Which invention in human history has had the greatest impact on our well-being? The computer? The plow? The printing press? Nutella? All undoubtedly worthy candidates that deserve a regular place in the ancestral gallery of mankind’s most important inventions. However, it is another candidate that is repeatedly mentioned in a prominent position by scientists.
This story begins with a blazing appeal to the British Association for the Advancement of Science in Bristol in 1898. Long before the 1972 Club of Rome report ‘The Limits to Growth’, warnings about the limits to growth were common tools for dramatically demonstrating to contemporaries the effects of unchecked growth. The solutions can be summarized in two categories: Either do something about it or do something for it.
In Bristol, British physicist and chemist William Crookes painted a grim picture by contrasting the rapidly increasing population with the food supply. In 20 years, Crookes said, food demand would exceed supply. Crookes therefore saw the most urgent problem of his day as finding an economical way to artificially produce the most important fertilizer ingredient, ammonia. Such warnings were not new. For exactly 100 years earlier, Crooke’s countryman, the economist Thomas Malthus, had first warned of overpopulation in his 1798 ‘Essay on the Principle of Population.’ But now it seemed all the more urgent.
Heeding William Crookes’ call for new solutions, Fritz Haber and Carl Bosch saved us from starvation with ammonia synthesis using the process named after them. Seventy-four years later, the Club of Rome warned of similar problems with its report ‘The Limits to Growth’. Whereas Crookes had been a one-man operation, the Club of Rome commissioned the Massachusetts Institute of Technology (MIT) with a lot of money to conduct data analyses and computer simulations to determine threat scenarios for humanity. The much-discussed and influential report analyzed industrialization, resource exploitation and environmental pollution in addition to the trends of population growth and malnutrition already mentioned by Crookes. The report’s central finding was summed up in one sentence:
If the current increase in world population, industrialization, pollution, food production, and exploitation of natural resources continues unabated, the absolute limits to growth on Earth will be reached within the next hundred years.
Five decades later, there are some surprising findings. Climate change, which was not mentioned in the report – as a result of pollution and industrialization – has come to the fore as a real threat to humanity. Malnutrition and population growth, on the other hand, lost their threat potential. While almost half of all people worldwide were still living in extreme poverty at the time of the report’s publication, the figure was only nine percent in 2017.
Mankind has thus managed to combat and solve threats collectively, thanks to the ingenuity inherent in us humans. Hunger and poverty now affect only a relatively small number of people, and we are well on the way to helping them as well. The current problems warning of climate change and energy shortages are the new scenarios being put forward. Even though we are living in times of a pandemic, we ourselves are amazed at how quickly we have been able to develop vaccines. Technologically, COVID has been defeated, politically and socially not quite yet. But the technical solutions to climate change and possible ones to eliminate our energy bottleneck are also available or on the way to being solved. We have more or less all the technologies at hand to solve climate change, what is missing is the political and social will. Our growing hunger for energy is also on the verge of being solved. Alternative forms of energy are available, nuclear fusion seemingly on the verge of a breakthrough.
But what about population growth? Can we solve that? And above all: is this actually a problem?
The Seattle-based Institute for Health Metrics and Evaluation (IHME) at Washington University predicts an end to population growth sooner than previously thought. Instead of the 10.9 billion people predicted by the UN in 2100, the IHME sees the peak of 9.7 billion as early as 2064. From that point on, the global population is actually expected to decline.

And this is where the real new problem begins: How do we deal with a shrinking world population? As we can see with the aging of the population, in Japan, for example, this leads to stagnation and less dynamic economic activity. The country’s competitiveness and thus its standard of living are declining. China is facing the same problem thanks to its one-child policy, which has turned the age pyramid upside down. And in the German-speaking countries, things are not looking any better, with a delay. Falling birth rates make this a challenge not only here, but worldwide.
Not overpopulation, but an impending population collapse will become the urgent problem. Alibaba founder Jack Ma relates this to China and says that the threat to humanity is not too many people or a superintelligence, but that people simply don’t want any more babies.
Humanity has succeeded in fighting hunger and epidemics over the past decades. Even though we still haven’t lifted everyone out of poverty and every now and then a pandemic hits us, human ingenuity has brought us approaches and technologies that can effectively fight poverty and prevent and cure many contagious diseases. Now, on the list of major problems to be solved, pollution and the associated extinction of species and climate change are at the top of the list. If we do not find a common approach and solutions there, they could reverse the previous successes in the area of poverty and epidemics.
