The United Nations has projected the world’s population to reach 8 billion people on November 15 which is seen as a “milestone in human development” rather than an imminent danger of unprecedented food and energy crises worldwide.

The last billion was reached in just 12 years to demonstrate unprecedented growth due to “the gradual increase in human lifespan owing to improvements in public health, nutrition, personal hygiene and medicine”, according to the UN World Population Prospects 2022. 

However, the growth is a bit slowing and it will take approximately 15 years -- until 2037-- for the global population to reach 9 billion, according to the report.

Countries with the highest fertility levels tend to be those with the lowest income per capita. 

“Global population growth has therefore over time become increasingly concentrated among the world’s poorest countries, most of which are in sub-Saharan Africa,” it said.

So, how did we get to this milestone?

According to the renowned research and data website Our World in Data, it took all of human history until 1803 to reach the first billion in population. 

The next billion took 124 years, the next 33 years and more recent billions have come every dozen or so.

That results in a hockey stick curve in the global population growth measured since 10,000 Before Common Era when the estimated human population was just 4 million.

Human population growth started going exponential around the time when new technologies and farming conventions took root in the 17th century, making it possible to grow the food supply at an unprecedented pace, according to Our World in Data author Jeff Desjardins.

Indonesia, home to around 275 million people, has the fourth-largest population in the world after China (1.43 billion), India (1.41 billion), and the United States (337 million).

India's population is estimated to grow to 1.5 billion people in 2030 and surpass China as the world's most populous nation.