The world’s population is projected to hit at least 10 billion by the end of this century. A new video and interactive timeline produced by Population Connection, a nonprofit that advocates family planning programs, shows how scientific discoveries and inventions allowed civilizations to spread across the globe for the last 2,000 years. But the project, timed for World Population Day on July 11, also illustrates the strain that burgeoning numbers put on Earth’s limited resources.
The timeline uses a world map to pinpoint where humans have settled since 1 A.D. A sequence of yellow dots—each representing 1 million people—slowly pops up across the continents as a counter tracks historical eras from China’s Han Dynasty (first and second centuries A.D.) to the information age. White dots indicate a major scientific discovery, environmental event or medical breakthrough that affected the rate of population growth. After the industrial revolution (early 19th century), the dots multiply like a Fourth of July fireworks display, demonstrating how rapidly the global population has increased in just two centuries.
Scientific advances, from the quotidian to the profound, made this human proliferation possible. Before 500 A.D., Chinese engineers designed harnesses for plow animals that improved agricultural production, and drilled oil wells that provided fuel for heating and cooking. The magnetic compass, which came into widespread use after 1300, led to the Age of Discovery and colonial expansion. Flush toilets, invented in 1775, reduced water-borne diseases. Nitrogen-based fertilizer, developed in 1913, helped crops yield more food. Without fertilizer, population analyst Vaclav Smil estimates, two billion fewer people would be alive today.
But there is a downside: research suggests that the population rate won’t slow any time soon, and will squeeze the world’s finite supply of fresh water, arable land and other essential resources. Until people get that proposed colony on Mars up and running, humans will have to do better at living on this planet.