Population growth as a driving force for environmental problems
| Population growth is known as one of the driving forces behind environmental problems, because the growing population demands more and more (non-renewable) resources for its own application. So why exactly does the human population expand to rapidly? To understand this, we must first explain a little about the difference between linear and exponential growth, in other words, add a little basic math to the equation. |
Growth is usually thought of as a linear process: an increase by a constant amount over a period of time. The new amount is not influenced by the amount already present. For exponential growth, this is different, because the increase of a factor is proportional to what is already there. When cells divide, there will be a constant doubling of the cells already present. In terms of population growth, the numbers of people already present always influences the number of children born in any country. It is however not a simple matter of a constant doubling of the amount. Other factors, such as fertility and mortality rates, influence population growth, and the sexe and age of people already present, and rational decisions influence whether or not people will actually have one or more children.
Schematically, this can be represented as follows:
Population growth = birth rates – death rates
So how rapid does our population grow? Meadows et al. (2004) state that in 1650 the human population counted only 0.5 billion heads. By 1900, the population had increased to 1.6 billion heads and was growing increasingly more rapidly, to 3.3 billion in 1965 (see figure). Not only the population itself was growing, but also the doubling time was decreasing, which basically means that growth itself was growing. This rapid growth increase was mainly caused by a decreasing death rate (more rapidly than birth rate), and particularly an increase in average human age. By 2000 the population counted 6 billion heads, however, population growth (doubling time) started to decline after 1965 because of decreasing birth rates.
The European population is now thought to decline in the future, because of a decreasing average number of children per family. Total world population continues to grow, but less rapidly because of population dynamics in developed countries.
Population growth for specific countries