What makes overpopulation a threat?

Overpopulation is an undesirable condition where the number of the existing human population exceeds the actual carrying capacity of Earth. Overpopulation is caused by a number of factors. Reduced mortality rate, better medical facilities, depletion of precious resources are few of the causes which result in overpopulation. It is possible for a sparsely populated area to become densely populated if it is not able to sustain life.

Growing advances in technology with each coming year has affected humanity in many ways. One of these has been the ability to save lives and create a better medical treatment for all. A direct result of this has been the increased lifespan and the growth of the population.

In the past fifty years or so, the growth of the population has boomed and has turned into overpopulation. In the history of our species, the birth and death rates have always been able to balance each other and maintain a population growth rate that is sustainable.

As the number of people increases, so does the demand for food, water and other resources. Techniques developed to farm food and produce items that people want to use, from clothes and cars to computers, mean that the Earth’s resources are rapidly being used up. The harmful emissions produced by factories and vehicles cause environmental damage, such as climate change.

In a particular place, over population can also be caused by an influx of people forced into the area due to war, famine or other disasters making their previous home uninhabitable. Climate Change is causing an increase in the number of hurricanes and floods and is likely to cause many more people to become displaced in the future.  Overcrowding leads to further demand for limited resources and this, in turn, can lead to more conflict and warfare.

As humans seek out more resources, they take over land that was once the habitat of other species leading to huge biodiversity loss. Present extinction rates may be as high as 140,000 species lost every year due to humans over fishing and taking over large areas of land (such as tropical rainforests) to use for farming food and fuel crops.

Sir David Attenborough has stated that the level of human population has a knock-on effect on all other environmental problems. In 2013, he called humanity "a plague on the Earth" and suggested that limiting population growth would be necessary to control it.