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April 10, 2026
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"In recent decades, support for family planning has waned, and global fertility decline has decelerated as a result. Projections calibrated across the decades of strong family planning support have not acknowledged this change and are consequently underestimating global population growth. Scenarios used to model sustainable futures have used overly optimistic population projections while inferring these outcomes will happen without targeted measures to bring them about. Unless political will is rapidly restored for voluntary family planning programs, the global population will almost certainly exceed 10 billion, rendering sustainable food security and a safe climate unachievable."
"Putting an end to the population explosion will not of itself save the ecosphere, but not ending it will add greatly to the dangers the planet faces. The environment can sustain a quality of life for just so many people."
"In what year will the human population grow too large for the Earth to sustain? The answer is about 1970, according to research by the . In 1970, the planet's 3 and a half billion people were . But on this New Year's Day, the population is 8 billion. Today, wild plants and animals are running out of places to live."
"... Homo sapiens have been around for about 200,000 years and we are struggling to provide 7 billion of us with sufficient food, clothing, and shelter to lead decent lives. There cannot be an economist on the planet who thinks Earth could support 7.168 trillion people. Human population growth cannot go on forever, no matter how optimistic economists might be."
"Human overpopulation, the ever-increasing power of our technology, and the demand of our omnicidal, neoliberal economic system of infinite growth on the basis of finite resources threaten the earth with total destruction."
"Ever since Malthus, at least, it has been clear that means of subsistence do not grow as fast as population. No one has ever liked the idea that famine, plague, and war are nature's way of redressing the imbalance -- Malthus himself suggested that the operation of "preventive checks," which serve to reduce the birth rate, might help prolong the interval between such events. And in the two hundred years since Malthus sat down to pen his essay, there has been no worldwide cataclysm. But in the same two centuries world population has grown exponentially while irreplaceable resources were used up. Some kind of adjustment is inevitable. Today, many people who are concerned about overpopulation and environmental degradation believe that human actions can avert catastrophe. The prevailing view holds that a stable population that does not tax the environment's "carrying capacity" would be sustainable indefinitely, and that this state of equilibrium can be achieved through a combination of birth control, conservation, and reliance on "renewable" resources. Unfortunately, worldwide implementation of a rigorous program of birth control is politically impossible. Conservation is futile as long as population continues to rise. And no resources are truly renewable."
"Around 8,000 BC, world population was something like five million. By the time of [the birth of Jesus] Christ, it was 200 to 300 million. By 1650, it was 500 million, and by 1800 it was one billion. The population of the world reached two billion by 1930. By the beginning of the '60s it was three billion; in 1975 it was four billion; and after only eleven more years it was five billion. This cannot go on forever; collapse is inevitable. The only question is when."
"People who believe that a stable population can live in balance with the productive capacity of the environment may see a slowdown in the growth of population and energy consumption as evidence of approaching equilibrium. But when one understands the process that has been responsible for population growth, it becomes clear that an end to growth is the beginning of collapse. Human population has grown exponentially by exhausting limited resources, like yeast in a vat or reindeer on St. Matthew Island, and is destined for a similar fate."
"As human populations expand they necessarily appropriate ecological space required by other species. Human âcompetitive displacementâ of non-human organisms from their habitats and food sources is now the greatest contributing factor to . Consider that with only 0.01 % of total Earthly , H. sapiensâ expansion has eliminated 83 % of wild animal and 50 % of natural plant biomass. From a fraction of 1 % ten millennia ago, humans now constitute 36 %, and our domestic livestock another 60 %, of the planetâs much expanded mammalian biomass compared to only 4 % for all wild species combined. Similarly, domestic poultry now comprise 70 % of Earthâs remaining avian biomass. Meanwhile, commercial fishing depletes the oceans at the expense of rapidly declining marine mammals and birds. Seabirds are the most threatened bird group, with a 70 % community-level population decline between 1950 and 2010."
