overpopulation research

Public Health and Overpopulation: The United Nations Takes Action

With the world’s population rising faster than ever before, will our population growth outpace our resource reserves? How can the dangerous effects of overpopulation be managed without diminishing the major improvements in our quality of life that come about thanks to population growth?

The UN projects that over half of the Earth’s population growth in the next three decades will occur in the continent of Africa. This is due to the fact that, from 2010 to 2015, Africa’s population grew at a rate of 2.55 percent annually, with the continent still maintaining the highest pace of population growth among other continents. The UN predicts that, behind Africa, Asia will be the second greatest donor to future international population growth, with an expected addition of approximately one billion people by 2050. In contrast, within every European nation, fertility rates are currently below the population replacement level, which is approximately two children per woman. In most of Europe, fertility rates have remained beneath replacement level for decades. The global population grew fourfold in the past 100 years, so what impact could increased population growth have in the future? Will there be mass-migration? Overcrowding in already densely populated or resource-rich areas? Poor living conditions and sanitation similar to Industrial Revolution era slums?

The global population is currently rising at a steady rate. The number of humans existing on Earth has never been as high as it is now. In 1800, Earth had approximately 1 billion inhabitants, which rose to 2.3 billion in 1940, then 3.7 billion in 1970, and approximately 7.5 billion today. In the last five decades, Earth has experienced an extreme population boom. This phenomenon is known as overpopulation, where the condition in which the amount of humans currently existing on Earth outstrips future resource availability and earth’s carrying capacity. Throughout human history, birth and death rates have always counterbalanced each other, which ensured that Earth had a maintainable population growth level. However, in the 1960s, the global population increased at an unparalleled rate. This brought about a variety of apocalyptic predictions, most prominently, a revival of the Malthusian trap panic.

Paul R. Ehrlich’s 1968 novel, The Population Bomb , eerily echoes Thomas R. Malthus’s landmark 1798 Essay on the Principle of Population . Ehrlich’s novel proposes theories regarding potential outcomes for when agricultural growth does not keep pace with population growth. Ultimately his theories say that the world’s food supply will inevitably become inadequate for feeding the general population, whose numbers would continue to swell until famine, disease epidemics, war, or other calamities took root. These Malthusian predictions about out-of-control population growth have resulted in a variety of detrimental global impacts, particularly the emergence of extreme reproductive control measures, which have taken center stage on an international scale. Today, despite the fact that population scientists mostly agree that Malthus’s forecasts were overblown, the lingering prevalence of these fears have contributed to millions of forced sterilizations in Mexico, Bolivia, Peru, Indonesia, Bangladesh and India, as well as China’s two-child policy . Overall, this has left many wondering whether extreme population growth projections are legitimate or merely groundless panic perpetuated by alarmists.

The Demographic Transition

In reality, rising birth rates and population booms are components of a four-step process called the demographic transition, which the Earth is currently undergoing. Most developed nations have already made this transition, but other countries are currently experiencing this change. In the 1700s, the entire world was undergoing the first stage of the demographic transition. During this time, the continent of Europe was in even poorer condition than the modern-day definition of a developing region, and was afflicted with inferior public health, sustenance, and medical facilities. Birth rates were higher; however, death rates were also higher. For this reason, population growth remained largely stagnant.

Statistically, in the 1700s, women birthed four to six children. However, on average, only two survived to adulthood. When the Industrial Revolution began in Great Britain in the mid-18th century, the Earth experienced the most significant shift in human lifestyles since the Agricultural Revolution. The Industrial Revolution altered every aspect of society, and fostered a greater sense of global interconnectedness. For example, many peasants became factory workers, manufactured products became widely available due to mass production, and countless scientific advancements improved existing methods of transportation, communication, and medicine.

Gradually, this economic development created a middle class and, after the work of union activists, ultimately raised the standard of living and health care for the impoverished labor demographic. Thus began the second transition stage. The increased availability of better foodstuffs, sanitation, and medicine directly contributed to lower death rates, causing a population explosion that doubled Great Britain’s population from 1750 to 1850. In the past, families tended to have more children because not all were expected to survive, but when child mortality rates decreased, the third transition stage was launched. This stage involves reduced conception rates and slowing population growth. Ultimately, a balance was established, with fewer deaths and births, creating a stable population growth rate and signifying the attainment of the fourth and final stage of the demographic transition.

Even as birth rates have decreased dramatically, Earth’s population is still rising at an alarming rate because the humans conceived during the population boom of the 1970s and 1980s are currently having more children; however, the current average number of children per family remains two and a half, while it was five during the late 1970s. As this generation ages and its fertility diminishes, the rate of population growth will likely continue to decrease in every nation. Most of the world’s countries have reached the fourth stage of the demographic transition. In approximately 80 years, developed countries will experience a reduction in fertility from over six children to fewer than three children. Malaysia and South Africa reached this point in 34 years, Bangladesh in 20 years,  and Iran in 10 years. If developing countries are afforded more support, they will reach this point much faster.

Overall, most scientists postulate that human population growth will eventually come to an end, and the UN predicts that Earth’s population will not exceed twelve billion. Some of the major causes of population growth are reduced infant mortality rates, increased lifespans, higher fertility rates, advances in science and technology, and improved access to proper medical care. With the UN’s continued assistance, concurrent with overpopulation, the development level of the global community will increase, and the number of people living in poverty will decrease. Nonetheless, an ever-expanding human population is an immense social and economic challenge that necessitates the alignment of different national interests, especially with regards to reproductive rights, resource availability, and environmental concerns.

The United Nations Takes Action

In 1969, the United Nations Population Fund (UNFPA) was established in order to lead the UN in implementing population programs fundamentally based on the notion of family planning, or the “human right of individuals and couples to freely determine the size of their families” without governmental interference or legislation. In 1994, at the International Conference on Population and Development in Cairo, Egypt, the designated objectives of the UNFPA were determined in greater depth. It was decided that the UNFPA would specifically focus on the gender and human rights elements of population issues; consequently, the UN Population Fund was granted the lead role in aiding nations in fulfilling the Conference’s Programme of Action.

