Human overpopulation (or human population overshoot) is the concept of a human population becoming too large to be sustained by its environment or resources in the long term. The idea is usually discussed in the context of world population, though it may also concern individual nations, regions, and cities.
Over the past two centuries, the global human population has increased from 1 billion to 8 billion due to medical advancements and improved agricultural productivity. According to the most recent United Nations' projections, "[t]he global population is expected to reach 9.7 billion in 2050 and 10.4 billion in 2100 [assuming] a decline of fertility for countries where large families are still prevalent." Those concerned by this trend argue that they result in levels of resource consumption and pollution which exceed the environment's carrying capacity, leading to population overshoot. The concept is often discussed in relation to other population concerns such as population momentum, biodiversity loss, hunger and malnutrition, resource depletion, and the overall human impact on the environment.
Early discussions of overpopulation in English were spurred by the work of Thomas Malthus. Discussions of overpopulation follow a similar line of inquiry as Malthusianism and its Malthusian catastrophe, a hypothetical event where population exceeds agricultural capacity, causing famine or war over resources, resulting in poverty and depopulation. More recent discussion of overpopulation was popularized by Paul Ehrlich in his 1968 book The Population Bomb and subsequent writings. Ehrlich described overpopulation as a function of overconsumption, arguing that overpopulation should be defined by a population being unable to sustain itself without depleting non-renewable resources.
Modern proponents of the concept have suggested that overpopulation, population growth and overconsumption are interdependent and collectively are the primary drivers of human-caused environmental problems such as climate change and biodiversity loss. Many scientists have expressed concern about population growth, and argue that creating sustainable societies will require decreasing the current global population. Advocates have suggested implementation of population planning strategies to reach a proposed sustainable population.
The topic of overpopulation is controversial, with many demographic experts and environmentalists disputing its premise. Some demographic projections suggest that population growth will end in the 21st century, and some experts believe that global resources can meet this increased demand, avoiding global overpopulation. Some critics argue that attempts to blame environmental issues on overpopulation oversimplify complex social or economic systems, or place blame on developing countries and poor populations—reinscribing colonial or racist assumptions. These critics suggest overconsumption to be treated as an issue separate from population growth.
See also: Population growth
World population has been rising continuously since the end of the Black Death, around the year 1350. The fastest doubling of the world population happened between 1950 and 1986: a doubling from 2.5 to 5 billion people in 37 years, mainly due to medical advancements and increases in agricultural productivity. Due to its impact on the human ability to grow food, the Haber process enabled the global population to increase from 1.6 billion in 1900 to 7.7 billion by November 2018 and, according to the United Nations, 8 billion as of November 2022. Some researchers have analysed this growth in population like other animal populations, human populations predictably grow and shrink according to their available food supply as per the Lotka–Volterra equations, including agronomist and insect ecologist David Pimentel, behavioral scientist Russell Hopfenberg, and anthropologist Virginia Abernethy.
Main article: World population milestones
World population has gone through a number of periods of growth since the dawn of civilization in the Holocene period, around 10,000 BCE. The beginning of civilization roughly coincides with the receding of glacial ice following the end of the last glacial period. Farming allowed for the growth of populations in many parts of the world, including Europe, the Americas and China through the 1600s, occasionally disrupted by plagues or other crisis. For example, the Black Death is thought to have reduced the world's population, then at an estimated 450 million, to between 350 and 375 million by 1400.
After the start of the Industrial Revolution, during the 18th century, the rate of population growth began to increase. By the end of the century, the world's population was estimated at just under 1 billion. At the turn of the 20th century, the world's population was roughly 1.6 billion. By 1940, this figure had increased to 2.3 billion. Dramatic growth beginning in 1950 (above 1.8% per year) coincided with greatly increased food production as a result of the industrialization of agriculture brought about by the Green Revolution. The rate of human population growth peaked in 1964, at about 2.1% per year. Each subsequent addition of a billion humans took less and less time: 33 years to reach three billion in 1960, 14 years for four billion in 1974, 13 years for five billion in 1987, and 12 years for six billion in 1999.