"Population estimates are usually based on demographic data alone with no consideration of exogenous factors. This is unrealistic. For living organisms, the fact of their own existence ensures that no environment or habitat remains ideal for long. As the subject population expands, it will invariably use up any crucial resource in fixed supply. Even renewable resources can be depleted once the population goes into âovershootâ, a situation in which aggregate consumption exceeds food speciesâ recovery rates or waste accumulation exceeds natural assimilative capacity. The rise and fall of reindeer populations introduced to two previously unoccupied (by reindeer) Pribilof Islands in the early 20th century is a classic example. Collapse was attributed to overgrazed food sources (primarily lichen) abetted by the stress of exceptionally cold winter."
"...for most of our speciesâ time on Earthâincluding most of the agricultural eraâhumanityâs natural propensity to expand has been held in check by negative feedback, e.g., food and other resource shortages, disease, and inter-group conflict. Circumstances changed with the scientific/industrial revolution, particularly the increasingly widespread use of fossil fuels. It took 200,000 â 350,000 years for human numbers to reach one billion early in the 19th Century, but only 200 years (as little as 1/1750th as much time!) to balloon another seven-fold by early in the 21st Century. Improvements in medicine, public sanitation, and population health contributed to this expansion, but coal, oil, and gas made it possible. Fossil fuels are the energetic means by which humans extract, transport, and transform the prodigious quantities of food and other material resources into the products needed to support our burgeoning billions. More than any other factor, fossil fuels enabled H. sapiens to eliminate or reduce normal negative feedbacks. Freed from historic constraints, our species was, at last, able to exhibit its full potential for geometric growth."
"Humanity is already far into ecological overshoot: we are learning the hard way that the ecosphere under stress is still immeasurably more complex than even the global human enterprise. It can generate a vastly larger arsenal of negative feedbacks in response to human excesses than any imaginable human control system can match."
"Humans invade and populate all accessible favourable habitats; human populations use up all available resources; under favourable conditions, human populations are capable of exponential growth. [âŚ] The industrial/scientific revolution spawned technologies, particularly improvements in public sanitation and disease control, that greatly reduced death rates while fossil fuels alleviated food and resource shortages. With the suppression of negative factors, positive feedback prevailed; between the early 1800s and 2023, the human population exploded from one to eight billion. Meanwhile, what we now call âneoliberal economicsâ began taking form in the late 1800s. In just two centuries, the human population grew eight times larger than the maximum attained over the previous 3000 centuries, and the world economy grew 100-fold in real terms! [âŚ] Overshoot may be a quasi-natural phenomenon, but it is also a potentially terminal condition. There are now about 80 cities in the world with populations in excess of five millionâeach has more people than existed on the entire planet at the dawn of agriculture 10,000 years ago. [âŚ] Life in higher-income countries just seemed to be getting better and better, at least in material terms. Little wonder that by the 1950s, MTI governments and international institutions everywhere were adopting the neoliberal vision of perpetual economic and population growth via continuous technological advance as the dominant development narrative of global culture. There are, of course, significant problemsâall this occurred on a finite, non-growing planet with serious history. With nurture-reinforcing-nature in propelling the expansionist juggernaut, the human enterprise surged into ecological overshoot; resource consumption and waste production are overwhelming the bio-productive and waste assimilation capacities of the ecosphere. This is not merely an aesthetic concern: the functional integrity of the ecosphere is essential for human existence. Overshoot may be a quasi-natural phenomenon, but it is also a potentially terminal condition."
"The current human population is 14,000-fold larger than the average populations of other mammal species of similar body size! [âŚ] If humans were a typical mammal whose global population corresponded to the arithmetic mean (average) of populations of mammals of similar body size, there would be only 500,000 people on Earth!"
"Almost all of todayâs low-energy countries have a population density so great that it perpetuates dependence on intensive manual agriculture, which alone can yield barely enough food for their people. They do not have enough acreage, per capita, to justify using domestic animals or farm machinery, although better seeds, better soil management, and better hand tools could bring some improvement. A very large part of their working population must nevertheless remain on the land, and this limits the amount of surplus energy that can be produced. Most of these countries must choose between using this small energy surplus to raise their very low standard of living or [to] postpone present rewards for the sake of future gain by investing the surplus in new industries. The choice is difficult because there is no guarantee that todayâs denial may not prove to have been in vain. This is so because of the rapidity with which public health measures have reduced mortality rates, resulting in population growth as high [as] or even higher than that of the high-energy nations. Theirs is a bitter choice; it accounts for much of their anti-Western feeling and may well portend a prolonged period of world instability."
