to the blue sky. Given the circumference of Earth at the equator, which is about 24,874 miles, the ladder of height 7,441,490,775 meters (4,623,928 miles) can wrap around the Earth’s equator 186 times! If we collectively stack ourselves towards Mars, then the ladder height is 3.3% of the mean distance from Earth to Mars (140 million miles).
If each of us stands straight within a square of 1 square yard in area, one besides another, to form a massive infantry square, the entire world population then occupies 2,402 square miles, which is equivalent to 105 Manhattan Islands, or 7.9 New York City, or 21% of the entire Hawaii Islands.
In computer science terminology, if each person maps to one byte of memory of your laptop, then the entire population consumes around 7.44 GB of memory.
Isn't this a huge number? Don't forget, as you take 3 minutes to think through these facts in your head, hundreds of babies have been born.
Motivation
As we analyze the past 60 years of human history, we can see that different regions of the world have shown distinct trajectories of population growth. I am especially interested in investigating these growth trends, and answering the following questions:
- What are the most populous countries/regions in the world?
- What does the population growth look like in different countries/regions over the last 60 years?
Source code and demo
The Shiny app can be found here: https://sundeepblue.shinyapps.io/world_population_explorer/
Github code: https://github.com/sundeepblue/world_population_explorer
The dataset used to generate the Shiny app can be found in [5].
If the world were 100 people
If the world were comprised of only 100 people in 2015, there would be 60 people in Asia, 15 in Africa, 11 in Europe, 14 in America (9 in South America, and 5 in North America), as shown below. The infograph below was generated using https://infogr.am/.
Population by region
75% of the earth is covered by ocean, and only a portion of the remaining 25% of all lands are habitable for humans to live and flourish. Overall, the distribution of the population in the world is largely affected by various factors, including the territorial landscape, geographic environment, and regional economic level, etc. Our mother planet, superimposed with population across all 232 countries/regions is shown below.
Entire world
All men are created equal, but not all regions where men live develop equally:
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- The world population in 2015 was nearly triple that of 1950.
- Growth is the main theme. But less developed countries/regions have larger population growth rate than more developed regions.
- The population of developed regions (all regions of Europe plus Northern America, Australia/New Zealand, and Japan) is much smaller than the rest of the world.
- The population of high-income countries does not grow as fast as the rest of the world.
Milestones by the billions
The global population reached 4 billion in 1974, 5 billion in 1987, 6 billion in 1999, and 7 billion in 2012. Note that there is no exact day or month the world’s population exceeded those milestones since the worldwide population census was usually conducted every 5 years. It is worthwhile to know that United Nations estimates that the world population will reach 8 billion by 2024, and will possibly reach 9 billion by 2037.
Asia
Asia is the most populous continent, and the Asian population is equivalent to more than half of the world population. We are especially interested in looking at eastern and southern Asia because China and India are the world’s two most populated countries. They together contributed around 37% of the world’s population in 2015.
Eastern Asia
China and Japan are two of the most populous regions in eastern Asia, but from the visualization, China shows larger growth than that of Japan.
Overall, the curve of China is increasing over the last 60 years since 1950. But when looking closely into the curve, we may find the increase is not at the same speed.
(Graph courtesy of worldometers [3])
It is not hard to notice that there were three subtle "valleys" along the population curve of China between 1960 and 1990. From the Yearly Population Growth Rate plot, we see three major drops in population growth rate around 1959, 1972, and 1988, caused by Great Leap Forward, Cultural Revolution, and the one-child policy, respectively.
As developed countries, Japan and Korea do not have a large population base, and there is no sign of large increases in either country.
Southern Asia
India has the largest population in southern Asia, and the second largest population in the world. As described in previous sections, Pakistan and Bangladesh rank 6th and 8th in world's population in 2015.
Northern America
In Northern America, the USA has the largest population, and Canada is the second runner. The population of Canada has a constant speed of growth, whereas the population of US had subtle "valleys" over the last 60 years, indicating an unstable growth rate.
Top 10 populations by country
Three years, namely 1955, 1985, and 2015, were investigated here to illustrate how the top 10 countries evolve in population.
1955
In 1955, China ranked 1st and accounted for 20% of world population. The Russian Federation ranked 4th in the leaderboard, and accounted for 4.05% of the world population.
1985
In 1985, Indonesia surpassed the Russian Federation, and ranked 4th in the ladder. Germany, UK, and Italy were all squeezed out by Bangladesh, Pakistan, and Nigeria.
2015
In 2015, Mexico kicked in, leaving Japan out of the top 10. China, India, and US remained the top 3. Surprisingly, the population of Russian only increased by 481,150 people from 1985 to 2005. But digging into Russian history in the past 20 years, we know the root cause: dissolution of the Soviet Union.
Should we worry about overpopulation?
Concern about overpopulation has lasted for decades. Researchers have developed many models to predict the future world population. Debates about overpopulation still echo in both academic communities and among common people.
The good news is that, globally, the population growth rate has been steadily declining from its peak of 2.19% in 1963. Nevertheless, growth remains high in Latin America, the Middle East, and Sub-Saharan Africa [4], and no one can exactly foresee what the future population will be.
(Graph courtesy of [4])
Conclusions
Based on the visualization of this Shiny project, the following conclusions can be drawn:
- The human population has continuously increased over the last 60 years.
- Growth is still the constant theme across all regions, both poor and rich.
- 5 out of the top 10 populous countries in are developing countries in Asia (China, India, Indonesia, Pakistan, and Bangladesh).
- Developing countries tend to have larger population base and higher growth rate than developed countries.
- The most highly developed regions have lower population growth rates.
- The overall growth rate of world population is declining, and will continue to decline in future decades.
References
[1] http://www.averageheight.co/average-male-height-by-country
[2] http://www.space.com/16875-how-far-away-is-mars.html
[3] http://www.worldometers.info/world-population/china-population/
[4] https://en.wikipedia.org/wiki/Human_overpopulation
[5] https://esa.un.org/unpd/wpp/Download/Standard/Population/
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