This Crash Course video talks about how the longest period of exponential population grown has been from 1650 to present day. The population has tripled in the world since 1650, and now there are more than 7 billion people in the world. The reason why the population has been growing is due to demolishing limiting factors. We have better agriculture, medical advances, expanding the human habitat due to technology advancements, and sewage systems. The amount of people the Earth can hold is due to our ecological footprints. The Earth is a limited space and therefore there is a limited amount of resources for the growing population.