50 years ago there was only 2.5 billion on earth. Since that time, the population have greatly increase. According the the Internation Program Venter, U.S Bureau of the Census the total population of the world is 6,261,732,108. That 80 million people each year. Overpopulation can cause starvation in parts of the world, cutting down trees, endangering animals, and start war with other countries.