The three most significant sections of the UN Population Fund mandate are “Reproductive Health,” “Gender Equality,” and “Population and Development.” The United Nations Population Division (UNPD) works to confront the interconnected global issues posed by population growth, which is primarily fueled by rising fertility rates, increased longevity, and greater international migration. The UN produces the official demographic approximations and predictions for every country and all regions of the world. The UNFPA specifically addresses global population by compiling data and statistics regarding migration, fertility, marriage, regional development, urbanization, world population projections, and national population policies.

In November 2012, the UNFPA declared family planning a global human right; however, approximately 12 percent of 15 to 49-year-old women internationally are not afforded access to family planning. This is considered an egregious modern-day human rights infringement. The UNFPA aids various UN bodies like the Commission on Population and Development, and endorses the implementation of the Programme of Action undertaken by the International Conference on Population and Development (IPCD) in 1994. The UNFPA has been successful in urging international cooperation on the issue of securing family planning as a human right, pushing the UN to hold three conferences concerning the issue of population, along with two special sessions of the General Assembly and a summit in 2019 .

The Way Forward

Ultimately, apocalyptic population growth fears are overblown, and as such, draconian population control regulations are unnecessary. We have witnessed progress on an international scale in this area, perhaps most notably with China revoking its infamous, longstanding one-child policy just seven years ago. However, a broader global focus on guaranteeing family planning as a human right remains essential. In the words of economist Julian Simon, “Whatever the rate of population growth is, historically it has been that the food supply increases at least as fast, if not faster.” Since Ehrlich’s initial fear-mongering regarding an overpopulation-​induced Armageddon, the planet’s population has more than doubled . However, annually, famine deaths have dropped by millions. Today’s famines are war-induced, not caused by natural resource consumption. As production rose, prices fell and calorie consumption increased, which decreased malnutrition worldwide. In Simon’s words, human ingenuity is the “ ultimate resource .” Therefore, the enactment of heavy-handed population-​control regulations is not only abhorrent, but is also irrational and unsupported by scientific evidence.

Sophia Scott

Sophia Scott is a staff writer for the Harvard International Review. She is interested in global health & health equity, along with the intersections between science and policy.

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October 17, 2013

Human Overpopulation: Still an Issue of Concern?

The jury is still out as to whether the growth of human population is a positive factor or a dominant ill that could spell environmental and social catastrophe

EarthTalk® E - The Environmental Magazine

Dear EarthTalk : Is it true that human overpopulation isn’t such a big issue anymore, as numbers are expected to start declining in a few decades? —Melinda Mason, Boone, Iowa Ever since Thomas Malthus published “An Essay on the Principle of Population” in 1798, positing incorrectly that humans’ proclivity for procreation would exhaust the global food supply within a matter of decades, population growth has been a hot button issue among those contemplating humankind’s future. Indeed our very success going forth and multiplying, paired with our ability to extend our life expectancy, has meant that we are perpetually pushing the limits of the resource base that supports us.

When Malthus was worrying about the planet’s “carrying capacity,” there were only about a billion of us on the planet. Today our population tops seven billion. While better health care and medicine along with advances in food production and access to freshwater and sanitation have allowed us to feed ourselves and stave off many health ills, some so-called Neo-Malthusians believe we may still be heading for some kind of population crash, perhaps triggered or exacerbated by environmental factors related to climate change.

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But others are less concerned given projections that world population will likely start to decline once the world’s less developed nations urbanize and start lowering their birth rates, as has already happened in Europe, the U.S., Australia and parts of Asia. For example, Europe’s “fertility rate” between 2005 and 2010 was just 1.53 live births per woman (the standard replacement rate to maintain a stable population is 2.1). Without immigration, Europe’s population would already be shrinking.

Of course, the immigration that continues to fuel population numbers in developed countries is coming from somewhere. Indeed, population numbers are still growing in many of the world’s developing countries, including the world’s most populous nation, China, and its close rival, India. Also fertility rates in Africa continue to be among the highest in the world, as many countries there are growing fast, too. Poverty and health problems due to poor sanitation, lack of access to food and water, the low social status of women and other ills continue to cripple these regions. Overpopulation could plague us indefinitely if fertility rates don’t drop in these areas, especially as they ramp up their Western-style development. Globally, the United Nations estimates that the number of humans populating the planet in 2100 will range from as few as 6.2 billion—almost a billion less than today—to as many as 15.8 billion on the high end. Meanwhile, other researchers confirm the likelihood of world population levels flattening out and starting to decline by 2100 according to the lower UN estimate. To wit, the Austria-based International Institute for Applied Systems Analysis (IIASA) recently unveiled research showing that if the world stabilizes at a fertility rate comparable to that of many European nations today (roughly 1.5), the global human population will be only half of what it is today by the year 2200, and only one-seventh by 2300.

It is difficult to say which way the global population pendulum will swing in centuries to come, given ever-changing cultural, economic and political attitudes and the development demographics they affect. As such the jury is still out as to whether human overpopulation will become a footnote in history or the dominant ill that stands in the way of all other efforts to achieve sustainability and a kinder, gentler world. CONTACTS : Thomas Malthus, www.esp.org/books/malthus/population/malthus.pdf ; United Nations, www.un.org/esa/population/‎ ; IIASA, http:// webarchive.iiasa.ac.at/Admin/PUB/Documents/IR-08-022.pdf .

EarthTalk® is written and edited by Roddy Scheer and Doug Moss and is a registered trademark of E - The Environmental Magazine www.emagazine.com . Send questions to: [email protected] . Subscribe : www.emagazine.com/subscribe. Free Trial Issue : www.emagazine.com/trial .

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• BOOK REVIEW
• 04 April 2022
• Correction 07 April 2022

Global population is crashing, soaring and moving

• Josie Glausiusz 0

Josie Glausiusz is a science journalist and author in Israel. Twitter: @josiegz

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8 Billion and Counting: How Sex, Death, and Migration Shape Our World Jennifer D. Sciubba W. W. Norton & Company (2022)

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Nature 604 , 33-34 (2022)

doi: https://doi.org/10.1038/d41586-022-00926-6

Updates & Corrections

Correction 07 April 2022 : An earlier version of this book review erroneously stated that one-quarter of the Japanese population was expected to have dementia by 2045. In fact, the proportion refers only to people aged older than 65.

