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Population Growth & Sustainable Development

Author: Dr Eureta Rosenberg

( Article Type: Overview )


In January 2015, Earth's human inhabitants numbered about 7,3 Billion - and counting. Consider these predictions:

  • It is estimated that by the year 2025 the increased number of people on earth will use up 70% of the available fresh water. If consumption increased everywhere to current developed-country levels, we will be using 90% of available fresh water. 
  • A child born today in an industrialised country will consume more and pollute more in his or her lifetime than 30 to 50 children born in a developing country.
  • By the year 2050, an estimated 4.2 billion people will be living in countries that cannot meet the minimum requirement of 50 litres of water a day.


 Human Population Growth - Timeline

The table below illustrates this, including the great acceleration over the past 200 years. It forces us to ask the question: What will happen if the human population continues on its current growth path?



Impacts of Population Growth on Water Resources

Growing populations are faced with the harsh reality of limited natural resources. The issue of water supply is a good example to demonstrate that unrestrained population growth is not sustainable. Consider this:

  1. Water, like other natural resources, is not evenly distributed around the globe. The countries described as 'developed' or 'industrialised' have in general more abundant sources of water, or the technology to use water more efficiently.
  2. The supply of fresh water is essentially fixed. While technical means are being explored to increase the supply of fresh water (such as Desalination) their impact is likely to be limited.
  3. We are already consuming close to the planet's limits. Worldwide, 54% of the annual available fresh water is already being used. This may seem to leave a lot to spare, but scientists have demonstrated that we need to leave a certain volume of water in rivers and other wetlands as an ecological 'reserve', in order to maintain their functional viability. When we use up this reserve, we destroy these ecosystems and reduce the overall available volume of water.
  4. This level of use (54%) is based on unequal consumption: Around the world, some 1.1 billion people do not have access to fresh water, or consume less than the basic daily requirement of 50 litres.
  5. Population growth will also result in greater volumes of pollution. In developing countries, 90-95% of sewage and 70% of industrial waste are dumped into surface waters thus polluting the water supply. Water quality is also affected by chemical run-off from pesticides and fertilisers and acid rain from air pollution, requiring expensive, energy-intensive processes to clean it for human use. 

Water is not only a basic human need, without which we die. It is also the basis of health, food security and economic development. For individual families, lack of access to clean water is associated with unhygienic living conditions, already one of the biggest causes of deaths among infants. On a national and regional level, cash crops and other industries depend on water supplies. As water becomes scarcer, we see not only a decrease in the quality of life, but an increase in social conflict.

The same scenario will play out (and already does) for land and other non-renewable natural resources. These resources limit the number of people the earth can bear sustainably. This is why the rate at which the world population is growing, is such a serious ecological and social threat.


Demographics and trends

Just as the world's natural resources are unequally distributed, the world population is also unequally distributed.


  •  High population numbers are associated with those regions where natural resources are generally more limited. Here the population increase is also the fastest, the consumption per person the lowest, and the negative impacts of growth most acutely felt.
  • Most of the projected growth in the world population will take place in developing countries.
  • By 2050, 85% of the world population will be living in developing countries. (The comparative figure for industrialised countries is 1.6 children per woman.) 
  • The 49 'least-developed' countries will almost triple in size. This level of growth will almost certainly have devastating effects for their environment and inhabitants, with rippling impacts on their neighbours and other countries to which people may migrate.
  • As rural environments become less able to sustain people, an estimated 160 000 rural dwellers move to cities every day. This results in sprawling, densely populated urban areas under great social, economic and environmental stress.



  The Effects of Population Growth

  These include:

  • Social friction (such as crime and xenophobia)
  • health impacts
  • traffic congestion
  • pollution
  • Depletion of city surroundings through concentrated extraction of resources ranging from water to firewood
  • the conversion of farmland or wetlands for housing, roads and shopping centres.


South Africa - Quick Facts

 According to the Statistics South Africa website's Mid-year Populations Estimates 2013:  

  •  In 2013, South Africa's population was estimated at 52.98 million. 
  • Approximately fifty-one per cent (approximately 27,16 million) of the population is female (2013 figure)
  • Life expectancy at birth for 2013 is estimated at 57,7 years for males and 61,4 years for females.
  • The infant mortality rate for 2013 is estimated at 41,7 per 1 000 live births. 



Most agencies involved in population development advocate a multi-faceted and integrated approach. To achieve a sustainable relationship between natural resources, development and human numbers, we need to consider: 

  • Many people still do not get a big enough slice of the cake, as well as the reality that the Earth's cake is of a limited size.
  • Natural resources are essentially fixed and taking strain under the demands of consumption and growing populations.
  • We can produce more food
  • We should distribute resources more fairly and efficiently around the globe.
  • Reducing over-consumption and discarding discriminatory economics can alleviate a great deal of hunger and hardship (see Topic Economic Growth Beyond GDP).
  • Technological advances towards energy-efficient and resource-light production can reduce resource use and pollution, but these steps will not reverse the impact of the population explosion. 

Associated Organisations:

Dikepolana Resources , The Green Times