"The doubling of life expectancy is largely down to medical advances. Without medical care, weâd probably be at a much lower population level. I canât find projections, but given that even some fairly routine injuries and sicknesses would be life-threatening without medical intervention, one would expect a more pyramidal pyramid, and 2 billion people doesnât seem unreasonable to me. This is also amplified by [there] being [fewer] people to innovate ideas like the green revolution, which [led] to higher populations. In nature, population overshoot is usually remedied by a higher die-off rate, not a lower birth rate. But humans think that medical care and increased lifetimes are a sign of progress. Medical advances can even allow some who wouldnât have been able to have children to have children, thus exacerbating overshoot."
"A lot of technologies have been utilised in storing food or growing more of it. And we know that increased access to food increases population size. The reverse is also true, of course, so we should expect population to fall as harvests come under stress from the effects of climate change."
"Humans are a species, so they are no different in needing to reproduce to propagate their traits, which may eventually lead to what would be considered a new species, though that would likely take tens or hundreds of thousands of years. If our ancestors had considered the effects of what they were doing, why some prey species appeared to disappear, for example, then we wouldnât be here, as weâd limit what we did, how we expanded, how we spread. Humans would, at best, have remained a very limited species, if it survived at all. But that is not the way life works. Clearly, we have followed the maximum power principle, since weâre a species, and so consume as much energy and resources as we can. In basic terms, a body needs food for energy and humans have figured out how to produce increasing quantities of food (at least in terms of calories) using agriculture, machines, artificial fertilisers and pesticides. This has enabled an explosion in population in a positive feedback loop (with higher population forecast, we figure out how to support that population, leading to more agriculture and higher yields, so we end up with a higher population). The huge success of agriculture and mechanisation, has lead to almost no human being involved in the production of the food that keeps us alive, so weâve had to invent other ways to kill our time. We now have a huge variety of products and services to help us kill our time before we die. Some of it is pleasurable so we want to do more of it and invent new ways to live. All the time, killing more of the rest of life. But getting here was inevitable because we are a species and donât have free will to counter those inbuilt drives."
"As food makes babies perhaps the critical development was agriculture but then without fossil fuels, we could never have produced as much food as we do now, and deliver it across the world. But then, if we hadnât started cooking food, we might not have been clever enough to figure out how to use fossil fuels to produce food. And without language, we could never have communicated complex ideas about agriculture, tool making and the use of fossil fuels. So we go round and round."
"It is often said that humans are in overshoot. What does that mean? In simple terms, it means exceeding a limit. However, if a limit has been exceeded, then how is it a limit? People usually refer to overshoot as exceeding the carrying capacity of the planet. The ability for the planet to support the current population of humans. And yet here we are. Humans have apparently been in overshoot territory for a long time, but that hasnât affected the numbers. Indeed, the population of humans continues to grow."
"We have well over 8 billion people on this planet. All ecosystems have been perturbed, and wildlife has been hugely depleted by over 70% in just the last half century. Deforestation continues apace at almost 5 million hectares per year. So, itâs impossible for all humans to live sustainably right now. If a few chose, and succeeded, to live sustainably, it would have no measurable effect on the planet."
"It is apparently futile only to insist that the more backÂward countries restrict their birth rates. What is needed most of all is economic and technical assistance to these countries. This assistance must be of such scale and generosity that it is unlikely before the estrangement in the world and the egotistical, narrow-minded approach to relations between nations and races are eliminated."
"Government policy, legislation on the family and marriage, and propaganda should not encourage an increase in the birth rates of advanced countries while demanding that it be curtailed in underdeveloped countries that are receiving assistance. Such a two-faced game would produce nothing but bitterness and nationalism."
"I want to emphasize that the question of regulating birth rates is highly complex and that any standardized, dogmatic solution "for all time and all peoples" would be wrong."
"...increasingly, technology has come up against the law of unexpected consequences. Advances in health care have lengthened life spans, lowered infant-mortality rates, and, thus, aggravated the population problem."