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Epidemics and pandemics: Is human overpopulation the elephant in the room?

N. spernovasilis.

a School of Medicine, University of Crete, Voutes, P.C, 71003 Heraklion, Greece

b “Trifyllio” General Hospital of Kythira, Kythira, Greece

M. Papadakis

c Department of Surgery II, University Hospital Witten-Herdecke, Wuppertal, Germany

C. Tsioutis

d School of Medicine, European University Cyprus, Nicosia, Cyprus

e “Agia Sofia” Children's Hospital, Athens, Greece

Dear Editor,

On the 11th of March 2020 the World Health Organization (WHO) declared the Coronavirus disease 19 (COVID-19) outbreak a global pandemic. Since then, COVID-19 has highlighted the weaknesses of the healthcare systems worldwide as well as the lack of coordination between governments in the face of a global health crisis. It has also emphasised how reluctant citizens can be to follow guidelines and make personal sacrifices for the common good. Now, more than ever, it is evident that action is required to prevent future pandemics by targeting the roots of the problem rather than the problem itself. By analysing this and several other past health crises, it appears that human overpopulation and everything it entails may be the core issue.

Epidemics have ravaged humanity throughout its existence. However, infectious disease outbreaks have been increasing over the last decades [1] . The exponential growth of human population has led to increased urbanization which acts as an accelerant of epidemics, as was the case with COVID-19 in Wuhan. In addition, the continuously increasing pursuit for natural resources has led to the expansion of humans in wild habitats where they are more likely to come into contact with animals that act as reservoirs or vectors of previously unknown infectious agents. Approximately 1.67 million yet-to-be-discovered viral species exist in mammalian and bird hosts and many of these unknown viruses may have zoonotic potential [2] . It is not a coincidence that recent outbreaks such as Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS) and Ebola virus disease, were all zoonotic diseases. According to a report by the WHO, the Ebola outbreak was probably the result of exploitation of a densely forested area in Guinea by timber and mining companies [3] . This allowed fruit bats, which are considered the natural reservoir of the virus, to live in close proximity to humans and thus facilitated the transmission of the virus between the two different species. The loss of biodiversity owing to increased human activity is another factor that seems to contribute to the accelerated spread of infectious diseases. Studies have shown that loss of avian biodiversity in certain regions correlates with an increased incidence of West Nile encephalitis [4] . More specifically, areas with low avian diversity appear to be dominated by species that amplify the virus thus aiding human infection, as opposed to areas with a higher avian diversity that also contain species that are less competent hosts [4] . These examples clearly indicate that the degradation of natural habitats and the destabilization of ecosystems may play a determining role in the development of epidemics and pandemics.

Overpopulation has also generated a rise in food demands. The upsurge of malaria in Borneo eventuated due to the excessive deforestation in order to support the steadily increasing demands for palm oil production through the creation of palm oil plantations [1] . In another example, most of the constantly growing global meat production comes from structures that are called Concentrated Animal Feeding Operations (CAFOs) [5] . In these structures, specific species of animals are tightly packed together and kept in suboptimal conditions. Setting aside issues like animal welfare, CAFOs also constitute the perfect environment for the emergence and spread of infections, including zoonoses [5] . Moreover, the existence of overcrowded live animal markets in many parts of the developing world, where wild and domestic animals are caged in close proximity and are sold for human consumption, poses a significant risk for emerging infectious diseases. Some of these markets in Wuhan have been connected with early cases of COVID-19, although a firm conclusion cannot currently be drawn [6] . In addition, livestock trading across international borders further promotes the spread of infections such as the H5N1 influenza [7] . Finally, the use of antibiotics to compensate for unsanitary conditions and to augment livestock production is a major driving force for the development of drug-resistant bacterial zoonoses [1] .

Cross-border migration which may aid in the spread of infectious diseases is also driven by overpopulation. Most people will migrate in search for labour or better economic prospects due to the increasing stress that population growth exerts on the financial system of their home countries [8] . Others will migrate in order to evade climate change and natural disasters. Finally, disruptions and conflicts that will arise over the exploitation of the earth's finite natural resources will also result in people seeking refuge in other countries [8] .

The human population now is 7.7 billion people and the United Nations estimate that it will rise to 9.7 billion by 2050 [9] . The aforementioned issues are only expected to be exacerbated by this estimation. Perhaps it is time to start addressing the problem of human overpopulation using modest solutions. Taking into account that every year a significant proportion of pregnancies worldwide are unintended [10] , simple actions such as comprehensive sexuality education, improving the status of women in terms of human rights and education and employment opportunities in certain countries, and contraception availability, may all be useful. Also, new methods of contraception that are more easily accessible and effective ought to be sought out. In addition to the proposed measures above, the scale and the nature of the consumption in the developed countries should be modified. The sooner we address these problems and advocate for solutions, the more likely we are to avoid extreme measures like one-child policy, which has been enforced in China in the past, or worse, a catastrophic pandemic that will act as human population's equilibrator.

In conclusion, epidemics and pandemics seem to be fuelled by human overpopulation and the elicited disruption of the balance between humankind and nature. If action is not taken to address the various factors that affect this balance, the COVID-19 pandemic will probably be just the beginning of many more to come.

Human and animal rights

The authors declare that the work described has not involved experimentation on humans or animals.

Informed consent and patient details

The authors declare that the work described does not involve patients or volunteers.

Disclosure of interest

The authors declare that they have no competing interest.

This work did not receive any grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author contributions

All authors attest that they meet the current International Committee of Medical Journal Editors (ICMJE) criteria for Authorship.

Overpopulation: Cause and Effect

Conversations about overpopulation can quickly become controversial because they beg the question: Who exactly is the cause of the problem and what, if anything, should be done about it? Many population experts worry discussions around overpopulation will be abused by small-minded people to suggest some are the “right people” to be on the planet (like themselves), and some people are “the wrong people” (usually people in poverty, people of color, foreigners, and so on—you get the drift). But there are no “right” or “wrong” people on the planet, and discussing the problems of global overpopulation can never be an excuse, or in any way provide a platform, for having that type of conversation.

