How Many People can Earth Hold?

Thomas Malthus, a philosopher in the late 18th century, wrote this in his article: “The burden of population has far exceeded the carrying capacity of the Earth. Sooner or later, the Earth will be overwhelmed and will bring destruction to mankind.” Malthus believes that eventually we will exhaust all our resources and starve to death in the midst of a massive famine.

So, what is the bearing capacity of the Earth? When will the ever-increasing population challenge the bottom line of the Earth? Is Malthus's famine theory correct?

Many scientists, such as the social scientist Edward O. Wilson of Harvard University, believes that the maximum carrying capacity of the Earth is about 9 billion to 10 billion people.

Wilson wrote in his book: “If all grains are used to feed humans instead of livestock, and everyone is willing to become vegetarians, the current 1.4 billion hectares of arable land can feed about 10 billion people. But in fact, the 1.4 billion hectares of arable land can only feed 2.5 billion people. This is because a considerable number of people are not willing to eat only vegetarian food. Therefore, Wilson believes that from a food perspective, the number of people the planet can feed cannot reach 10 billion.

Other environmental factors that limit the carrying capacity of the Earth include the nitrogen cycle, the available quantity of phosphorus, and the carbon concentration in the atmosphere. However, one of the biggest influencing factors that cannot be considered is the fact that no one knows when the Earth’s population will reach its maximum value, and how much this maximum value will be.

Of course, we may not starve to death at all. According to the demographic projections of the United Nations, the world population will reach 7 billion around 10.31, then 9 billion in 2050, and 10 billion in 2100. However, some scientists also pointed out that the population of people may reach an inflection point and then decrease.

Although the global population continues to grow, the fertility rate of most countries and the planet has gradually declined since 1950. Calculations show that if an average woman produces 2.1 offspring, the total global population will no longer increase. By the end of this century, if the fertility rate can drop to this level, then the global population will stabilize between 9 billion and 10 billion: the Earth happens to be able to hold the population and it is almost overloaded.