"As human beings, with over 8 billion of us on planet Earth at present, we now find ourselves in a very analogous situation to both the early cyanobacteria from over 2 billion years ago and the yeast cells one would culture within a nutrient-rich broth in a petri dish. It isnât that weâre in danger of transforming our planet into an uninhabitable hellscape, as nothing weâve done or are in the process of doing is going to have a catastrophic effect of that magnitude. However, there are a number of ways that weâre polluting, destroying, or depleting our environment in ways that not only are non-renewable and unsustainable, but that are going to have negative downstream effects that impact future humans, hundreds and even thousands of years down the line, in ways that most of us arenât prepared to fully reckon with. And thatâs unfortunate, because we should be prepared. After all, unlike yeast, cyanobacteria, or any other species thatâs impacted its environment due to its collective, accumulated actions, we can not only detect and quantify the effects weâre having, but can choose to change our action at any time."
"Erroneous belief about population growth has cost dearly. In poor countries, it has directed attention away from the factor that we now know is central in a country's economic development, its economic and political system. And in rich countries, misdirected attention to population growth and its... consequence of natural-resource shortages has caused waste through such programs as now-abandoned synthetic fuel programs, and the useless development of airplanes that would be appropriate for an age of greater scarcity."
"Adding more people causes problems, but people are also the means to solve these problems. The main fuel to speed our progress is our stock of knowledge, and the brake is our lack of imagination. The ultimate resource is peopleâskilled, spirited, and hopeful people who will exert their wills and imaginations for their own benefit, and inevitably they will benefit not only themselves but the rest of us as well."
"Capitalist elites seeking to increase the size of their labour force used pro-natalist state policies to prevent women from practicing family planning. [...] We should not ignore the relationship between population growth and ecology, but we must not treat these as operating in a social and political vacuum."
"History upon Terra tells us what horrors follow upon religious mandates of unlimited reproduction."
"Malthusian predictions that relentless population growth will outstrip food production and trigger starvation worldwide have recurred over the centuries. They have come and then gone as farmers have deployed new technologies to increase food output. Even now, enough food is being produced to adequately feed every person on the planet; the fact that nearly one billion people are nonetheless going hungry is a damning indictment of the world's food-distribution system. But since demand is growing, production will also have to increase in the years ahead. With the world's population expected to expand to more than nine billion by 2050 and much of that growth occurring in China, India, and other countries where living standards are rising fast, global food production will need to increase by 70-100 percent in order to keep pace and feed the already chronically hungry. This is a mighty challenge: all the more so because given current soil technology and environmental concerns, more food will have to be produced on roughly the same amount of arable land -- and with less water than is used now and at a time when both growing demand for biofuels and changing climate patterns are also putting pressure on production. Where will the needed rise in food supplies come from, and how quickly can the distribution problems be solved?"
"Given the Maoist position that a large population was a âresourceâ, rather than a burden, for the Communist state, it was politically incorrect to advocate population control [either by diet or medicine]."
"Supporting large families and unchecked growth (of which the greatest parameter is population increase) is a mantra which religion and authority have preached for thousands of years. Religions always need more clergy to reap donations from, and leaders more voters to turn into soldiers for their next war, or to make the gross (as opposed to per capita) GDP figures look good. We are being farmed, we have always been farmed for thousands of years by an economic system that prioritises cold hard profit figures over real prosperity. Competition fuels growth even more, as humans are extremely territorial. The problem with the existence of countries is that they speed up civilisational collapse. They all end up competing for economic and population growth, therefore significantly accelerating civilisational overshoot and collapse."
"Thanks to the discovery and exploitation of fossil fuels, humans (really just a small minority of them) are able to live richer lives today than even the queens and kings of yore could have dreamed of. Furthermore, weâve used some of those finite resources to increase food supplies and to expand the human population, which provides the economic system with both more workers and more consumers, a necessity to keep the economy growing under our current economic model. The worldâs population increased from 1.6 billion in 1900 to 7 billion today, and we add about 80 million more each year. Humans have quickly become the most numerous megafauna on the planet."