On 14 May 2018, the United States Census Bureau calculated the world population as 7,472,985,269 for that same date and the United Nations estimated over 7 billion. In 2017, the United Nations increased the medium variant projections to 9.8 billion for 2050 and 11.2 billion for 2100. The UN population forecast of 2017 was predicting "near end of high fertility" globally and anticipating that by 2030 over two-thirds of the world population will be living in countries with fertility below the replacement level and for total world population to stabilize between 10 and 12 billion people by the year 2100.
|Continent||Projected 2050 population
by UN in 2017
|Latin America and Caribbean||780 million|
|North America||435 million|
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.
The 2019 projections from the United Nations Population Division show that annual world population growth peaked at 2.1% in 1968, has since dropped to 1.1%, and could drop even further to 0.1% by 2100, which would be a growth rate not seen since pre-industrial revolution days. Based on this, the UN Population Division projects the world population, which is 7.8 billion as of 2020[update], to level out around 2100 at 10.9 billion (the median line), assuming a continuing decrease in the global average fertility rate from 2.5 births per woman during the 2015–2020 period to 1.9 in 2095–2100, according to the medium-variant projection. A 2014 projection has the population continuing to grow into the next century.
However, estimates outside of the United Nations have put forward alternative models based on additional downward pressure on fertility (such as successful implementation of education and family planning goals in the Sustainable Development Goals) which could result in peak population during the 2060-2070 period rather than later.
According to the UN, about two-thirds of the predicted growth in population between 2020 and 2050 will take place in Africa. It is projected that 50% of births in the 5-year period 2095-2100 will be in Africa. Other organizations project lower levels of population growth in Africa based particularly on improvement in women's education and successfully implementing family planning.
By 2100, the UN projects the population in Sub-Saharan Africa will reach 3.8 billion, IHME projects 3.1 billion, and IIASA is the lowest at 2.6 billion. In contrast to the UN projections, the models of fertility developed by IHME and IIASA incorporate women's educational attainment, and in the case of IHME, also assume successful implementation of family planning.Because of population momentum the global population will continue to grow, although at a steadily slower rate, for the remainder of this century, but the main driver of long-term future population growth will be the evolution of the global average fertility rate.
See also: Malthusianism
Concerns about population size or density have a long history: Tertullian, a resident of the city of Carthage in the second century CE, criticized population at the time: "Our numbers are burdensome to the world, which can hardly support us... In very deed, pestilence, and famine, and wars, and earthquakes have to be regarded as a remedy for nations, as the means of pruning the luxuriance of the human race." Despite those concerns, scholars have not found historic societies that have collapsed because of overpopulation or overconsumption.
By the early 19th century, intellectuals such as Thomas Malthus predicted that humankind would outgrow its available resources because a finite amount of land would be incapable of supporting a population with limitless potential for increase. During the 19th century, Malthus' work, particularly An Essay on the Principle of Population, was often interpreted in a way that blamed the poor alone for their condition and helping them was said to worsen conditions in the long run. This resulted, for example, in the English poor laws of 1834 and a hesitating response to the Irish Great Famine of 1845–52.
The first World Population Conference was held in 1927 in Geneva, organised by the League of Nations and Margaret Sanger.
Paul R. Ehrlich's book The Population Bomb became a bestseller upon its release in 1968 and created renewed interest in overpopulation. The book predicted population growth would lead to famine, societal collapse, and other social, environmental and economic strife in the coming decades, and advocated for policies to curb it. The Club of Rome published the influential report The Limits to Growth in 1972, which used computer modelling to similarly argue that continued population growth trends would lead to global system collapse. The idea of overpopulation was also a topic of some works of English-language science fiction and dystopian fiction during the latter part of the 1960s. The United Nations held the first of three World Population Conferences in 1974. Human population and family planning policies were adopted by some nations in the late 20th century in an effort to curb population growth, including in China and India. Albert Allen Bartlett gave more than 1,742 lectures on the threat of exponential population growth starting in 1969.
However, many predictions of overpopulation during the 20th century did not materialise. In The Population Bomb, Elrich stated, "In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now," with later editions changing to "in the 1980s". Despite admitting some of his earlier predictions did not come to pass, Ehlrich continues to advocate that overpopulation is a major issue.
