How is it possible that in just a little over three centuries, we have gone from 680 million inhabitants to 8 billion?
This means that between the year 1700 and 2023, we multiplied by almost twelve.
Isn't this, frankly, madness? What could be the repercussions?
Think about the following data: we completed the first billion inhabitants around the year 1,800.
This means that more than 100,000 years passed (the time we are supposed to have inhabited the planet) before reaching this figure.
From that moment on, the time required to add a new billion to the total population will become increasingly shorter.
The second billion inhabitants was reached in 1927, 127 years later.
Since then, the acceleration of population growth has become dizzying.
We achieved the third billion in 1960 (33 years later), then the fourth billion in 1974 (14 years later), the fifth billion in 1987 (just 13 years later...).
Finally, the sixth billion arrived in 1999 (25 years later), slowing down the growth.
It is expected that by 2050, we will be around 10 billion inhabitants on planet Earth. And this figure is projected to continue increasing to reach 11 billion by the end of the 21st century.
Although we will grow at a slower pace, it is highly likely that the population will not decrease until the 22nd century.
Population growth has been seen favorably by many, since it is considered a synonym of progress.To such an extent that warning voices are already being heard in the face of population decline.
One of the most visible is that of the billionaire Elon Musk who expressed his concern about the population collapse on Twitter (now X).
The underlying question is, will it be possible to maintain food production without (or with less) petroleum?
The energy model of pre-industrial agriculture
Since the agricultural revolution (about 12,000 years ago), humanity has increased its population at an extremely low growth rate, less than 0.4%.
This was partly due to high rates of infant mortality, incurable diseases, unfavorable socio-economic conditions, wars, and famines, which were not uncommon.
Added to this was the fact that food production (one of the fundamental factors for population growth) was limited to physical work that was carried out thanks to the muscular energy of humans and animals.
Plowing, planting, harvesting, and transporting food all required significant amounts of energy (I know from experience...).
What was the energy source that sustained the entire food production system when petroleum was not being extracted?
The answer is simple: the sun.
Since plants, through the process of photosynthesis, transform solar energy into food, this energy flows through the entire food chain until it reaches humans, horses and oxen, which then go out to work in the fields.
However, the energy efficiency of this system was low, because the conversion of solar energy into food requires time and resources.Also, those who did the work needed rest and were frail, and sometimes got sick or died.
The Industrial Revolution and coal transformed agriculture
With the industrial revolution that began in the 18th century, steam engines (produced by burning coal) began to be developed, which increased agricultural production very quickly.
Instead of relying primarily on photosynthesis and solar energy, industrial agriculture began to use non-renewable energy sources to power machinery and industrial processes.
An example of this was the steam mower which quickly became one of the most popular agricultural machines.This allowed hay and wheat to be mowed much faster than manual ways.
The same happened with the thresher, which was used to separate the grain from the chaff;grain elevators, which were used to transport the harvest from the fields to the granaries;and the “new” mills.All powered by steam.
To this was added the train (also powered by steam), which allowed large amounts of food to be moved from one place to another.With which it was possible to distribute food more quickly to a population in constant growth. Farewell to pack animal caravans!
Along with the increased availability of food, we must take into account the effects of improved sanitation, medicines, and economic development.
The results of all of the above are observed in the first and second columns (from left to right) of the graph.
The transition from coal to oil
Although coal represented a significant increase in the amount of farm work that could be done, oil multiplied it vastly more.
Let's put this matter in dimension: while a kilogram of coal has about 30 megajoules (MJ) of energy, a kilogram of oil has about 44 MJ.
This means that oil has almost 47% more energy than coal.
Now imagine the impact this had on the entire food production system.An effect similar to what a bodybuilder experiences when taking steroids to increase muscle mass was generated.
The steroid effect: the injection of oil into agriculture in the 20th century
At the beginning of the 20th century, tractors began to be used in the field, which was possible thanks to the invention of the combustion engine powered by gasoline (derived from petroleum).
The widespread use of this type of motor in a wide variety of field machines made it possible for farmers to perform tasks that otherwise would have been extremely difficult or impossible.
To this we must add the famous "green revolution", which from 1950 began to implement genetic engineering to produce high-yield crops, the use of chemical fertilizers, and improved agricultural management.
Take a moment to look at what happens on the graph with the world population during 1950 when more food becomes available.
Oil also made the global economy grow brutally.So food began to travel through trade routes in trucks, tractor-trailers, ships, and planes.All moved with gasoline or diesel engines, of course.
The result of the above is clearly seen in the graph: an enormous growth that reached the maximum peak in the growth rate during the 1970s, which was 2.1%... (remember that the pre-industrial growth rate wasof less than 0.4%).
The problem is that, although the growth rate has already been declining (and will continue to decline), the mass of population (that is, the number of people) reached during the 20th century will remain undiminished for a long time, not sothe energy that made it possible.
So how will we feed this population?
We have built something untenable, a house of cards that will collapse sooner or later.
The discussion is open
It is clear that oil is a finite resource, so there is no doubt that it will end one day, the question is when.
The International Energy Agency says one thing, governments another, critics of both institutions another, independent analysts another.Who will be right?
There is also the question of whether the energy produced by oil can be replaced by renewables or some other new technology that has not yet been invented.
Other considerations for the analysis of this matter should be:
The speed with which the decrease in oil production would occur.
The effects that climate change will have on agriculture, a more challenging aspect than the same decrease in energy...
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