"Humans, because of their intelligence, have found ways to [temporarily] defeat survival of the fittest. As areas get overpopulated, humans have moved to areas where they have a better chance of survival. Humans have found ways to increase food supply, through the use of fertilizers, pesticides, irrigation, and refrigeration, all of which require fossil fuels. They have developed trade, so that so areas with shortfalls can benefit from surpluses elsewhere. Humans have developed a world financial system, which has helped enable worldwide trade. The financial system has also allowed investors to pay for goods after they are put into service, so that the cash flow resulting from an investment can be used (after the fact) to pay for the cost of the investment. This enables investment, and faster use of resources, including energy resources. One of the reasons for continued upward population pressure is the fact that humans have evolved to live beyond their reproductive years. In their declining years, humans often need assistance, either from their offspring or from a public pension program, or both. Because of concern for their own old age, people without pensions tend to have enough children so that there is a significant chance that a child of the right sex will survive to adulthood. With improving medical care, this tends to lead to [an] ever-rising population."
"As long as the worldâs population is rising, even in lesser developed countries, there is going to be a continuing need for more food, clothing and housing. This is an issue we donât seem to be able even to talk about. It may offend people."
"The energy resource that we learned to develop this time is fossil fuels, starting with coal about 1800. World population was able to expand greatly because of additional food production permitted by fossil fuels and because of improvements in hygiene. A period of stagflation began in the 1970s, when we first encountered problems with US oil production and spiking oil prices. Now, the question is whether we are approaching the Crisis Stage as described by Turchin and Nefedov."
"As energy supplies deplete, we will increasingly need to âchoose our battles.â In the past, humans have been able to win many battles against nature. However, as energy per capita declines in the future, we will be able to win fewer and fewer of these battles against nature, such as our current battle with COVID-19. At some point, we may simply need to let the chips fall where they may. The world economy seems unable to accommodate 7.8 billion people, and we will have no choice but to face this issue."
"Many people believe that humans can have a sustainable future by using solar panels and wind turbines. Unfortunately, the only truly sustainable course, in terms of moving in cycles with nature, is interacting with the environment in a manner similar to the approach used by chimpanzees and baboons. Even this approach will eventually lead to new and different species predominating. Over a long period, such as 10 million years, we can expect the vast majority of species currently alive will become extinct, regardless of how well these species fit in with natureâs plan. The key to the relative success of animals such as chimpanzees and baboons is living within a truly circular economy. Sunlight falling on trees provides the food they need. Waste products of their economy come back to the forest ecosystem as fertilizer. Pre-humans lost the circular economy when they learned to control fire over one million years ago, when they were still hunter-gatherers. With the controlled use of fire, cooked food became possible, making it easier to chew and digest food. The human body adapted to the use of cooked food by reducing the size of the jaw and digestive tract and increasing the size of the brain. This adaptation made pre-humans truly different from other animals. With the use of fire, pre-humans had many powers. They spent less time chewing, so they could spend more time making tools. They could burn down entire forests, if they so chose, to provide a better environment for the desired types of wild plants to grow. They could use the heat from fire to move to colder environments than the one to which they were originally adapted, thus allowing a greater total population. Once pre-humans could outcompete other species, the big problem became diminishing returns. For example, once the largest beasts were killed off, only smaller beasts were available to eat. The amount of effort required to kill these smaller beasts was not proportionately less, however."
"⌠the problem the world is facing today is like one that smaller economies have faced, over and over, in the past: The population has become too large for the economyâs resource base, which now includes fossil fuels. Todayâs leaders reframe the problem as voluntarily moving away from fossil fuels to prevent climate change in order to make the situation sound less frightening."
"We are dealing with an age-old problem: Humans are able to outsmart other animals, and for this reason, human populations tend to rise except when external conditions are quite adverse."
"History shows a repeated pattern of overshoot and collapse. A population would grow until the carrying capacity of the local area was reached. Food surpluses would become lower and lower, so less food could be saved up for fluctuations in rainfall and temperature. Eventually, civilizations would succumb to one or another problem: disease, attack by a neighboring group, climate fluctuations, or governments overthrown by unhappy citizens. We tell ourselves that overshoot and collapse cannot happen now, but human population is high relative to fossil fuel resources, and intermittent wind and solar are not working out well as substitutes."