Each human being has a legitimate claim on a sufficient and fair amount of Earth’s resources. But with a population approaching 8 billion, even if everyone adopted a relatively low material standard of living like the one currently found in Papua New Guinea , it would still push Earth to its ecological breaking point. Unfortunately, the “average person” on Earth consumes at a rate over 50% above a sustainable level. Incredibly, the average person in the United States uses almost five times more than the sustainable yield of the planet.

When we use the term “overpopulation,” we specifically mean a situation in which the Earth cannot regenerate the resources used by the world’s population each year. Experts say this has been the case every year since 1970, with each successive year becoming more and more damaging. To help temper this wildly unsustainable situation, we need to understand what’s contributing to overpopulation and overconsumption and how these trends are affecting everything from climate change to sociopolitical unrest.

Download our free whitepaper

The causes of overpopulation.

Today the Earth is home to over 8 billion people. By 2100 the population is on track to hit 10.8 billion , according to the United Nations — and that’s assuming steady fertility declines in many countries. Interestingly, if extra progress is made in women’s reproductive self-determination, and fertility falls more than the United Nations assumes is likely, the population in 2100 might be a relatively smaller 7.3 billion.

For now, the world’s population is still increasing in huge annual increments (about 80 million per year), and our supply of vital non-renewable resources are being exhausted. Many factors contribute to these unsustainable trends , including falling mortality rates, underutilized contraception, and a lack of education for girls.

Falling Mortality Rate

The primary (and perhaps most obvious) cause of population growth is an imbalance between births and deaths. The infant mortality rate has decreased globally, with 4.1 million infant deaths in 2017 compared to 8.8 million in 1990, according to the World Health Organization (WHO). This is welcome public health news, of course.

At the same time, lifespans are increasing around the world. Those of us who are alive today will likely live much longer than most of our ancestors. Global average life expectancy has more than doubled since 1900 , thanks to advancements in medicine, technology, and general hygiene. Falling mortality rates are certainly nothing to complain about either, but widespread longevity does contribute to the mathematics of increasing population numbers.

Underutilized Contraception 

The global fertility rate has fallen steadily over the years, down from an average of 5 children per woman in 1950 to 2.4 children per woman today, according to the UN Population Division . Along with that promising trend, contraceptive use has slowly but steadily increased globally, rising from 54% in 1990 to 57.4% in 2015. Yet, on the whole, contraceptive use is still underutilized. For example, according to the WHO, an estimated 214 million women in developing countries who want to avoid pregnancy are not using modern contraceptives.

These women aren’t using contraceptives for a variety of reasons, including social norms or religious beliefs that discourage birth control, misconceptions about adverse side effects, and a lack of agency for women to make decisions around sex and family planning. An estimated 44% of pregnancies were unintended worldwide between 2010-2014. Getting more women the access and agency to utilize family planning methods could go a long way in flattening the population curve.

Lack of Female Education    

Although female access to education has increased over the years, the gender gap remains. Roughly 130 million girls worldwide are out of school currently, and an estimated 15 million girls of primary school age will never   learn to read and write, compared with 10 million boys.

Increasing and encouraging education among women and girls can have a number of positive ripple effects, including delayed childbearing , healthier children, and an increase in workforce participation. Plenty of evidence suggests a negative correlation between female education and fertility rates.

If increased female education can delay or decrease fertility and provide girls with opportunities beyond an early marriage, it could also help to mitigate current population trends. 

The Effects of Overpopulation

It is only logical that an increase in the world’s population will cause additional strains on resources. More people means an increased demand for food, water, housing, energy, healthcare, transportation, and more. And all that consumption contributes to ecological degradation, increased conflicts, and a higher risk of large-scale disasters like pandemics.  

Ecological Degradation 

An increase in population will inevitably create pressures leading to more deforestation, decreased biodiversity, and spikes in pollution and emissions, which will exacerbate climate change . Ultimately, unless we take action to help minimize further population growth heading into the remainder of this century, many scientists believe the additional stress on the planet will lead to ecological disruption and collapse so severe it threatens the viability of life on Earth as we know it. 

Each spike in the global population has a measurable impact on the planet’s health. According to estimates in a study by Wynes and Nicholas (2017) , a family having one fewer child could reduce emissions by 58.6 tonnes CO2-equivalent per year in developed countries.

Increased Conflicts 

The scarcity brought about by environmental disruption and overpopulation has the potential to trigger an increase in violence and political unrest. We’re already seeing wars fought over water, land, and energy resources in the Middle East and other regions, and the turmoil is likely to increase as the global population grows even larger.

Higher Risk of Disasters and Pandemics 

Many of the recent novel pathogens that have devastated humans around the world, including COVID-19, Zika virus, Ebola, and West Nile virus, originated in animals or insects before passing to humans. Part of the reason the world is entering “ a period of increased outbreak activity ” is because humans are destroying wildlife habitats and coming into contact with wild animals on a more regular basis. Now that we’re in the midst of a pandemic, it has become clear how difficult it is to social distance in a world occupied by nearly 8 billion people.   

Discover the real causes and effects of overpopulation

What can be done about overpopulation.

When addressing overpopulation, it’s crucial to take an approach of providing empowerment while mobilizing against anybody advocating for the use of coercion or violence to solve our problems. The combined efforts of spreading knowledge about family planning, increasing agency among women , and debunking widely held myths about contraception will measurably change the trajectory of the world’s population.

As we carry out our work at Population Media Center (PMC), we see first-hand that spreading awareness about family planning methods and the ecological and economic benefits of having smaller families can change reproductive behavior. For example, listeners of our Burundian radio show Agashi (“Hey! Look Again!”) were 1.7 times more likely than non-listeners to confirm that they were willing to negotiate condom use with a sexual partner and 1.8 times more likely than non-listeners to say that they generally approve of family planning for limiting the number of children.

