Many people have already tried to do this calculation, but there is still no definitive answer. Since the pioneer Anton von Leeuwenhoek predicted in 1679 that our planet could support 13.4 billion people, estimates have varied between 1 billion and 1 trillion people! “However, two-thirds of predictions are between 4 and 16 billion people. It seems like a reliable interval to establish a limit, considering that the globe has different patterns of occupation”, says geographer Álvaro Luiz Heidrich, from the Federal University of Rio Grande do Sul (UFRGS). The fact is that the Earth’s population has grown more than 40 times since the beginning of the Christian era. In year 1, it is estimated that there were about 150 million people on the planet. That number doubled in 1350, quadrupled in 1700, and reached the first billion in 1804.
The big leap happened in the 20th century, when urbanization and advances in medicine made the population jump from 1.6 billion to 6.2 billion people. “And this taking into account the great epidemics and wars, which are the most important factors capable of stopping the population increase”, says Álvaro. In the 20th century, growth has only slowed down in the last four decades, with the drop in the birth rate – since 1965, the average number of children per woman has dropped from 4.9 to 2.7. Even so, each year the world receives 77 million more people, 97% of them in underdeveloped countries. The total number of inhabitants that still fit on the planet depends on a combination of limiting factors: the amount of food that man can produce, the standard of living that humanity can achieve and a preservation of the environment that can guarantee life on Earth. . According to the United Nations (UN), it is most likely that in 2050 we will have 9.3 billion people on the planet.
Planet has regions with human anthills and almost uninhabited areas
GUARDED ENTRY
Every year, 1 million immigrants arrive in the United States. In theory, the country supports even more, because it is developed and has only 29 inhabitants per km2. But the threat of terrorism and constant tension between immigrants and natives make America’s borders the most heavily guarded on the planet.
BRAZILIAN DILEMA
With 17 inhabitants per km2, Brazil is a candidate to receive more people, especially in the North. But there are two obstacles: social inequality and environmental risk. The country has 27% of the possible arable land in the world, but if they are occupied, it will be the end of the Amazon
UNAVAILABLE OCCUPATION
Polar areas, deserts and steep mountains occupy a third of the Earth, but are almost uninhabitable. In icy areas, energy costs prevent occupancy. Antarctica, with 8.9% of the surface land on the planet, has only 4,000 inhabitants
EUROPEAN SHRINKAGE
With low birth rates, the European population is aging and by 2050 is expected to lose 124 million people. The continent is one of the most populated in the world (Belgium and the Netherlands have more than 300 inhabitants per km2), but it can still receive immigrants in the western, more developed part
HUMAN MOUNTAIN
Southeast Asia and East Asia make up the so-called “human anthill”. Together, the populations of China, India, Indonesia, Bangladesh and Pakistan occupy only 11% of the surface land on the planet, but account for more than 40% of humanity. Almost half of the new inhabitants of the world are born in this region
OVERPOPULATION IN SIGHT
North Africa concentrates most of the 125 million people worldwide who migrate to other countries each year. In the so-called Black Africa, below the Sahara desert, the problem is the high birth rate. Even with the AIDS epidemic, which has cut off 15 years of life expectancy in the last two decades, the continent is expected to gain another 1.2 billion people by 2050
CLOSED DOORS
Knowing that Australia has only 2.4 people for every km2, you can imagine that there would be a good place to fit more people. Not quite: nine out of ten inhabitants live in cities on the east coast because 66% of the country’s territory is desert. Australia has 5 million foreigners (25% of the population), but has limited the number of immigrants because of the economic crisis
Hunger and environmental devastation also hold back population growth.
POORLY DISTRIBUTED FOOD
In 1798, English economist Thomas Malthus predicted that population growth would be limited by low food production. So far, he has been wrong: by UN calculations, there is already food for 12 billion people. Even so, 830 million suffer from hunger (95% in underdeveloped countries), victims of inequality, poor production in some areas and poor distribution of food
WORLD BLACKOUT
The amount of wealth produced on the planet has increased eight times in the last 50 years. But, as the cake is concentrated in countries with high consumption power, the rest of the world loses out. If humanity spent energy like the Americans, for example, Earth would not support more than 1.2 billion people. If the energy standard were Chinese, the planet could host almost 10 times more inhabitants
DEADLY POLLUTION
No one doubts that environmental degradation can impede population growth and life on Earth. Some examples: since the 18th century, the concentration of carbon dioxide in the atmosphere has increased by 30%. Every year, 200,000 km2 of arable land becomes useless and 120,000 km2 of forests disappear. The effects of these aggressions on the future of the planet are unpredictable.