Some blame overpopulation for many of the world’s problems such as poverty, famine and war (which are obviously rights violations). There are supposed to be too many people for peaceful coexistence and sustainable food production. The areas of the world which are inhabitable and useable for agriculture are too small compared to the number of people living in them. These people are followers of Thomas Malthus or of malthusianism, and often even predict major catastrophes which will reduce the population significantly. They also advocate some quite draconian measures for limiting the human population.
In scientific terms: overpopulation occurs when an organism’s numbers exceed the carrying capacity of its habitat; carrying capacity = [available sustainable resources > current and projected needs of the organism].
For example, imagine a population of 10 living in a habitat of 10 square kilometers. These 10 square kilometers can produce food, drinking water, shelter etc. for 15. Then there is no overpopulation. But if the population grows or is expected to grow at a rate of 10% annually, without an equal or superior growth in resources, then overpopulation threatens. There would also be overpopulation if the material resources are adequate but other needs such as space, privacy etc. are not met. For example if the available space is too small to guarantee peaceful co-existence.
So overpopulation can result from changes in the population (increased births, reduced deaths, better healthcare, migration etc.) or from changes in the resources – material or psychological – in the habitat (for example desertification, natural disasters, technological innovations etc.), or from a combination of both.
The current state of the world’s population is the following:
- Present world population – 6,500,000,000 but unequal distribution of world population (see graphs below). The main population clusters are East Asia, South Asia, Southeast Asia and Europe.
- Average world growth rate – 1.4% annual, but also unequal distribution of growth rates: fastest growing areas are the Middle East – over 4.0% annual – and the slowest growing areas are Central and Eastern Europe – 0% or less. Southern Africa even sees negative growth rates as a result of the HIV epidemic.
- Forecasts are notoriously difficult but the world’s population is expected to rise by 40% to 9.1 billion by 2050.
Blaming everything on overpopulation is misguided and reductionist. Problems such as poverty and war have a complex set of causes, including in some but not all cases overpopulation, government policies, cultural factors, repercussions from colonialism, religion etc.
One can also question whether there is indeed a problem of overpopulation. Per capita food production has risen the last 50 years, and poverty (expressed as the number of people living on less than 1$ a day) has decreased while the population has increased. So poverty and war may not have anything to do with the size of the world’s population. However, ecological problems may have something to do with it. If so, the solution would surely not be population control, which is much too difficult and often dictatorial. Changes in consumption patterns are a much more promising route.