CELEBRATING EARTH DAY WITH CONVERSATIONS ON OVERPOPULATION

In the spirit of Earth Day, it’s crucial to approach discussions about overpopulation with sensitivity and inclusivity. Overpopulation conversations should focus on the collective responsibility to steward Earth’s resources sustainably, rather than assigning blame or dividing communities. By fostering understanding and promoting access to education and reproductive health services, we can work towards a more equitable and sustainable future for all.

At PMC we harness the power of storytelling to empower listeners to live healthier and more prosperous lives, which in turn contributes to stabilizing the global population so that people can live sustainably with the world’s renewable resources. Discover how PMC is taking action against overpopulation today!

We’re Focused on Making an Impact. Learn More About Our Work.

Global sustainability.

Women’s Rights

More Readings

How do overpopulation and overconsumption damage the environment what you need to know.

How Is Population Growth Responsible for the Growing Problem of Water Scarcity

What lies ahead after the world’s population reaches 8 billion , how does overpopulation affect the economy, join us in promoting the equitable, sustainable world we’re all fighting for, one action at a time..

Population Growth

Population growth is one of the most important topics we cover at Our World in Data .

For most of human history, the global population was a tiny fraction of what it is today. Over the last few centuries, the human population has gone through an extraordinary change. In 1800, there were one billion people. Today there are more than 8 billion of us.

But after a period of very fast population growth, demographers expect the world population to peak by the end of this century.

On this page, you will find all of our data, charts, and writing on changes in population growth. This includes how populations are distributed worldwide, how this has changed, and what demographers expect for the future.

Related topics

• Child Mortality
• Fertility Rate
• Life Expectancy
• Age Structure

Key insights on Population Growth

Population cartograms show us where the world’s people are.

Geographical maps show us where the world’s landmasses are; not where people are. That means they don’t always give us an accurate picture of how global living standards are changing.

One way to understand the distribution of people worldwide is to redraw the world map – not based on the area but according to population.

This is shown here as a population cartogram : a geographical presentation of the world where the size of countries is not drawn according to the distribution of land but by the distribution of people. It’s shown for the year 2018.

As the population size rather than the territory is shown in this map, you can see some significant differences when you compare it to the standard geographical map we’re most familiar with. 

Small countries with a high population density increase in size in this cartogram relative to the world maps we are used to – look at Bangladesh, Taiwan, or the Netherlands. Large countries with a small population shrink in size – look for Canada, Mongolia, Australia, or Russia.

You can find more details on this cartogram in our article about it:

What you should know about this data

• This map is based on the United Nation’s 2017 World Population Prospects report. Our interactive charts show population data from the most recent UN revision. This means there may be minor differences between the figures shown on the map and the latest estimates in our other charts.

The world population has increased rapidly over the last few centuries

The speed of global population growth over the last few centuries has been staggering. For most of human history, the world population was well under one million. 1

As recently as 12,000 years ago, there were only 4 million people worldwide.

The chart shows the rapid increase in the global population since 1700. 

The one-billion mark wasn’t broken until the early 1800s. It was only a century ago that there were 2 billion people.

Since then, the global population has quadrupled to eight billion.

Around 108 billion people have ever lived on our planet. This means that today’s population size makes up 6.5% of the total number of people ever born. 2

This increase has been the result of advances in living conditions and health that reduced death rates – especially in children – and increases in life expectancy.

• This data comes from a combination of sources, all detailed in our sources article for our long-term population dataset.

Population growth is no longer exponential – it peaked decades ago

There’s a popular misconception that the global population is growing exponentially. But it’s not.

While the global population is still increasing in absolute numbers, population growth peaked decades ago.

In the chart, we see the global population growth rate per year. This is based on historical UN estimates and its medium projection to 2100.

Global population growth peaked in the 1960s at over 2% per year. Since then, rates have more than halved, falling to less than 1%. 

The UN expects rates to continue to fall until the end of the century. In fact, towards the end of the century, it projects negative growth, meaning the global population will shrink instead of grow.

Global population growth, in absolute terms – which is the number of births minus the number of deaths – has also peaked. You can see this in our interactive chart:

The world has passed “peak child”

Hans Rosling famously coined the term “ peak child ” for the moment in global demographic history when the number of children stopped increasing.

According to the UN data, the world has passed “peak child”, which is defined as the number of children under the age of five.

The chart shows the UN’s historical estimates and projections of the number of children under five.

It estimates that the number of children in the world peaked in 2017. For the coming decades, demographers expect a decades-long plateau before the number will decline more rapidly in the second half of the century.

• These projections are sensitive to the assumptions made about future fertility rates worldwide. Find out more from the UN World Population Division .
• Other sources and scenarios in the UN’s projections suggest that the peak was reached slightly earlier or later. However, most indicate that the world is close to “peak child” and the number of children will not increase in the coming decades.
• The ‘ups and downs’ in this chart reflect generational effects and ‘baby booms’ when there are large cohorts of women of reproductive age, and high fertility rates. The timing of these transitions varies across the world.

The UN expects the global population to peak by the end of the century

When will population growth come to an end?

The UN’s historical estimates and latest projections for the global population are shown in the chart.

The UN projects that the global population will peak before the end of the century – in 2086, at just over 10.4 billion people.

• These projections are sensitive to the assumptions made about future fertility and mortality rates worldwide. Find out more from the UN World Population Division .
• Other sources and scenarios in the UN’s projections can produce a slightly earlier or later peak. Most demographers, however, expect that by the end of the century, the global population will have peaked or slowed so much that population growth will be small.

Explore data on Population Growth

Research & writing.

What would the work look like if each country’s area was in proportion to its population?

The world population has increased rapidly in recent centuries. But this is slowing.

Max Roser and Hannah Ritchie

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A crowded street in Calcutta, India, reflects the looming threat of overpopulation, which will further strain resources already in limited supply.

As World’s Population Booms, Will Its Resources Be Enough for Us?

New projections of escalating growth increase the tension between humanity’s expanding needs and what the planet can provide.

There are more than 7 billion people on Earth now, and roughly one in eight of us doesn't have enough to eat. The question of how many people the Earth can support is a long-standing one that becomes more intense as the world's population—and our use of natural resources—keeps booming.

