Why do many people accelerate


Population in absolute numbers and growth rate per year in percent, worldwide 1950 to 2060

Source: UN - DESA, Population Division (2015): World Population Prospects: The 2015 Revision
License: cc by-nc-nd / 3.0 / de /

For most of human history, the population has changed slowly - just 500 years ago there were only 500 million people in the world. Massive population growth only started in the middle of the 17th century. In 1800 there were already one billion people in the world and a good 200 years later there were seven billion. Even if growth has slowed somewhat, the world population is currently increasing by around 83 million people every year. According to UN calculations, the population will be between 8.7 and 10.8 billion in 2050. If a longer period of time is considered, the different assumptions about the frequency of births have an ever greater effect: A mathematical difference of one child per woman leads to a population of between 7.3 and 16.6 billion by the year 2100.


An estimated 300 million people lived in the world 2,000 years ago - fewer than today in the 19 countries of the euro area. While the population largely stagnated in the following 1,000 years and only increased moderately to 500 million between the years 1000 and 1500, population growth accelerated sharply from around the middle of the 17th century. Around 1800 there were around one billion people in the world, a hundred years later it was 1.65 billion and in 1950 it was 2.52 billion. More than 6 billion people have lived in the world since 1999 and more than 7 billion since 2011 (2015: 7.35 billion). The population projections of the Department of Economic and Social Affairs (UN / DESA) range from 8.7 to 10.8 billion people for the year 2050. According to the medium variant, the population in 2050 will be 9.73 billion.

Especially with regard to global resources, the population development is of great interest, since population growth coupled with economic market integration or with the spread of consumption-intensive lifestyles means an accelerated reduction in natural occurrences. When the "limit of growth" is reached has often been incorrectly dated in the past. But there is no doubt about the finiteness of many resources that are indispensable for the existing forms of society. The population development is one of the factors that determine how quickly humanity approaches natural limits.

The highest average annual population growth occurred between 1985 and 1990. During this period the population increased by 91.4 million annually. Although the growth rates were higher in the period 1960 to 1975, the absolute increases were lower because the population level as a whole was even lower. The world population is currently increasing by around 83 million people each year. For comparison: In 2015, around 82 million people lived in Germany.

According to the UN / DESA population projections (middle variant), population growth will indeed slow down significantly, but not reverse even by the year 2100. Only with the low variant of the population projections does the number of people decrease around the year 2055. However, even with this variant, the world population - with overall falling growth rates - would initially increase to a good 8.7 billion.

The absolute increase in population also has an impact on population density. In 1950 the population density was an average of 19.4 people per square kilometer, in 1990 the population density was already more than twice as high (40.8). In 2015 there were 56.5 people per square kilometer; in 2050, according to the middle variant of the UN / DESA's population projections, there will be 74.8 people per square kilometer.

The middle variant of the UN / DESA population projections is based on the assumption that the global birth rate will increase from 2.51 children per woman (2010-2015) to 2.25 or 1.99 children per woman (2045-2050 or 2095- 2100) falls. An arithmetical deviation in the fertility rate of around 0.5 upwards (high variant) increases the global population by 1.1 billion in 2050 and 5.4 billion in 2100. A deviation of around 0.5 downwards (low Variant) reduces the population - again compared to the middle variant - by a billion in 2050 or by 3.9 billion in 2100. In the period from 1950 to 1955, the birth rate worldwide was still five children per woman (4.96 ).

Data Source

United Nations - Department of Economic and Social Affairs, Population Division (2015): World Population Prospects: The 2015 Revision

Terms, methodological notes or reading aids

The Population projections by the UN / DESA depend largely on the global birth rate. In this context, the UN / DESA theoretically uses the total fertility rate (TFR) as a basis, but the differences between the data in the individual countries are considerable.

The total fertility rate indicates how many children a woman would have in the course of her life if her birth behavior were the same as that of all women between 15 and 45 or 49 years in the respective year. How many children a woman cohort actually had, on average, can only be determined when the women are at the end of childbearing age (which is currently defined as 49 in Germany, for example). notes to the calculation the total birth rate is available here ...

Unless otherwise stated, the information given here relates to the middle variant of the UN / DESA population projections.

Detailed information on Data basis of the UN / DESA get here ...