How did we get to 7 billion people so fast?

I was born into a world with about 2.5 billion people, but there are now over 7 billion.

Better medicine and improved agriculture have resulted in longer life expectancies and a dramatic increase in world population. As higher standards of living and better health care reach more parts of the world and bring birth control, population growth should slow, but U.N. forecasters still predict a world peak of over 10 billion by 2100. As population then declines, there will be significantly fewer working people to support the elderly, and that poses an economic dilemma for future generations.

NPR’s video, 7 Billion: How Did We Get So Big So Fast? uses colored liquids to visualize population growth on different continents. WATCH BELOW