This week, two conflicting projections of the world's future population were released. As   National Geographic's   Rob Kunzig   writes here , a new United Nations and University of Washington   study in the journal Science says it's highly likely we'll see 9.6 billion Earthlings by 2050, and up to 11 billion or more by 2100. These researchers used a new "probabalistic" statistical method that establishes a specific range of uncertainty around their results. Another study in the journal   Global Environmental Change projects that   the global   population will peak at 9.4 billion later this century and fall below 9 billion by 2100, based on a survey of population experts. Who is right? We'll know in a hundred years.

Population debates like this are why, in 2011, National Geographic published a series called "7 Billion" on   world population , its trends, implications, and future. After years of examining global environmental issues such as   climate change ,   energy ,   food supply , and   freshwater , we thought the time was ripe for a deep discussion of people and how we are connected to all these other issues—issues that are getting increased attention today, amid the new population projections.

After all, how many of us   there are,   how many children we have, how long we live, and where and how we live affect virtually every aspect of   the planet upon which   we rely to survive: the land, oceans, fisheries, forests, wildlife, grasslands, rivers and lakes, groundwater, air quality, atmosphere, weather, and climate.

World population passed 7 billion on October 31, 2011,   according to the United Nations . Just who the 7 billionth person was and where he or she was born   remain a mystery ; there is no actual cadre of   census takers who go house to house in every country, counting people.Instead,   population estimates are made by most national governments and international organizations such as the UN. These estimates are based on assumptions about existing population size and expectations of fertility, mortality, and migration in a geographic area.

We've been on a big growth spurt during the past century or so. In 1900, demographers had the world's population at 1.6 billion, in 1950 it was about 2.5 billion, by 2000 it was more than 6 billion. Now, there are about 7.2 billion of us.

For Hungry Minds

In recent years we've been adding about a billion people every 12 or 13 years or so. Precisely how many of us are here right now is also a matter of debate, depending on whom you consult: The United Nations offers a range of current population figures and trends, the   U.S. Census Bureau has its own estimate, and the   Population Reference Bureau also tracks us.

The new UN study out this week projects that the world's population growth may not stop any time soon. That is a reversal from estimates done five years ago, when   demographers—people who study population trends—were projecting that   by 2045, world population likely would reach about 9 billion and begin to level off soon after.

But now, the UN researchers who published these new projections in the journal   Science say that a flattening of population growth is not going to happen soon without rapid fertility declines—or a reduction in the number of children per mother—in most parts of sub-Saharan Africa that are still experiencing rapid population growth. As Rob Kunzig wrote for National Geographic, the new study estimates that "there's an 80 percent chance . . . that the actual number of people in 2100 will be somewhere between 9.6 and 12.3 billion."

A History of Debates Over Population

In a famous 1798 essay,   the Reverend Thomas Malthus proposed that human population would grow more rapidly than our ability to grow food, and that eventually we would starve.

He asserted that the population would grow geometrically—1, 2, 4, 8, 16, 32—and that food production would increase only arithmetically—1, 2, 3, 4, 5, 6. So food production would not keep up with our expanding appetites. You might imagine Malthus' scenario on geometric population growth as being   like compound interest :   A couple have two children and those children each produce two children. Those four children produce two children each tomake   eight, and those eight children each have their own two kids, leaving 16 kids in that generation. But worldwide, the current median fertility rate is about 2.5, (or five children between two couples) so, like compound interest, the population numbers can rise even faster.

Even though   more than 800 million people worldwide don’t have enough to eat now , the mass starvation Mathus envisioned hasn't happened. This is primarily because advances in agriculture—including   improved plant breeding and the use of   chemical fertilizers —have kept global harvests increasing fast enough to mostly keep up with demand. Still,   researchers such as   Jeffrey Sachs and Paul Ehrlich continue to worry that Malthus eventually might be right.

Ehrlich, a   Stanford University population biologist, wrote a 1968 bestseller called   The Population Bomb , which warned of mass starvation in the 1970s and 1980s because of overpopulation. Even though he drastically missing that forecast, he continues to argue that   humanity is heading for calamity .   Ehrlich says the key issue now is not just the number of people on Earth, but a dramatic rise in our recent consumption of natural resources, which Elizabeth Kolbert explored in 2011 in an article called   "The Anthropocene — The Age of Man."

As part of this   human-dominated era, the past half century also has been referred to as a period of   "Great Acceleration" by   Will Steffen at   International Geosphere-Biosphere Program. Besides a nearly tripling of human population since the end of World War II, our presence has been marked by a dramatic increase in human activity—the damming of rivers, soaring water use, expansion of cropland, increased use of irrigation and fertilizers, a loss of forests, and more motor vehicles. There also has been a sharp rise in the use of coal, oil, and gas, and a rapid increase in the atmosphere of methane and carbon dioxide, greenhouse gases that result from changes in land use and the burning of such fuels.

Measuring Our Rising Impact

As a result of this massive expansion of our presence on Earth, scientists Ehrlich, John Holdren, and Barry Commoner in the early 1970s devised   a formula to measure our rising impact, called IPAT, in which (I)mpact equals (P)opulation multiplied by (A)ffluence multiplied by (T)echnology.

The IPAT formula, they said, can help us realize that our cumulative impact on the planet is not just in population numbers, but also in the increasing amount of natural resources each person uses.   The graphic   above, which visualizes IPAT, shows that the rise in our cumulative impact since 1950—rising population combined with our expanding demand for resources—has been profound.

IPAT is a useful reminder that population, consumption, and technology all help shape our environmental impact, but it shouldn’t be taken too literally. University of California   ecologist John Harte has said that IPAT ". . . conveys the notion that population is a linear multiplier. . . . In reality, population plays a much more dynamic and complex role in shaping environmental quality."

One of our biggest impacts is agriculture. Whether we can grow enough food sustainably for an expanding world population also presents an urgent challenge, and this becomes only more so in light of these new population projections. Where will food for an additional 2 to 3 billion people come from when we are already barely keeping up with 7 billion? Such questions underpin a 2014   National Geographic series on   the future of food .

