There was a large increase in human population after the Industrial Revolution mainly because death rates fell sharply while birth rates stayed high for many decades, especially in industrializing countries.

Before the Industrial Revolution

For most of history, world population grew very slowly because high birth rates were offset by high death rates from famine, disease, and poor sanitation. Around 1700, global population is estimated at roughly 500–600 million, and it only reached about 1 billion by around 1800.

What changed after industrialization?

After the Industrial Revolution began in the 18th century, several linked changes reduced mortality without immediately reducing fertility.

Key factors included:

  • More food : Agricultural improvements and later synthetic fertilizers greatly increased food production and made famine less frequent.
  • Better sanitation : Clean water, sewage systems, and basic public health measures sharply reduced deaths from infectious diseases, especially in cities.
  • Medical advances: Vaccination, antibiotics (later), and improved medical knowledge lowered infant and child mortality.
  • Rising living standards: Industrialization generally raised incomes in the long run, improving nutrition, housing, and clothing.

Demographic transition effect

Industrialization triggered what demographers call the demographic transition : first death rates fall, but birth rates stay high, so population grows rapidly.

Typical pattern:

  1. High births, high deaths → slow growth (pre‑industrial societies).
  1. Deaths fall (better health, food, sanitation), births still high → rapid population growth.
  1. Births eventually fall (urbanization, education, contraception) → growth slows again.

In 1800 there were about 1 billion people; by the early 21st century, world population had risen to several billion, largely due to this phase of low mortality and still-elevated fertility that industrialization set in motion.

Why it was so dramatic

The increase looks like an “explosion” because:

  • The rate of growth rose sharply; it took many centuries to go from about 0.5 to 1 billion, but only about two centuries to jump from 1 to well over 7 billion.
  • Mortality fell quickly thanks to technologies (public health, vaccines, modern agriculture) that spread worldwide, while cultural and economic reasons for having many children changed more slowly.

In short, the Industrial Revolution and its aftermath created conditions where many more people survived to adulthood and lived longer lives, while families continued to have many children for some time, driving a rapid surge in human population.