Eight billion people – a new threshold crossed only 12 years after we reached 7 billion.

According to official estimates, Tuesday was the day the global population reached eight billion people. Recent population spikes, particularly in India and China, grew the number faster than population experts would have predicted fifty years ago, though they may be slowing now.

Population growth is an ever-increasing curve. It took hundreds of thousands or even millions of years for the human population to reach one billion, which is estimated to have happened in 1803. In 1927, after the first World War, we hit 2 billion. Three billion happened in 1960. Four billion was reached in 1974, and many predicted dire global consequences if we ever hit six.

Five billion hit in 1987, and six billion in 1999. Seven billion was in 2011 or 2012, based on different schools of estimation. And yesterday, population science tells us we became eight billion people sharing a planet.

The intervals are important, so let’s list them out:

1b to 2b: 123 years
2b to 3b: 33 years
3b to 4b: 14 years
4b to 5b: 13 years
5b to 6b: 12 years
6b to 7b: 12 or 13 years
7b to 8b: 11 or 10 years

The population growth right now is the lowest it has been since 1950, with less than 1% of growth in 2020, and a UN report estimates we’ll see significantly longer interval between eight billion people and nine billion – almost thirty years. The same report predicts a long population peak in the 2080s of approximately 10.4 billion, and then a potential decline.

Is yesterday literally the day the eight billionth baby was born? No, and there’s no way to assign an actual exact day – there is no global census and it certainly couldn’t be done in real time. But it is important to mark the statistical milestone, all the same, and consider what it means.

Photo: Cmglee / Wikimedia Commons