Estimates for yet deeper prehistory, into the Paleolithic, are of a different nature. At this time, human populations consisted entirely of non-sedentary hunter-gatherer populations, with anatomically modern humans existing alongside archaic human varieties, some of which are still ancestral to the modern human population due to interbreeding with modern humans during the Upper Paleolithic Projections of global human population are generally based on birth rates and death rates, and since these are difficult to predict very far into the future, forecasts of global population numbers and growth rates have changed over time. World population milestones went unnoticed until the 20th century, since there was no reliable data on global population dynamics. [2] The population of the world reached: [3][4] 1 billion in 1804 2 billion in 1928 3 billion in 1961 4 billion in 1975 5 billion in 1988 6 billion in 1999 7 billion in 2011 8 billion in 2022 Old estimates put the global population at: 9 billion by 2037–2043, 15 In world demographics, the world population is the total number of humans currently alive. It was estimated by the United Nations to have exceeded eight billion in mid-November 2022. It took around 300,000 years of human prehistory and history for the human population to reach a billion and only 218 more years to reach 8 billion. List of countries by past and projected future population Population of the present-day top seven most-populous countries, 1800 to 2100. Future projections are based on the 2024 UN's medium-fertility scenario. Chart created by Our World In Data in 2024. This article contains a list of countries by past and projected future population. Demographics of the world Earth has a human population of over 8.2 billion as of 2025, with an overall population density of 50 people per km 2 (130 per sq. mile). Nearly 60% of the world's population lives in Asia, with more than 2.8 billion in the countries of India and China combined. Demographic

history is the reconstructed record of human population in the past. Given the lack of population records prior to the 1950s, there are many gaps in our record of demographic history. Historical demographers must make do with estimates, models and extrapolations. For the demographic methodology, see historical demography. Graph showing population by continent as a percentage of Prehistoric demography Log-log graph depicting estimates of the world population from 10,000 BCE to 2000 CE Prehistoric demography, palaeodemography or archaeological demography is the study of human and hominid demography in prehistory. [1]