The Interesting History of the World’s Population

Humanity has taken over the world. Every year, the population of the world is expanding by 83 million people. As of writing, there are already 7.6 billion people in the world. But population trends are mostly uneven – while some countries are expanding exponentially, some are shrinking. But have you ever wondered how our population grew to this number? Here’s to show you a glimpse.

History of the World’s Population

The history of the world’s population is difficult to track, and estimates of the world population are possible only since the Age of Discovery, which lasted from the 15th century to the 17th century. The earliest estimates of the world’s population date to the 17th century. In 1862, William Petty estimated the world population at 320 million, while modern estimates range twice to close this number. By the late 18th century, the world population has increased to one billion. It’s hard for estimates to be better than rough approximations, as even the modern population estimates contain uncertainties by around 3% to 5%.

Ancient History

Around 10,000 BC, the population has ranged between 1 million to 15 million. Genetic evidence suggests that about 70,000 BC, humans have gone through a population bottleneck of between 1,000 and 10,000 people, according to the Toba catastrophe theory. In the 4th century AD, it is estimated that around 50-60 million people existed in the combined eastern and western Roman Empire.

The Plague of Justinian between the 6th and 8th centuries AD was one of the earliest and deadliest plagues in history that caused a massive drop in population. This plague that happened during the reign of the Roman emperor Justinian caused the European population to drop around 50%. In 1340, Europe’s population was more than 70 million.

The Mongol invasion began in the early 13th century, and it killed off vast segments of the population. The Mongol empire systematically conquered modern-day China, Russia, Korea, Burma, all of Central Asia, among many other countries. And they did not conquer gently – the Mongols may have killed as many as 18.4 million people in East Asia alone between 1211 and 1337. At that time, the population of the world was around 360 million.

During the 14th century, the Black Death pandemic swiped away the world’s population from an estimated 450 million in 1340 to around 350 to 375 million in 1400. The Chinese population had decreased from 123 million in 1200 to 65 million in 1393. This vast population decline is presumably caused by a combination of the plague, famine, and Mongol invasions.

Modern History

During the Industrial Revolution and the Agricultural Revolution in Europe, the life expectancy of children increased. Back then, it was common for children to die before the age of five. From 1730 to 1749, 74.5% of children below five years old died, but this decreased to 31.8% from 1810 to 1829. Between 1700 and 1900, the population exploded from about 100 million to over 400 million.

The first half of the 20th century was marked by the two World Wars, famines, and other great disasters that caused large-scale losses in the population. In World War I, there were a total of 40 million military and civilian casualties. That number almost doubled in World War II, when about 70 to 85 million people perished, and that was about 3% of the world’s population, which was estimated at around 2.3 billion at the time. After the Soviet Union collapsed, Russia’s population significantly declined from 150 million in 1991 to 143 million in 2012, which was a downward trend compared to most of the world’s increasing population.

After vaccination was introduced and sanitation and medicine were greatly improved, the population growth in the West easily increased. The population in the United Kingdom increased from 10 million to 40 million during the 19th century and reached 60 million in 2006. Meanwhile, the population in the United States grew from around 5.3 million in 1800 to 106 million in 1920, and then more than 307 million in 2010.

Countries in the developing world also experienced extremely rapid population growth since the 1900s. China’s population exploded from 430 million in 1850 to 1.4 billion today. In the Indian subcontinent, there were about 125 million in 1750, and the population increased to 389 million in 1941. Today, India, Bangladesh, and Pakistan are home to about 1.76 billion people. After just a hundred years. The population of Brazil multiplied by ten, from about 17 million in 1900 to 176 million in 2000.

In estimation, the population of the world reached one billion in 1804. After 123 years, it increased to two billion in 1927. Then, the next billions happened all in the 20th century. The global population reached three billion in 1960, four billion in 1974, five billion in 1987, six billion in 1999, and seven billion in 2011.

Perhaps due to the awareness of the adverse effects of the population boom, developing countries are experiencing slow growth and even population decline. The urban population is now declining in developed economies. From 2012 to 2015, about 40 percent of Japan’s cities and 33 percent of Western European cities were declining in population. Also, population growth in the US experienced an all-time low in 2016, marking the lowest rate of growth since the Great Depression.


It is estimated that the population will rise to 8 billion by 2024, and is likely to reach around nine billion in 2042. By 2024, India is expected to overtake China as the world’s most populous country.

The population is still rising fast today, but it is expected to peak by 2070. This trend is projected to happen as a result of a population growth slowdown in Asia, the world’s fastest-growing region as of today. Also, declines in the population in Europe and stabilization in the Americas are expected, creating a world with a lot more older people than the young. It means more people will become less productive and will need constant care, which can dramatically affect and disrupt our economic and social structures.