As the profile of environmental issues facing humanity increased during the end of the 20th and the early 21st centuries, some have looked to population growth as a root cause. In the 2000s, E. O. Wilson and Ron Nielsen discussed overpopulation as a threat to the quality of human life.: 37–39 [non-primary source needed] In 2011, Pentti Linkola argued that human overpopulation represents a threat to Earth's biosphere.[non-primary source needed] A 2015 survey from Pew Research Center reports that 82% of scientists associated with the American Association for the Advancement of Science were concerned about population growth. In 2017, more than one-third of 50 Nobel prize-winning scientists surveyed by the Times Higher Education at the Lindau Nobel Laureate Meetings said that human overpopulation and environmental degradation are the two greatest threats facing mankind. In November that same year, the World Scientists' Warning to Humanity: A Second Notice, signed by 15,364 scientists from 184 countries, indicated that rapid human population growth is "a primary driver behind many ecological and even societal threats." Ehlrich and other scientists at a conference in the Vatican on contemporary species extinction linked the issue to population growth in 2017, and advocated for human population control, which attracted controversy from the Catholic church. In 2019, a warning on climate change signed by 11,000 scientists from 153 nations said that human population growth adds 80 million humans annually, and "the world population must be stabilized—and, ideally, gradually reduced—within a framework that ensures social integrity" to reduce the impact of "population growth on GHG emissions and biodiversity loss."
According to the writer and journalist Krithika Varagur, myths and misinformation about overpopulation of Rohingya people in Myanmar is thought to have driven their persecution in the 2010s. The Indian government of Narendra Modi introduced population policies in the 21st century, including offering incentives for sterilization by citing the risks of a "population explosion" although demographers have criticised that basis, with India thought to be undergoing demographic transition and its fertility rate falling. The policies have also received criticism from human and women's rights groups.
In 2020, a quote from David Attenborough about how humans have "overrun the planet" was shared widely online and became his most popular comment on the internet.
The World Wide Fund for Nature (WWF) and Global Footprint Network have argued that the annual biocapacity of Earth has exceeded, as measured using the ecological footprint. In 2006, WWF's Living Planet Report stated that in order for all humans to live with the current consumption patterns of Europeans, we would be spending three times more than what the planet can renew. According to these calculations, humanity as a whole was using by 2006 40% more than what Earth can regenerate. Another study by the WWF in 2014 found that it would take the equivalent of 1.5 Earths of biocapacity to meet humanity's current levels of consumption. However, Roger Martin of Population Matters states the view: "the poor want to get rich, and I want them to get rich," with a later addition, "of course we have to change consumption habits,... but we've also got to stabilise our numbers".
Critics have questioned the simplifications and statistical methods used in calculating ecological footprints. Therefore, Global Footprint Network and its partner organizations have engaged with national governments and international agencies to test the results—reviews have been produced by France, Germany, the European Commission, Switzerland, Luxembourg, Japan and the United Arab Emirates. Some point out that a more refined method of assessing Ecological Footprint is to designate sustainable versus non-sustainable categories of consumption.
Main article: Sustainable population
Attempts have been made to estimate the world's carrying capacity for humans; the maximum population the world can host. A 2004 meta-analysis of 69 such studies from 1694 until 2001 found the average predicted maximum number of people the Earth would ever have was 7.7 billion people, with lower and upper meta-bounds at 0.65 and 98 billion people, respectively. They conclude: "recent predictions of stabilized world population levels for 2050 exceed several of our meta-estimates of a world population limit".
A 2012 United Nations report summarized 65 different estimated maximum sustainable population sizes and the most common estimate was 8 billion. Advocates of reduced population often put forward much lower numbers. Paul R. Ehrlich stated in 2018 that the optimum population is between 1.5 and 2 billion. In 2022 Erhlich and other contributors to the "Scientists' warning on population", including Eileen Crist, William J. Ripple, William E. Rees and Christopher Wolf, stated that environmental analysts put the sustainable level of human population at between 2 and 4 billion people. Geographer Chris Tucker estimates that 3 billion is a sustainable number.