However, there is no reason to believe that these problems are not within the realm of the solvable. Just as with hunger, poverty and disease, concerted action by communities of nations and human ingenuity help. We passed laws and offered incentives, researched vaccines, developed better fertilizer, switched to more sustainable forms of energy. In other words: We have dramatically increased the Earth’s ecological carrying capacity – the number of people it can support without problematic impacts on the environment, for example – several times in human history. If we take into account that today the majority of the world’s population does not live evenly distributed across the globe, but is concentrated in cities, then we are reasonably far from overpopulating the earth.
Proposed solutions are already being eagerly tinkered with. From meat substitutes, renewable energy, plastic-eating bacteria, recyclable materials and processes, production methods such as 3-D printing that produce much less waste, and energy-saving construction methods, to name just a few examples, these are all signs that we will also be able to solve such challenges in this century.
Not everyone will agree with this optimistic statement and I can understand the reasons. But let’s compare the population with the time when William Crookes issued his warning in Bristol. He would be amazed today, a little more than a hundred years later, that the world’s population at that time has grown from 1.7 billion people to almost five times that, with a simultaneous increase in prosperity and a reduction in poverty from 75 percent to 9 percent of the population. Nor would he recognize his country, and that’s mainly because he no longer has to breathe air polluted by chimney soot.
So what do we do from the year 2064? For Germany, the question arises as early as 2035. An international study from July 2020 forecasts a shrinking of the German population from that year, with the highest population of 85 million, to 66 million by 2100. According to current trends, this shrinking means a thinning rural population, fewer workers and rising costs, as well as more facilities to cater to the needs of an aging population. For Manuel Slupina of the Berlin Institute for Population and Development, the effects are already clearly visible in some regions.
This is the case in the south of Brandenburg, in the Uckermark, in the Prignitz, in parts of Saxony-Anhalt, in northern Hesse, in the southwest Palatinate and in northern Bavaria. These are regions that have been experiencing what it means to have fewer people for some time.
There is another reason why we should be more concerned about population collapse than overpopulation. We have always been able to solve the latter challenge, as we discussed earlier, and there is no indication that we will not be able to solve it in the future. In my 2020 book on artificial intelligence, ‘When Monkeys Learn from Monkeys,’ I cite an experience from medical research. Although the number of scientists in medicine doubles every 15 to 20 years, we are not making more progress than before. The progress between 1950 and 2000 is the same as that between 1900 and 1950. The reasons are manifold.
- Scientific progress becomes more and more difficult. Initially, one solves relatively simple problems, but the remaining ones become increasingly difficult and cost more time.
- The more people working on something, the higher the communication effort becomes.
- The more knowledge there is, the more effort has to be invested in training and understanding the knowledge, which makes the scope of knowledge and tasks of a single researcher much narrower.
If we want to maintain the pace of medical progress, we will have no choice but to put more and more intelligence into it. Traditionally, this has been done by putting more people to work. Today, there are more researchers working in science and more people holding PhDs (from whatever field) than there have been in all of human history combined.
We thus need to scale intelligence. And this can be done in several ways, and again in combination. First, train more people and increase their level of training. Create artificial intelligence to expand our intelligence and intelligence space. And take intelligence to the next level through a network of brains, publications, intelligence tools such as computers, formulas, mathematics, programs, algorithms, and otherwise coded knowledge.
This intelligence is not just an isolated brain in a jar, but all these things must be considered in context and interaction with the environment. It is not the individual who will become superintelligent, but our civilization as a whole that will become more intelligent. One person alone can’t build a computer or do space travel, but together as a society we can. Only more available intelligence can help us tackle ever greater challenges of an increasingly complex world.
A shrinking and aging population is taking up important resources. Focusing on a few tasks that ostensibly need to be given higher priority only works to a limited extent. Methods and innovations from so-called peripheral areas or less important ‘orchid subjects’ can provide the decisive approaches to solving fundamental problems in the focus areas.
The threat of population collapse should worry us.
Parts of this post are taken from my August 2021 book Future Angst: Wie wir von den Innovationsvorreitern zu den Innovationsnachzüglern wurden und wie wir die German Angst überwinden.