Population is the term typically used to refer to the number of people in a single area. Governments conduct a census to quantify the size of a resident population within a given jurisdiction. The term is also applied to animals, microorganisms, and plants, and has specific uses within such fields as ecology and genetics.
The Population Bomb is a 1968 book co-authored by former Stanford University professor Paul R. Ehrlich and former Stanford senior researcher in conservation biology Anne H. Ehrlich. From the opening page, it incorrectly predicted worldwide famines due to overpopulation, as well as other major societal upheavals, and advocated immediate action to limit population growth. Fears of a "population explosion" existed in the mid-20th century baby boom years, but the book and its authors brought the idea to an even wider audience.
Human population planning is the practice of managing the growth rate of a human population. The practice, traditionally referred to as population control, had historically been implemented mainly with the goal of increasing population growth, though from the 1950s to the 1980s, concerns about overpopulation and its effects on poverty, the environment and political stability led to efforts to reduce population growth rates in many countries. More recently, however, several countries such as China, Japan, South Korea, Russia, Iran, Italy, Spain, Finland, Hungary and Estonia have begun efforts to boost birth rates once again, generally as a response to looming demographic crises.
Population ageing is an increasing median age in a population because of declining fertility rates and rising life expectancy. Most countries have rising life expectancy and an ageing population, trends that emerged first in developed countries but are now seen in virtually all developing countries. That is the case for every country in the world except the 18 countries designated as "demographic outliers" by the United Nations. The aged population is currently at its highest level in human history. The UN predicts the rate of population ageing in the 21st century will exceed that of the previous century. The number of people aged 60 years and over has tripled since 1950 and reached 600 million in 2000 and surpassed 700 million in 2006. It is projected that the combined senior and geriatric population will reach 2.1 billion by 2050. Countries vary significantly in terms of the degree and pace of ageing, and the UN expects populations that began ageing later will have less time to adapt to its implications.
Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to 7.9 billion in 2020. The UN projected population to keep growing, and estimates have put the total population at 8.6 billion by mid-2030, 9.8 billion by mid-2050 and 11.2 billion by 2100. However, some academics outside the UN have increasingly developed human population models that account for additional downward pressures on population growth; in such a scenario population would peak before 2100. Others have challenged many recent population projections as having underestimated population growth.
Malthusianism is the theory that population growth is potentially exponential, according to the Malthusian growth model, while the growth of the food supply or other resources is linear, which eventually reduces living standards to the point of triggering a population decline. This event, called a Malthusian catastrophe occurs when population growth outpaces agricultural production, causing famine or war, resulting in poverty and depopulation. Such a catastrophe inevitably has the effect of forcing the population to "correct" back to a lower, more easily sustainable level. Malthusianism has been linked to a variety of political and social movements, but almost always refers to advocates of population control.
Human overpopulation describes a concern that human populations may become too large to be sustained by their environment or resources in the long term. The topic is usually discussed in the context of world population, though it may concern individual nations, regions, and cities.
Population Matters, formerly known as the Optimum Population Trust, is a UK-based charity that addresses population size and its effects on environmental sustainability. It considers population growth as a major contributor to environmental degradation, biodiversity loss, resource depletion and climate change. The group promotes ethical, choice-based solutions through lobbying, campaigning and awareness-raising.
World Population Day is an annual event, observed on July 11 every year, which seeks to raise awareness of global population issues. The event was established by the Governing Council of the United Nations Development Programme in 1989. It was inspired by the public interest in Five Billion Day on July 11, 1987, the approximate date on which the world's population reached five billion people. World Population Day aims to increase people's awareness on various population issues such as the importance of family planning, gender equality, poverty, maternal health and human rights.
The population of Africa has grown rapidly over the past century and consequently shows a large youth bulge, further reinforced by a low life expectancy of below 50 years in some African countries. Total population as of 2020 is estimated to be more than 1.3 billion, with a growth rate of more than 2.5% p.a. The total fertility rate for Africa is 4.7 as of 2018, the highest in the world according to the World Bank. The most populous African country is Nigeria with over 206 million inhabitants as of 2020 and a growth rate of 2.6% p.a.
