How many people can the earth support?

　　In 2022, the United Nations announced that the total global population will officially reach 8 billion!
　　The development of science and technology and civilization has brought safety and hygiene to human beings, and the number of human beings has skyrocketed on the earth. Even if young people in many countries around the world choose to stay away from marriage, they still cannot stop the trend of population growth. However, the size of the earth will not increase with the population. Will the limited earth not be able to support the almost “infinite growth” of human beings? How many people can the earth support?
　　If other needs are not considered, let the existing 8 billion people on the earth line up in a square array with a distance of one meter, and the total area will only be 256,000 square kilometers. But if you take into account the arable land, water source and raw material production required to feed one person, each person needs about 2.1 hectares of land. But this is only the world average. If everyone lives in the American way, then each person will need 10 hectares of land. It seems that only when all human beings are vegetarians can the number of people that can be supported per unit of land be increased.
　　Considering that 38% of the earth’s land area (about 5 billion hectares) has been used for the production of human food and raw materials, we are not far from the limit of the earth’s carrying capacity. So, can we increase the yield per unit land area to increase food income? Like hybrid rice…
　　that’s for sure. However, scientists believe that the increase in land output efficiency is linear, while the population grows exponentially, and one day there will be not enough food to eat. This theory is undoubtedly correct in the long run. For example, the current global average growth rate of agricultural efficiency is already lower than the population growth rate.
　　Joe Cohen, a famous demography researcher at Rockefeller University in the United States, once collected the predictions made by 65 top research institutions around the world and found that most institutions believe that the earth can only support 8 billion people at most, and another 14 institutions put this figure Raised to 16 billion. But none of these projections take into account improvements in quality of life, otherwise the figure would surely be lower.
　　Obviously, the current number of humans has reached the limit of the number of humans that the earth can support as predicted by most research institutions! what to do? Will the number of humans continue to skyrocket?
　　1992 is considered the first year of the modern environmental movement, and the total population of the planet in that year was about 5.5 billion. Therefore, experts estimate that if the fertility rate remains at the level of 1992, the total population of the earth will double to 11 billion by 2025; the total population of the earth will reach 46 billion by 2076. The population growth rate must be suppressed, otherwise when the earth is no longer enough to feed all human beings, we will only face wars and plagues.
　　Fortunately, at present, with the continuous improvement of modernization and women’s education level, the global average fertility rate is declining year by year. The latest forecast is that the earth’s population will reach a peak of 10 billion by the end of this century.