|MadSci Network: Environment/Ecology|
It's actually difficult to know exactly how many people live in the world, because in many countries, communication and transportation systems are so poor that no one can make an accurate count. The best estimates we have for current population size are about 5.9-6 billion people. Most of those people (more than 3 billion) live in China and India. About 260 million live in the U.S.
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