There are a lot of humans on planet Earth - almost eight billion and counting. In fact, humans and the livestock we raise to feed ourselves now comprise about 96% of the global biomass of mammals. Our footprint on planet Earth is literally massive.
Of course, this wasn’t always the case1. 12,000 years ago, only four million of us walked the Earth. 10,000 years later, around the year 0, it had grown to 190 million. Around 1800, the global population surpassed one billion. It took just over a century for the population to double, and in less time than that, the population has nearly quadrupled. Humanity has exploded in the 20th and 21st centuries.
Why did this happen? Well, we slashed each of the three major threats we’ve faced for thousands of years. We’ve become far less violent, ushering in an extended era of peace and safety that has prolonged many lifespans. We’ve emphasized sanitation and curbed the spread of infectious diseases, particularly in wealthier countries, further extending the average lifespan. These two accomplishments have greatly contributed to global prosperity. But they pale in comparison to the key driver of rapid population growth: we’ve gotten much better at feeding ourselves.