United Nations Department of Economic and Social Affairs in the context of "Human population projections"

This is a list of urban areas in the European Union with over 500,000 inhabitants as of 2022. The data comes from Demographia and the United Nations Department of Economic and Social Affairs. Demographia provides figures for urban areas (including conurbations), while the UN DESA figures are a mix agglomerations, cities proper and metropolitan areas. For comparison, Function Urban Area (FUA) population figures by Eurostat are also provided, however, these measure the wider metropolitan areas.

A megacity is a very large city, typically with a population of more than 10 million people. The United Nations Department of Economic and Social Affairs (UN DESA) in its "World Urbanization Prospects" report defines megacities as urban agglomerations with over 10 million inhabitants. A University of Bonn report holds that they are "usually defined as metropolitan areas with a total population of 10 million or more people". Elsewhere in other sources, from five to eight million is considered the minimum threshold, along with a population density of at least 2,000 per square kilometre. The terms conurbation, metropolis, and metroplex are also applied to the latter.

The total number of megacities in the world varies between different sources and their publication dates. The world had 32 according to EU Global Human Settlement Layer (in 2024), 33 according to UN DESA (in 2025), 39 according to the OECD, 42 according to Demographia (in 2025), and 45 according to CityPopulation.de (in 2023). The later two add 13 additional cities that are calculated outside the range otherwise. In total, at most 53 unique places are mentioned as megacities across these sources, although some of these are just agglomerated differently between them. A good percentage of these urban agglomerations are in China and India. The other three-to-five countries with more than one megacity are Brazil, Indonesia, Japan, Pakistan, and the United States. African megacities are present in Angola, Democratic Republic of the Congo, Egypt, Nigeria and South Africa; European megacities are present in France, Germany, Russia, the United Kingdom, and Turkey (also in Asia); megacities can be found in Latin America in the countries of Brazil, Mexico, Colombia, Peru, and Argentina.

The United Nations Statistics Division (UNSD), formerly the United Nations Statistical Office, serves under the United Nations Department of Economic and Social Affairs (DESA) as the central mechanism within the Secretariat of the United Nations to supply the statistical needs and coordinating activities of the global statistical system. The Division is overseen by the United Nations Statistical Commission, established in 1947, as the apex entity of the global statistical system and highest decision making body for coordinating international statistical activities. It brings together the Chief Statisticians from member states from around the world.

The Division compiles and disseminates global statistical information, develops standards and norms for statistical activities, and supports countries' efforts to strengthen their national statistical systems.

This article lists current estimates of the world population in history. In summary, estimates for the progression of world population since the Late Middle Ages are in the following ranges:

Estimates for pre-modern times are necessarily fraught with great uncertainties, and few of the published estimates have confidence intervals; in the absence of a straightforward means to assess the error of such estimates, a rough idea of expert consensus can be gained by comparing the values given in independent publications. Population estimates cannot be considered accurate to more than two decimal digits; for example, the world population for the year 2012 was estimated at 7.02, 7.06, and 7.08 billion by the United States Census Bureau, the Population Reference Bureau, and the United Nations Department of Economic and Social Affairs, respectively, corresponding to a spread of estimates of the order of 0.8%.

The United Nations Conference on Sustainable Development (UNCSD), also known as Rio 2012, Rio+20 (Portuguese pronunciation: [ˈʁi.u ˈmajʒ ˈvĩtʃi]), or Earth Summit 2012 was the third international conference on sustainable development aimed at reconciling the economic and environmental goals of the global community. Hosted by Brazil in Rio de Janeiro from 13 to 22 June 2012, Rio+20 was a 20-year follow-up to the 1992 United Nations Conference on Environment and Development (UNCED) held in the same city, and the 10th anniversary of the 2002 World Summit on Sustainable Development (WSSD) in Johannesburg.

The ten-day mega-summit, which culminated in a three-day high-level UN conference, was organized by the United Nations Department of Economic and Social Affairs and included participation from 192 UN member states – including 57 head of state and 31 head of government, private sector companies, NGOs and other groups. The decision to hold the conference was made by UN General Assembly Resolution A/RES/64/236 on 24 December 2009. It was intended to be a high-level conference, including heads of state and government or other representatives and resulting in a focused political document designed to shape global environmental policy.

The United Nations World Population Prospects (WPP) is the official series of global population estimates and projections produced by the Population Division of United Nations Department of Economic and Social Affairs (UNDESA). Each new revision presents updated data on population size by country and region, covering past estimates (from 1950 onward) and future forecasts (typically through 2100). For example, the 2024 Revision – the 28th edition since the first 1951 projection – reports annual population counts up to 2023 for 237 countries and territories, drawing on over 1,900 national censuses (1950–2023) and thousands of surveys, and generates multi-variant projections (medium, low, high, etc.) into the future. These data include age‐ and sex‐specific breakdowns of fertility, mortality and migration, allowing calculation of detailed demographic indicators. Statistics from the WPP are often cited in academia and by the media.