From Wikipedia, the free encyclopedia
Graph of human population from 10,000 BCE–2000 CE showing the immense population growth, since the 19th century.
Overpopulation is a condition where an organism's numbers exceed the carrying capacity of its habitat. The term often refers to the relationship between the human population and its environment, the Earth.[1] Steve Jones, head of the biology department at University College London, has said, "Humans are 10,000 times more common than we should be, according to the rules of the animal kingdom, and we have agriculture to thank for that. Without farming, the world population would probably have reached half a million by now."[2] The world’s population has significantly increased in the last 50 years, mainly due to medical advancements and substantial increases in agricultural productivity.
The recent rapid increase in human population over the past two centuries has raised concerns that humans are beginning to overpopulate the Earth, and that the planet may not be able to sustain present or larger numbers of inhabitants. The population has been growing continuously since the end of the Black Death, around the year 1400;[3] at the beginning of the 19th century, it had reached roughly 1,000,000,000 (1 billion). Increases in medical technology have led to rapid population growth on a worldwide level. Current projections show a steady decline in the population growth rate, with the population expected to reach between 8 and 10.5 billion between the year 2040[4][5] and 2050.[6]
Map of countries by population density, per square kilometer. (See List of countries by population density.)
Areas of high population densities, calculated in 1994.
Map of countries and territories by fertility rate (See List of countries and territories by fertility rate.)
Human population growth rate in percent, with the variables of births, deaths, immigration, and emigration - 2006
The scientific consensus is that the