In the year 1800, there were just 913 million people in the world. By 2050, there could be more than 9.5 billion, meaning the global population will have grown 10-fold in 250 years. Our planet is becoming ever more full of people, with all the implications you can think of for food resources, climate change, and energy supplies.
Take a look at this interactive map prepared by Population Connection, a Washington, D.C., nonprofit. It shows a timeline of population from 1 CE to the middle of this century. Yellow dots indicate every 1 million people, while the color-coded lines at the bottom show milestones for food and agriculture (red), health (blue), olive (people and security), brown (environment) and green (science and technology). Scroll over the timeline for any of the colors and you see things like "smallpox in the Americas" in the 1500s.
Meanwhile, you can "overlay" different data using the dropdown in the top left-hand corner. These include urbanization, CO2 emissions, life expectancy, and fertility rates. Urbanization is interesting. If you toggle over the map with that overlay, you can see city-dwelling rates for that country. In 1756, Nigeria had a urbanization of 17.1%, for instance, compared to 70.4% in the United States.
Population Connection has been mapping population growth for 40 years. The latest edition came out last year and is available in several languages. It also produces this population number chart, where you can plug in your birthdate and see where you come in the stream of humanity. I'm in the 4 millions somewhere.