As climate change damages crop yields and   extreme weather disrupts harvests , growing enough food for our expanding population has become what The 2014 World Food Prize Symposium calls " the greatest challenge in human history ."

Population's Structure: Fertility, Mortality and Migration

Immigrant women at a Sikh festival in Spain. Research suggests that the more education a woman receives, the fewer children she is likely to have.

Population is not just about numbers of people. Demographers typically focus on three dimensions— fertility, mortality, and migration —when examining population trends. Fertility examines how many children a woman bears in her lifetime, mortality looks at how long we live, and migration focuses on where we live and move. Each of these population qualities influences the nature of our presence and impact across the planet.

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The newly reported higher world population projections result from   continuing high fertility in sub-Saharan Africa .   The median number of children per woman in the region remains at 4.6, well above both the global mean of 2.5 and the replacement level of 2.1. Since 1970, a global decline in fertility— from about 5 children per woman to about 2.5 —has occurred across most of the world: Fewer babies have been born, family size has shrunk, and population growth has slowed. In the United States,   fertility is now slightly below replacement level .

Reducing fertility is essential if future population growth is to be reined in.   Cynthia Gorney wrote about the dramatic story of declining Brazilian fertility as part of   National Geographic's 7 Billion series. Average family size dropped   from 6.3 children to 1.9 children per woman over two generations in Brazil, the   result of improving education for girls, more career opportunities, and the increased availability of contraception.

Mortality —or birth rates versus death rates—and   migration (where we live and move) also affect the structure of population. Living longer can cause a region’s population to increase even if birth rates remain constant. Youthful nations in the Middle East and Africa, where there are more young people than old, struggle to provide sufficient   land, food, water, housing, education, and employment for young people. Besides the search for a life with more opportunity elsewhere,   migration also is driven by the need to escape political disruption or declining environmental conditions such as chronic drought and food shortages.

A paradox of lower fertility and reduced population growth rates is that as education and affluence improves,   consumption of natural resources increases per person . In other words, (as illustrated in the IPAT graphic here) as we get richer, each of us consumes more natural resources and energy, typically carbon-based fuels such as coal, oil, and gas. This can be seen in consumption patterns that include higher protein foods such as meat and dairy, more consumer goods, bigger houses, more vehicles, and more air travel.

When it comes to natural resources, studies indicate we are living beyond our means. An ongoing   Global Footprint Network study says we now use the equivalent of 1.5 planets to provide the resources we use, and to absorb our waste. A study by the Stockholm Resilience Institute has identified a set of   "nine planetary boundaries" for conditions in which we could live and thrive for generations, but it shows that we already have exceeded the institute's boundaries for   biodiversity loss, nitrogen pollution, and climate change .

Those of us reading this article are among an elite crowd of Earthlings. We have reliable electricity, access to Internet-connected computers and phones, and time available to contemplate these issues.

About   one-fifth of those on Earth still don't have have access to reliable electricity . So as we debate population, things we take for granted—reliable lighting and cooking facilities, for example—remain beyond the reach of about 1.3 billion or more people. Lifting people from the darkness of   energy poverty could help improve lives.

Children read the Koran using flashlights in Wantugu, Ghana. Eliminating energy poverty could help education rates, which by extension could help rein in overpopulation.

As World Bank Vice President   Rachel Kyte told Marianne Lavelle of National Geographic last year, "It is energy that lights the lamp that lets you do your homework, that keeps the heat on in a hospital, that lights the small businesses where most people work. Without energy, there is no economic growth, there is no dynamism, and there is no opportunity."

Improved education, especially for girls ,   is cited as a key driver of declining family size. Having light at night can become a gateway to better education for millions of young people and the realization that opportunities and choices besides bearing many children can await.

So when we debate population, it's important to also discuss the impact—the how we live—of the population equation. While new projections of even higher world population in the decades ahead are cause for concern, we should be equally concerned about—and be willing to address—the increasing effects of resource consumption and its waste.

Dennis Dimick led creation of the 2011 National Geographic series "7 Billion," and is National Geographic's executive editor for the Environment. You can follow him on Twitter, Instagram , and flickr.

Related Reading and Resources

National Geographic 7 Billion Series 2011

United Nations World Population Trends

2014 Population Data Sheet from Population Reference Bureau

Population Reference Bureau Interactive World Population Map

Grist: Hungry, Hungry Humans Series

Global Post: Half the World’s Population Lives in these six countries

Pew Fact Tank 10 projections for world population in 2050

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Articles on Overpopulation

Displaying 1 - 20 of 45 articles.

Population can’t be ignored. It has to be part of the policy solution to our world’s problems

Jenny Stewart , UNSW Sydney

Thinking of having a baby as the planet collapses? First, ask yourself 5 big ethical questions

Craig Stanbury , Monash University

Global population hits 8 billion, but per-capita consumption is still the main problem

Lorenzo Fioramonti , University of Surrey ; Ida Kubiszewski , UCL ; Paul Sutton , University of Denver , and Robert Costanza , UCL

You are now one of 8 billion humans alive today. Let’s talk overpopulation – and why low income countries aren’t the issue

Matthew Selinske , RMIT University ; Leejiah Dorward , Bangor University ; Paul Barnes , UCL , and Stephanie Brittain , University of Oxford

8 billion people: why trying to control the population is often futile – and harmful

Melanie Channon , University of Bath and Jasmine Fledderjohann , Lancaster University

More than 1 in 5 US adults don’t want children

Zachary P. Neal , Michigan State University and Jennifer Watling Neal , Michigan State University

What the controversial 1972 ‘Limits to Growth’ report got right: Our choices today shape future conditions for life on Earth

Matthew E. Kahn , USC Dornsife College of Letters, Arts and Sciences

Curb population growth to tackle climate change: now that’s a tough ask

Michael P. Cameron , University of Waikato

Worried about Earth’s future? Well, the outlook is worse than even scientists can grasp

Corey J. A. Bradshaw , Flinders University ; Daniel T. Blumstein , University of California, Los Angeles , and Paul Ehrlich , Stanford University

