How Many People Can Live On Earth?

The earth’s population continues to grow. More than eight billion people have inhabited the planet. But resources are running out. The modern way of life overwhelms nature. How many people can even live on earth? Let’s find out.

Humanity is growing every second. The world population clock is ticking relentlessly. When you have finished reading this sentence, there will be around 50 more people. A total of 8 billion. If the world population continued to grow at the same rate as, in the past three centuries, around 70 billion people would populate the planet by 2300.

Can that even work when the planet is already whistling on its last hole? A group of Scientists calculates the ‘Earth Overload Day’ on which natural resources are consumed by mankind every year that should have been consumed by the end of the year. In 2019 it was July 29th. This year, the deadline has been postponed to August 22nd due to the coronavirus pandemic. Nevertheless, the earth’s carrying capacity, i.e., the maximum number of people who can theoretically live on it indefinitely without harming it in the long term, seems to have already been exceeded.

Which begs the question, ‘how many people can the earth carry?’. It is a very difficult question, on which most of the experts do not agree. There are always uncertainties in estimating future population trends and indeed, the prognoses differ widely. The United Nations (UN) had evaluated 65 studies, the most pessimistic of which assume 2 billion people or less. However, the majority of the studies range between 4 and 16 billion possible people on earth.

A trillion people in cathedral cities?

A very optimistic forecast even assumes around a trillion people. The Italian physicist and systems analyst Cesare Marchetti demonstrated in his 1979 essay ‘1012: A Check on the Earth-Carrying Capacity for Man’, that people could use the available energy resource much more efficiently in the future. All people could also live in gigantic ‘cathedral cities’ that only cover a tenth of the earth’s surface. The gist is that the right technology can enable a sustainable existence.

A little optimism does not seem inappropriate, after all, critical researchers in the past were often completely wrong with their warnings of a population explosion. The British economist Thomas Malthus, in the early 19th century as well as the Club of Rome in the 1970s, predicted that the earth’s collapse was imminent amidst the dwindling resources and steady population growth.

But it turned out differently. The collapse did not materialize, the earth was ultimately able to carry significantly more people than contemporaries thought. Above all though technological progress, for example in agriculture, the limit of the earth’s carrying capacity has been shifted again and again since Malthus. A major example of this type of development is the Green Revolution that took place in the late 1960s. With it, significantly higher-yielding crops such as wheat, maize, and rice were introduced worldwide, enabling more people to be fed from the same agricultural area.

One earth is currently not enough

However, technical progress does not mean that it is sustainable. Because the Green Revolution also had some disadvantages. For example, in some regions, the groundwater level is falling due to greater water consumption. Intensive agriculture also involves the heavy use of fertilizers and pesticides. In order to supply the present world population in a truly sustainable way, 1.6 earths would still be necessary. If all people on earth lived as they live in developed countries, it would be almost 3 earths.

So can mankind today even live sustainably on earth? A study from 2018 calculated that more than 7 billion people could live on the planet permanently and sustainably. However, it is not the existence we are used to. Rather, it would be limited to basic needs such as nutrition, health care, electricity, and the eradication of extreme poverty.

Almost 8 billion people now live on earth. And with the population still growing rapidly in sub-Saharan Africa and parts of Western Asia, the number is likely to rise significantly. However, the increase should slow down in the coming decades. The UN is therefore expecting growth to almost 11 billion people in 2100. In a worst-case scenario, however, it could be 17.6 billion people.

This has to do with development progress in countries like India, Nigeria, Pakistan, Ethiopia, and Tanzania, which are leading to falling birth rates. One then speaks of the demographic transition, such as the industrialized countries in Europe, North America, and East Asia have already seen. The birth rate there is currently lower than anywhere else in the world, which is already leading to a decline in the population, like in Japan.

Finding a middle ground

However, this results in a dilemma as advances in previously underdeveloped countries go hand in hand with increased resource consumption, which in turn reduces the earth’s carrying capacity. One possible way out is that the people in the industrialized countries would have to change their consumption behavior and reduce the global consumption of resources. This would create space for less developed countries. In the end, there could be a kind of global standardization of living at a level below that of today’s industrialized countries and above that of poorly developed countries.

At the same time, the poorly developed countries should avoid the mistakes of the industrial nations and make major leaps in development much faster, cheaper, and more sustainably.

This is quite possible as there are already many positive examples in Africa of how the productivity in agriculture can be increased in a sustainable manner and education is spread across the board so that as many people as possible have access to it.

Also Read – For How Long Will The Earth Sustain Life?

But what if the stagnating population in developed countries begins to grow significantly again in the future? For example, the massive use of robots could relieve people of so much work that having children could not only become easier but also a new purpose in life. The birth rate would then rise again noticeably. Advances in medicine could also enable people to live significantly older than they are today, which should also lower the death rate. The uncertainty of the population development and its consequences is thus the only thing that seems certain for the time being.