*3.2. Population*

It is beyond dispute that population growth is among the main drivers of global changes (notice in Figure 1). In approximately 10,000 B.C., agriculture began to develop with a global population of approximately 2.4 million people [23]. At the beginning of our chronology, Earth's population was

188 million. As a result of the industrial revolution and the parallel development of health care and medicine, a major change occurred. By the end of the 1800s, the global population reached or already exceeded one billion people [24]. Currently, China alone has a population of 1.4 billion people [25]. The next major period was the 1930s when global population exceeded 2 billion people (when maize hybrids began to spread) (Figure 1). Due to the achievements of the Green Revolution, the global population doubled to over 3 billion (1960). It has been established that the global population grew from 1.65 billion to 6 billion during the 20th century. In 1970, there were nearly half as many people in the world as today [26]. By the middle of the 20th century, annual global population growth rose to 2.1% (1962), which is the highest annual growth rate in history. Nowadays, the growth rate has fallen to 1.2%, which is less than 80 million people annually. According to forecasts, the annual growth rate will decline to 0.1% by 2100 [27].

**Figure 1.** Global population growth. (Source: Own calculation and editing based on the database of FAO, 2019) [13].

Population growth in itself does not completely explain the changes in food consumption. While the volume of food consumption is dependent on the size of the population, quality of the consumed food is dependent on the average household income. According to Figure 2, there is no apparent connection between the (log of the) population and the (log of) GDP per capita, which means that independently from the population of the given countries, the GDP per capita may vary freely. At the same time, a higher GDP is more likely to be associated with a low share of agricultural added value. At the bottom of the graph, African countries possess a very high agricultural share in the GDP, while Europe at the top of the graph is very much the opposite with a high GDP per capita and a low share of agriculture (Figure 2).

**Figure 2.** The connection among the population—GDP per capita and agriculture, 2017a. (Source: Own calculation and editing based on the database of the World Bank, 2019) [12].

Figure 3 shows the connection between the share of agriculture (as value added in % of GDP) and the GDP per capita. GDP per capita is measured in current US\$, plotted in logarithmic form. As the GDP per capita increases in a given country of the world, the share of agriculture decreases quickly. Generally, African countries (red color) have the highest share of agriculture in GDP among the regions, with over 30% or even more in some cases. However, at the same time, the value of GDP per capita is very moderate. Asian and African countries have a relatively low GDP per capita but high share of agriculture in GDP. The values of Asian countries are extremely diverse. At the same time, European and North American countries typically have a high GDP per capita, while the share of agriculture is only a few percent. The share of agriculture is much lower in Latin America, Oceania, Northern America and especially in Europe, mostly under 5% of the GDP. At the same time, GDP per capita is the highest among the countries. The graph indicates that African and Asian countries are still very much dependent on agriculture, as they take a high share of the GDP (denoted by red and orange).

In Figure 4, a similar methodology-based editing can be noticed. It deals with the connections between energy consumption, agriculture and the GDP per capita. With these elements, the latest database is from 2013. It also indicates the regions with different colors and the GDP per capita value in US dollars. The "X" axis represents the energy usage (in kg of oil equivalent per capita) and the "Y" axis represents the share of agriculture in the GDP. It can be read that energy use per capita is very low in the case of Africa—the value is well under 2500 kg of oil equivalent per capita. A correlation also can be discovered between the agricultural share in the GDP and energy usage. In regions, where the share of agriculture in GDP is high (over 20%), there is a low value energy use per capita (under 2500 kg of oil equivalent per capita). In general, as a country became more industrialized, energy demand increased rapidly and, at the same time, the share of agriculture in the GDP quickly took a downturn. It can be concluded that countries with a high consumption of energy have much higher living standards in terms of the GDP per capita compared to countries with low energy consumption.

It is also worth noticing that the relationship is not linear. Below the 2500 kg of oil equivalent per capita consumption, a small increase in the energy use comes with a rapid decrease in agricultural share in the GDP. Above this level, no further change is expected. According to the regional distribution, Africa shows a lower level of energy consumption and the share of Asia varies between the lowest levels and the highest levels of oil consumption.

**Figure 3.** The relationship between GDP per capita and the share of agriculture in GDP, 2016. (Source: Own calculation and editing based on the database of the World Bank, 2019) [12].

**Figure 4.** The main connections between energy consumption, agriculture and the GDP per capita, 2013. (Source: Own calculation and editing based on the database of the World Bank, 2019) [12].
