page_title: Human overpopulation
section_title: Urban growth
hierarchical_section_title: Human overpopulation / Projections of population growth / Urban growth
caption_attribution_description: English: This bubble map shows the global distribution of top 400 "urban areas" with at least 1,000,000 inhabitants in 2006. This map resolves the accessibility issues faced by colour-coded maps that may not be properly rendered in old computer screens. Data was extracted on 27th June 2007 from http://www.citymayors.com/statistics/urban_2006_1.html Based on :Image:BlankMap-World.png Español: Este mapa muestra la distribución de las 400 "áreas urbanas" más pobladas que tenían al menos 1.000.000 de habitantes en 2006. Los datos fueron tomados el 27 de junio de 2007 de http://www.citymayors.com/statistics/urban_2006_1.html Está basado en :Image:BlankMap-World.png
context_page_description: Human overpopulation is when there are too many people for the environment to sustain. In more scientific terms, there is overshoot when the ecological footprint of a human population in a geographical area exceeds that place's carrying capacity, damaging the environment faster than it can be repaired by nature, potentially leading to an ecological and societal collapse. Overpopulation could apply to the population of a specific region, or to world population as a whole.
  Overpopulation can result from an increase in births, a decline in mortality rates, an increase in immigration, or an unsustainable biome and depletion of resources.
  Advocates of population moderation cite issues like exceeding the Earth's carrying capacity, global warming, potential or imminent ecological collapse, impact on quality of life, and risk of mass starvation or even extinction as a basis to argue for population decline.
  A more controversial definition of overpopulation, as advocated by Paul Ehrlich, is a situation where a population is in the process of depleting non-renewable resources.
context_section_description: In 1800 only 3% of the world's population lived in cities. By the 20th century's close, 47% did so. In 1950 there were 83 cities with populations exceeding one million; but by 2007 this had risen to 468 "agglomerations". If the trend continues, the world's urban population will double every 38 years. In 2007 UN forecasted that urban population would rise to three out of five or 60% by 2030 and an increase in urban population from 3.2 billion to nearly 5 billion by 2030. As of 2018 55% live in cities and UN predicts that it will be 68% by 2050.
  The increase will be most dramatic in the poorest and least-urbanised continents, Asia and Africa. Projections indicate that most urban growth over the next 25 years will be in developing countries. One billion people, one-seventh of the world's population, or one-third of urban population, now live in shanty towns, which are seen as "breeding grounds" for social problems such as unemployment, poverty, crime, drug addiction, alcoholism, and other social ills. In many poor countries, slums exhibit high rates of disease due to unsanitary conditions, malnutrition, and lack of basic health care.
  In 2000, there were 18 megacities – conurbations such as Tokyo, Beijing, Guangzhou, Seoul, Karachi, Mexico City, Mumbai, São Paulo, London and New York City – that have populations in excess of 10 million inhabitants. Greater Tokyo already has 38 million, more than the entire population of Canada (at 36.7 million).
  According to the Far Eastern Economic Review, Asia alone will have at least 10 'hypercities' by 2025, that is, cities inhabited by more than 19 million people, including Jakarta (24.9 million people), Dhaka (25 million), Karachi (26.5 million), Shanghai (27 million) and Mumbai (27 million). Lagos has grown from 300,000 in 1950 to an estimated 15 million today, and the Nigerian government estimates that city will have expanded to 25 million residents by 2015. Chinese experts forecast that Chinese cities will contain 800 million people by 2020.
caption: Urban areas with at least one million inhabitants in 2006. 3% of the world's population lived in cities in 1800, rising to 47% at the end of the twentieth century.
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