Critics of overpopulation criticize the basic assumptions associated with these estimates. For example, associate professor of gender and sexuality Jade Sasser believes that calculating a maximum of number of humanity is unethical claiming that only some, mostly European former colonial powers, are mostly responsible for unsustainably using up Earth's resources.
Although proponents of human overpopulation have expressed concern that growing population will lead to an increase in global poverty and infant mortality, both indicators have declined over the last 200 years of population growth.
Main article: Human impact on the environment
See also: Environmental impact of agriculture
A number of scientists have argued that human impacts on the environment and accompanying increase in resource consumption threatens the world's ecosystems and the survival of human civilization. The InterAcademy Panel Statement on Population Growth, which was ratified by 58 member national academies in 1994, states that "unprecedented" population growth aggravates many environmental problems, including rising levels of atmospheric carbon dioxide, global warming, and pollution. Indeed, some analysts claim that overpopulation's most serious impact is its effect on the environment. Some scientists suggest that the overall human impact on the environment during the Great Acceleration, particularly due to human population size and growth, economic growth, overconsumption, pollution, and proliferation of technology, has pushed the planet into a new geological epoch known as the Anthropocene.
Some studies and commentary link population growth with climate change. Critics have stated that population growth alone may have less influence on climate change than other factors, such as greenhouse gas emissions per capita. The global consumption of meat is projected to rise by as much as 76% by 2050 as the global population increases, with this projected to have further environmental impacts such as biodiversity loss and increased greenhouse gas emissions. A July 2017 study published in Environmental Research Letters argued that the most significant way individuals could mitigate their own carbon footprint is to have fewer children, followed by living without a vehicle, forgoing air travel, and adopting a plant-based diet. However, even in countries which have both large population growth and major ecological problems, it is not necessarily true that curbing the population growth will make a major contribution towards resolving all environmental problems that can be solved simply with an environmentalist policy approach.
Continued population growth and overconsumption, particularly by the wealthy, have been posited as key drivers of biodiversity loss and contemporary species extinction, with some researchers and environmentalists specifically suggesting this indicates a human overpopulation scenario. The Global Assessment Report on Biodiversity and Ecosystem Services, released by IPBES in 2019, states that human population growth is a factor in biodiversity loss. IGI Global has uncovered the growth of the human population caused encroachment in wild habitats which have led to their destruction, "posing a potential threat to biodiversity components".
Some prominent scientists and environmentalists, including Jared Diamond, E. O. Wilson, Jane Goodall and David Attenborough, contend that population growth is devastating to biodiversity. Wilson for example, has expressed concern when Homo sapiens reached a population of six billion their biomass exceeded that of any other large land dwelling animal species that had ever existed by over 100 times.
Human overpopulation and continued population growth are also considered by some, including animal rights attorney Doris Lin and philosopher Steven Best, to be an animal rights issue, as more human activity means the destruction of animal habitats and more direct killing of animals.: 146
Some commentary has attributed depletion of non-renewable resources, such as land, food and water, to overpopulation and suggested it could lead to a diminished quality of human life. Ecologist David Pimentel was one such proponent, saying "with the imbalance growing between population numbers and vital life sustaining resources, humans must actively conserve cropland, freshwater, energy, and biological resources. There is a need to develop renewable energy resources. Humans everywhere must understand that rapid population growth damages the Earth's resources and diminishes human well-being."
Although food shortages have been warned as a consequence of overpopulation, according to the Food and Agriculture Organization, global food production exceeds increasing demand from global population growth. Food insecurity in some regions is attributable to the globally unequal distribution of food supplies.
Some proponents of overpopulation[who?] warn expansion of agricultural production to meet population growth is likely to have a substantial impact on the environment, and have expressed concern at usable land area becoming limited. The notion that space is limited has been decried by skeptics, who point out that the Earth's population of roughly 6.8 billion people could comfortably be housed an area comparable in size to the state of Texas in the United States (about 269,000 square miles or 696,706.80 square kilometres). Critics and agricultural experts suggest changes to policies relating to land use or agriculture to make them more efficient would be more likely to resolve land issues and pressures on the environment than focusing on reducing population alone.