The United Nations Population Fund designated 12 October 1999, as the approximate day on which world population reached six billion following the birth of Adnan Mević, the first son of Fatima Helać and Jasminko Mević, in Sarajevo, Bosnia and Herzegovina. It was officially designated The Day of Six Billion.
Demographic dividend, as defined by the United Nations Population Fund (UNFPA), is "the economic growth potential that can result from shifts in a population’s age structure, mainly when the share of the working-age population is larger than the non-working-age share of the population ". In other words, it is “a boost in economic productivity that occurs when there are growing numbers of people in the workforce relative to the number of dependents”. UNFPA stated that “A country with both increasing numbers of young people and declining fertility has the potential to reap a demographic dividend."
In demographics, the world population is the total number of humans currently living. 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 one billion and only 222 years more to reach 8 billion.
In environmental science, the concept of overshoot means demand in excess of regeneration. It can apply to animal populations and people. Environmental science studies to what extent human populations through their resource consumption have risen above the sustainable use of resources. For people, "overshoot" is that portion of their demand or ecological footprint which must be eliminated to be sustainable. Excessive demand leading to overshoot is driven by both consumption and population.
7 Billion Actions is a worldwide campaign established by the United Nations Population Fund (UNFPA) in 2011 to commemorate the world population milestone of 7 billion people. UNFPA is a United Nations organization that works on population and development issues, with an emphasis on reproductive health and gender equality. 7 Billion Actions works with multiple corporations, organizations and individuals to address the 7 Key Issues such as poverty, gender equality, youth, ageing, urbanization, environment, and reproductive health and rights. The UN has declared the World Population surpassing 7 billion on 31 October 2011. Prior to this date, the UN celebrated the Day of Six Billion in October 1999.
Earth has a human population of over 8 billion as of 2023, with an overall population density of 50 people per km2, excluding Antarctica. Nearly 60% of the world's population lives in Asia, with almost 2.8 billion in the countries of China and India combined. The percentage shares of China, India and rest of South Asia of the world population have remained at similar levels for the last few thousand years of recorded history. The world's literacy rate has increased dramatically in the last 40 years, from 66.7% in 1979 to 86.3% today. Lower literacy levels are mostly attributable to poverty. Lower literacy rates are found mostly in South Asia and Sub-Saharan Africa. The world's largest ethnic group is Han Chinese, constituting over 19% of the global population in 2011. In terms of the largest number of native speakers, Mandarin is the world's most spoken language.
The Day of Seven Billion, 31 October 2011, is the day that was officially designated by the United Nations Population Fund (UNFPA) as the approximate day on which the world's population reached seven billion people. United Nations Secretary General Ban Ki-moon spoke at the United Nations building in New York City on this new milestone in the size of world population and the issues that it will raise, along with promoting the UNFPA's new program named 7 Billion Actions, which will seek to "build global awareness around the opportunities and challenges associated with a world of seven billion people" and inspire individuals and organizations to take action. It was succeeded by the Day of Eight Billion on 15 November 2022.
Population projections are attempts to show how the human population statistics might change in the future. These projections are an important input to forecasts of the population's impact on this planet and humanity's future well-being. Models of population growth take trends in human development and apply projections into the future. These models use trend-based-assumptions about how populations will respond to economic, social and technological forces to understand how they will affect fertility and mortality, and thus population growth.
World population milestones went unnoticed until the 20th century, since there was no reliable data on global population dynamics.
Sustainable population refers to a proposed sustainable human population of Earth or a particular region of Earth, such as a nation or continent. Estimates vary widely, with estimates based on different figures ranging from 0.65 billion people to 9.8 billion, with 8 billion people being a typical estimate. Projections of population growth, evaluations of overconsumption and associated human pressures on the environment have led to some to advocate for what they consider a sustainable population. Proposed policy solutions vary, including sustainable development, female education, family planning and broad human population planning.
