Ecosystems

Biodiversity is the range of different species present in the community of an ecosystem. The biodiversity of ecosystems can be affected by population growth, human activities and natural hazards.

Impact of the increasing human population

Like all living organisms, humans exploit their surroundings for resources. Before the beginning of agriculture about 10,000 years ago, small groups of humans wandered across large areas, hunting and gathering just enough food to stay alive. Population numbers were kept low because of the difficulty of finding food.

Population growth

The development of agriculture led to a population explosion that has accelerated enormously during the past 500 years. Unlike other species, humans can adapt to and survive in almost all terrestrial environments on the planet.

Human population growth over the past 10,000 years:

A graph showing the population growth over the last 10,000 years. The y axis is population in billions, it goes from 0 - 6. The x axis is date from 8000 BCE to 2000 CE. Until 2000CD the plotted line rises slowly, but never goes above 0.5 billion.  At this point it rises almost vertically off the top of the graph.

The graph shows that the human population is increasing every year. This is because the number of births each year is much greater than the number of deaths.

In the last 50 years the population of humans on the planet has increased from 3 billion to 7 billion people. This increase is more rapid than at any other point in the history of our species.

The human population is predicted to reach around 10 billion by 2050. As the population increases, the yield of food from farming will also have to increase or malnutrition and starvation will occur.

The yield of crop plants per unit area of farmed land can be increased by intensive farming methods, such as the application of chemical fertilisers and the widespread use of pesticides. These methods have the advantage of increasing the quantity of food that can be produced, but can also have an adverse effect on the environment.

Ecological footprint

This is the area of the Earth that is needed to provide the resources a person requires and to remove their waste products. A person’s ecological footprint is a measure of their impact on the environment.

The average ecological footprint of each human is currently 2.3 hectares of land. This area is bigger than 3 football pitches. According to the World Commission on Environment and Development there are only 1.7 hectares of productive land available to every human. This means many people are not living in a sustainable way.

This map shows the ecological footprint of different countries.

Map showing the ecological footprints of different countries. The highest are some of the arab nations, North America, Australia and Western Europe.

For humans to live in a sustainable way either the world population must be smaller or each person should make a smaller demand on the environment.