Water scarcity, which threatens agricultural productivity, represents a global issue that some have linked to population growth. Colin Butler wrote in The Lancet in 1994 that overpopulation also has economic consequences for certain countries due to resource use.
It was speculated by Aldous Huxley in 1958 that democracy is threatened by overpopulation, and could give rise to totalitarian style governments. Physics professor Albert Allen Bartlett at the University of Colorado Boulder warned in 2000 that overpopulation and the development of technology are the two major causes of the diminution of democracy. However, over the last 200 years of population growth, the actual level of personal freedom has increased rather than declined. John Harte has argued population growth is a factor in numerous social issues, including unemployment, overcrowding, bad governance and decaying infrastructure. Daron Acemoglu and others suggested in a 2017 paper that since the Second World War, countries with higher population growth rates experienced the most social conflict.
Some advocates[who?] have suggested societal problems such as hunger and mass unemployment are linked to overpopulation.[verification needed]
According to anthropologist Jason Hickel, the global capitalist system creates pressures for population growth: "more people means more labour, cheaper labour, and more consumers."
A 2021 article in Ethics, Medicine and Public Health argued in light of the COVID-19 pandemic that epidemics and pandemics were made more likely by overpopulation, globalization, urbanization and encroachment into natural habitats.
Several strategies have been proposed to mitigate overpopulation.
Main article: Human population planning
Several scientists (including Paul Ehrlich, Gretchen Daily and Tim Flannery) proposed that humanity should work at stabilizing its absolute numbers, as a starting point towards beginning the process of reducing the total numbers. They suggested several possible approaches, including:
Some scientists including Corey Bradshaw and Barry Brook suggest that, given the "inexorable demographic momentum of the global human population," sustainability can be achieved more rapidly with a short term focus on technological and social innovations, along with reducing consumption rates, while treating population planning as a long term goal.
Education and empowerment of women and giving access to family planning and contraception have a demonstrated impact on reducing birthrates. Many studies conclude that educating girls reduces the number of children they have. One option according to some activists is to focus on education about family planning and birth control methods, and to make birth-control devices like condoms, contraceptive pills and intrauterine devices easily available. Worldwide, nearly 40% of pregnancies are unintended (some 80 million unintended pregnancies each year). An estimated 350 million women in the poorest countries of the world either did not want their last child, do not want another child or want to space their pregnancies, but they lack access to information, affordable means and services to determine the size and spacing of their families[when?]. In the developing world, some 514,000 women die annually of complications from pregnancy and abortion, with 86% of these deaths occurring in the sub-Saharan Africa region and South Asia. Additionally, 8 million infants die, many because of malnutrition or preventable diseases, especially from lack of access to clean drinking water.
Women's rights and their reproductive rights in particular are issues regarded to have vital importance in the debate. Anthropologist Jason Hickel asserts that a nation's population growth rapidly declines - even within a single generation - when policies relating to women's health and reproductive rights, children's health (to ensure parents they will survive to adulthood), and expanding education and economic opportunities for girls and women are implemented. This incentive, however, has been questioned by Rosalind P. Petchesky. Citing her attendance of the 1994 Cairo conference, she reported that overpopulation and birth control were being diverted by feminists into women's rights issues, mostly downplaying the overpopulation issue as only one minor matter of many others. Upon her observation, she argued this was forging many faults and distractions on the main problem of human overpopulation and how to solve it[undue weight? ].
A 2020 paper by William J. Ripple and other scientists argued in favor of population policies that could advance social justice (such as by abolishing child marriage, expanding family planning services and reforms that improve education for women and girls) and at the same time mitigate the impact of population growth on climate change and biodiversity loss. In a 2022 warning on population published by Science of the Total Environment, Ripple, Ehrlich and other scientists appealed to families around the world to have no more than one child and also urged policy-makers to improve education for young females and provide high-quality family-planning services.
Further information: Two-child policy
Ehrlich advocated in The Population Bomb that "various forms of coercion", such as removing tax benefits for having additional children, be used in cases when voluntary population planning policies fail. Some nations, like China, have used strict or coercive measures such as the one-child policy to reduce birth rates. Compulsory or semi-compulsory sterilization, such as for token material compensation or easing of penalties, has also been implemented in many countries as a form of population control.