"Humans are smarter than other animals, allowing the population of humans to grow, while the population of many other species tends to fall. [âŚ] The large rise in the population of the less advanced economies contributes to the huge number of immigrants wanting new homes in higher-income countries. [âŚ] The issue is that available resources do not rise fast enough (in the area, or with the technology available) to provide enough physical goods and services for the population. If a new approach can be developed, or a neighboring area with additional resources can be conquered, [the] population can start to grow again. [âŚ] Outgrowing our resource base is not a phenomenon that began with fossil fuels. [âŚ] In 1796, when [the] world population was about one billion, Robert Thomas Malthus wrote about population growing faster than food production. This was before fossil fuels were widely used. Now, about 230 years later, [the] population has risen to eight billion, thanks to the availability of fossil fuels. We need major innovations, or additional energy resource types, if we want to work around obstacles now."
"The hard fact is that in an age of climate breakdown, human numbers matter. And the ecological impact of another 2-3 billion humans will be immense."
"We must look at the whole man, and at his whole environment. Above all, we must realize that every grain of rice he puts into his mouth, every bit of potato, every piece of meat, and every kernel of corn, must be replaced by another bit from the earthâsomewhere. We must realize that not only does every area have a limited carrying capacityâbut also that this carrying capacity is shrinking and the demand growing. Until this understanding becomes an intrinsic part of our thinking and wields a powerful influence on our formation of national and international policies we are scarcely likely to see in what direction our destiny lies."
"[There's] too many people making too much muck and too much noise with too little space to do it in."
"Today, escalating human populations have vastly exceeded global carrying capacity and now produce massive quantities of solid, liquid, and gaseous waste. Biological diversity is being threatened by over-exploitation, toxic pollution, agricultural mono-culture, invasive species, competition, habitat destruction, urban sprawl, oceanic acidification, ozone depletion, global warming, and climate change. Itâs a runaway train of ecological calamities."
"Homo sapiensâ appetite is gargantuan. As we strive to get at dwindling resources for ever more people, we dig deeper into the Earth, blow the tops of mountains, divert rivers, cut down forests and pave over swaths of land. We fill the land, water, and air with our pollution. Weâre driving record numbers of species to extinction and decimating others with activities from chemical poisoning to hunting for bushmeat, or simply by taking over their habitat. Greenhouse gases from our industry are changing the Earthâs climate, with such dangerous consequences as ocean acidification, rising sea levels and flooding, changes in rainfall patterns including in vital âbreadbaskets,â and loss of forest cover. While the word âsustainableâ has become popular, growing human numbers and activities are anything but. Increasing awareness of our impact has led to developments in renewable energy, recycling, earth-friendly farming and more. There have also been spectacular advances in family planning. But powerfulânotably religiousâopposition has kept governments and international bodies from actively promoting small families and prevented hundreds of millions of women who would plan their families from having access to modern methods. Those who deny that overpopulation is a problem say the poor donât consume much. Yet the poor want nothing more than to consume more, as proved by India and China. Who can blame them? And a burgeoning number of desperately poor people does have a major impact: they cut down forests to grow food, drain rivers, deplete aquifers, and overfish and over-hunt in their local area. But make these points and youâll be accused of blaming the poor for the problems of the rich. We seem bound to learn the hard way that there really is a limit to how many people the Earth can support. We wish it werenât so, but it really is starting to look as if Malthus was right."
"...the gains of low infant and maternal mortality and rises in population longevityâbrought about in great part by harnessing fossil fuels, the agricultural revolution, modernization, and disease and injury reduction effortsâin many instances impedes rather than facilitates moving toward sustainable living. It can be argued from the ecological perspective that most public health efforts, as humanitarian as they are by intention and immediate effect, through accelerating population pressures on the environment are paradoxically hastening the destruction of the earth's habitat on which the next generation of humanity depends. It raises the concern that our perceived gains may be only illusory and temporary, with huge but unmeasured and unlinked environmental costs that will eventually lead to shorter lives of misery for our descendants."
"Agriculture, by overcoming the limitations inherent in the closed system of hunting/gathering, made possible the open-ended expansion of both the population and the means of feeding it. Once it had been adopted, there was no turning back. The more that a civilization farmed, the more it needed extra hands, and so large families were deliberately procreated, which in turn produced still more mouths to feed. Colin Tudge calls it a vicious spiral, Ronald Wright a progress trap."