Another choice-based approach is financial compensation or other benefits by the state offered to people who voluntarily undergo sterilization. Such policies have been introduced by the government of India.
An argument for space colonization is to mitigate proposed impacts of overpopulation of Earth, such as resource depletion. If the resources of space were opened to use and viable life-supporting habitats were built, Earth would no longer define the limitations of growth. Although many of Earth's resources are non-renewable, off-planet colonies could satisfy the majority of the planet's resource requirements. With the availability of extraterrestrial resources, demand on terrestrial ones would decline. Proponents of this idea include Stephen Hawking and Gerard K. O'Neill.Others including cosmologist Carl Sagan and science fiction writers Arthur C. Clarke, and Isaac Asimov, have argued that shipping any excess population into space is not a viable solution to human overpopulation. According to Clarke, "the population battle must be fought or won here on Earth". The problem for these authors is not the lack of resources in space (as shown in books such as Mining the Sky), but the physical impracticality of shipping vast numbers of people into space to "solve" overpopulation on Earth.
Despite the increase in population density within cities (and the emergence of megacities), UN Habitat Data Corp. states in its reports that urbanization may be the best compromise in the face of global population growth. Cities concentrate human activity within limited areas, limiting the breadth of environmental damage. UN Habitat says this is only possible if urban planning is significantly improved.
Paul Ehrlich proposed in The Population Bomb that rhetoric supporting the increase of city density is a means of avoiding dealing with what he views as the root problem of overpopulation and has been promoted by what he views as the same interests that have allegedly profited from population increase (such as property developers, the banking system which invests in property development, industry, and municipal councils). Subsequent authors point to growth economics as driving governments seek city growth and expansion at any cost, disregarding the impact it might have on the environment.
See also: Population ethics
The concept of human overpopulation, and its attribution as a cause of environmental issues, are controversial.
Some critics, including Joel E. Cohen, Nicholas Eberstadt, Fred Pearce, Dominic Lawson and Betsy Hartmann, refer to overpopulation as a myth. Predicted exponential population growth or any "population explosion" did not materialise; instead, population growth slowed. Critics suggest that enough resources are available to support projected population growth, and that human impacts on the environment are not attributable to overpopulation.
According to libertarian think tank the Fraser Institute, both the idea of overpopulation and the alleged depletion of resources are myths; most resources are now more abundant than a few decades ago, thanks to technological progress. The Institute also questions the sincerity of advocates of population control in poor countries.
Demographer Nicholas Eberstadt has criticised the idea of overpopulation, saying that "overpopulation is not really overpopulation. It is a question of poverty".
A 2020 study in The Lancet concluded that "continued trends in female educational attainment and access to contraception will hasten declines in fertility and slow population growth", with projections suggesting world population would peak at 9.73 billion in 2064 and fall by 2100. Media commentary interpreted this as suggesting overconsumption represents a greater environmental threat as an overpopulation scenario may never occur.
Some human population planning strategies advocated by proponents of overpopulation are controversial for ethical reasons. Those concerned with overpopulation, including Paul Ehrlich, have been accused of influencing human rights abuses including forced sterilisation policies in India and under China's one-child policy, as well as mandatory or coercive birth control measures taken in other countries.
Further information: Feminization of poverty
Influential advocates such as Betsy Hartmann consider the "myth of overpopulation" to be destructive as it "prevents constructive thinking and action on reproductive rights," which acutely affects women and communities of women in poverty. The 1994 International Conference on Population and Development (ICPD) defines reproductive rights as "the basic right of all couples and individuals to decide freely and responsibly the number, spacing, and timing of their children and to have the information to do so."
See also: Ecofascism
The argument of overpopulation has been criticized by some scholars and environmentalists as being racist and having roots in colonialism and white supremacy, since control and reduction of human population is often focused on the global south, instead of on overconsumption and the global north, where it occurs. Paul Ehrlich's Population Bomb begins with him describing first knowing the "feel of overpopulation" from a visit to Delhi, which some critics have accused of having racial undertones. George Monbiot has said "when affluent white people wrongly transfer the blame for their environmental impacts on to the birthrate of much poorer brown and black people, their finger-pointing reinforces [Great Replacement and white genocide conspiracy] narratives. It is inherently racist." Overpopulation is said to be a common component of ecofascist ideology.
Scholar Heather Alberro argues to reject the overpopulation argument, stating that the human population growth is rapidly slowing down, the underlying problem is not the number of people, but how resources are distributed and that the idea of overpopulation could fuel a racist backlash against the population of poor countries.
Main article: List of population concern organizations
The following organizations advocate for a limit to human population growth, although their focus may be on related issues such as environmental protection:
Much less frequently mentioned are, however, the ultimate drivers of those immediate causes of biotic destruction, namely, human overpopulation and continued population growth, and overconsumption, especially by the rich. These drivers, all of which trace to the fiction that perpetual growth can occur on a finite planet, are themselves increasing rapidly.
When is an area overpopulated? When its population cannot be maintained without rapidly depleting nonrenewable resources  (or converting renewable resources into nonrenewable ones) and without decreasing the capacity of the environment to support the population. In short, if the long-term carrying capacity of an area is clearly being degraded by its current human occupants, that area is overpopulated.
On the contrary, we devoted an entire section to the interacting and inter-dependent components of overpopulation and overconsumption, which are, for instance, also central tenets of the recent Economics of Biodiversity review (Dasgupta, 2021). Therein, the dynamic socio-ecological model shows that mutual causation drives modern socio-ecological systems. Just as it is incorrect to insist that a large global population is the sole underlying cause of biodiversity loss, so too is it naïve and incorrect to claim that high consumption alone is the cause, and so forth.
Growing human populations have significant implications for our demands on Nature, including for future patterns of global consumption.
Population growth can end and numbers can be gradually lowered within a human-rights framework. Lowering human numbers is achievable by expanding and protecting human rights, especially for children and women . . . A smaller human population will facilitate the conservation of a biodiverse planet while also supporting a higher quality of life for people by lowering pollution levels, preempting resource conflicts, ameliorating overcrowding in urban centers, and empowering girls and women
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The power of population is so superior to the power in the earth to produce subsistence for man, that premature death must in some shape or other visit the human race
Calculations show that, maintaining the actual rate of population growth and resource consumption, in particular forest consumption, we have a few decades left before an irreversible collapse of our civilisation.
Large populations and their continued growth are also drivers of soil degradation and biodiversity loss. More people means that more synthetic compounds and dangerous throw-away plastics are manufactured, many of which add to the growing toxification of the Earth.
Twenty-nine members of the AWG supported the Anthropocene designation and voted in favour of starting the new epoch in the mid-twentieth century, when a rapidly rising human population accelerated the pace of industrial production, the use of agricultural chemicals and other human activities.
Human population has exceeded historical natural limits, with 1) the development of new energy sources, 2) technological developments in aid of productivity, education and health, and 3) an unchallenged position on top of food webs. Humans remain Earth’s only species to employ technology so as to change the sources, uses, and distribution of energy forms, including the release of geologically trapped energy (i.e. coal, petroleum, uranium). In total, humans have altered nature at the planetary scale, given modern levels of human-contributed aerosols and gases, the global distribution of radionuclides, organic pollutants and mercury, and ecosystem disturbances of terrestrial and marine environments. Approximately 17,000 monitored populations of 4005 vertebrate species have suffered a 60% decline between 1970 and 2014, and ~1 million species face extinction, many within decades. Humans' extensive 'technosphere', now reaches ~30 Tt, including waste products from non-renewable resources.
By 2050 the human population will top 9 billion, and world meat consumption will likely double.
The overarching driver of species extinction is human population growth and increasing per capita consumption.
All of these are related to human population size and growth, which increases consumption (especially among the rich), and economic inequity.
Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.)
Human overpopulation is an animal rights issue as well as an environmental issue and a human rights issue. Human activities, including mining, transportation, pollution, agriculture, development, and logging, take habitat away from wild animals as well as kill animals directly.
And of course capitalism itself creates pressures for population growth: more people means more labour, cheaper labour, and more consumers. These pressures filter into our culture, and even into national policy: countries like France and Japan are offering incentives to get women to have more children, to keep their economies growing.