Bob Brown is right – it’s time environmentalists talked about the population problem

Colin D. Butler , Australian National University

Beware far-right arguments disguised as environmentalism

Marc Hudson , Keele University

Why we should be wary of blaming ‘overpopulation’ for the climate crisis

Heather Alberro , Nottingham Trent University

Pasha 45: Spotlight on population growth in Africa

Ozayr Patel, The Conversation

Stabilising the global population is not a solution to the climate emergency – but we should do it anyway

Mark Maslin , UCL

Want to live longer? Consider the ethics

John K. Davis , California State University, Fullerton

Here’s what a population policy for Australia could look like

Liz Allen , Australian National University

‘Overpopulation’ and the environment: three ideas on how to discuss it in a sensitive way

Rebecca Laycock Pedersen , Keele University and David P. M. Lam , Leuphana University

Australia could house around 900,000 more migrants if we no longer let in tourists

Raja Junankar , UNSW Sydney

Making small cities bigger will help better distribute Australia’s 25 million people

Glen Searle , University of Sydney

A long fuse: ‘The Population Bomb’ is still ticking 50 years after its publication

Derek Hoff , University of Utah

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• Climate change
• Consumption
• Family planning
• Global population
• Population control
• Population growth
• Sustainability

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Overpopulation and urban sustainable development—population carrying capacity in Shanghai based on probability-satisfaction evaluation method

• Published: 16 April 2020
• Volume 23 , pages 3318–3337, ( 2021 )

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• Yingying Zhang 1 ,
• Yigang Wei 1 , 2 &
• Jian Zhang 3  

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With the rapid and widespread urbanization, a large number of people pour into cities, which bring a series of urban diseases and directly threaten the sustainable development of the destination city. It is particularly important to reasonably measure the population carrying capacity to promote the sustainable development of cities. Therefore, based on Shanghai’s municipal data from 1985 to 2017, this paper used the probability-satisfaction method to predict the urban population carrying capacity of Shanghai in 2020. Several important findings are derived: First, there is a general pattern that the urban population carrying capacity increases as the probability-satisfaction level decreases; second, the sensitive degrees of the population carrying capacity of different constraining factors vary. The sensitive degrees of the city’s GDP, fiscal revenues and paved road areas are lower than those of other constraining factors; third, currently the number of medical practitioners, the paved road areas and the volume of waste emission are the three most important constraining factors in Shanghai. Fourth, results of the multifactor analysis reveal that when the probability-satisfaction level is equal to the ideal level, the overall population carrying capacity of Shanghai is between 17.55 million and 23.52 million; when the probability-satisfaction level research the acceptable level, the overall population carrying capacity of Shanghai is between 20.35 million and 30.12 million people. Therefore, by 2020, the Shanghai government needs to formulate well-considering population management plan according to actual resources conditions in order to achieve balanced and sustainable urban development.

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City Health Examination in China: A Methodology and Empirical Study

Rural population’s preferences matter: a value set for the EQ-5D-3L health states for China’s rural population

Mediating effects between objective and subjective indicators of urban quality of life: testing specific models for safety and access.

Botkin, D. B., & Beveridge, C. E. (1997). Cities as environments. Urban Ecosystems, 1, 3–9.

Google Scholar  

Campbell, D. E. (1998). Emergy analysis of human carrying capacity and regional sustainability: An example using the state of maine. Environmental Monitoring and Assessment, 51 (1–2), 531–569.

Fang, W., An, H., Li, H., Gao, X., & Sun, X. (2017). Urban economy development and ecological carrying capacity: Taking Beijing city as the case. Energy Procedia , 105 , 3493–3498.

FAO. (1982). Potential population supporting capacities of lands in developing world . Rome: Food and Agriculture Organization of the United Nations.

Feng, Z. M., & Li, P. (2018). Origin and development of the concept of bearing capacity: Discussions from the perspective of resources and environment. Journal of Natural Resources, 33 (09), 1475–1489. (in Chinese) .

Guan, H. W., & Du, W. (2016). Research on urban population carrying capacity with possibility and satisfiability method. Decision Reference, 14 (02), 47–50. (in Chinese) .

Guo, Z., Wu, Z., Schimmele, C. M., & Li, S. Z. (2012). The effect of urbanization on China’s fertility. Population Research and Policy Review, 31 (3), 417–434.

Hassan, A. M., & Lee, H. (2015). The paradox of the sustainable city: Definitions and examples. Environment, Development and Sustainability, 17 (06), 1267–1285.

Huang, W., Wang, H., Zhao, H. R., & Wei, Y*. (2019). The temporal-spatial characteristics and key influencing factors of PM 2.5 concentrations in China: Based on a largely expanded list of potential influencing factors. Environmental Engineering and Management Journal , 18 (12), 2587–2604.

Jiang, M., & Li, H. J. (2016). Evaluation model of regional water carrying capacity in shale gas development based on system dynamics method. Resources & Industries, 18 (06), 33–39. (in Chinese) .

Li, W., Indrawati, S. M., Liu, S. J., Han, J., Rohland, K., Hofman, B., et al. (2014). China: Promoting efficient, inclusive and sustainable urbanization. Management World, 04, 5–41. (in Chinese) .

Li, W. L., & Ren, Y. (2017). Research on system dynamics simulation model urban comprehensive carrying capacity. Ecological Economy, 33 (02), 78–80. (in Chinese) .

Lin, S. F., Sun, J., Marinova, D., & Zhao, D. T. (2017). Effects of population and land urbanization on China’s environmental impact: Empirical analysis based on the extended STIRPAT model. Sustainability, 9 (5), 825.

Liu, H. M. (2012). Comprehensive carrying capacity of the urban agglomeration in the Yangtze River Delta, China. Habitat International, 36 (4), 462–470.

Liu, F. Y. (2014). The role of rational allocation of water resources in the region by water supply and demand balance analysis-take Puyang City as an example. China Mining Magazine, z1, 112–115. (in Chinese) .

Meadows, D., et al. (1972). The Limit to Growth . Washington: D.C., Potomac.

Millington, R., & Gifford, R. (1973). Energy and how we live, Australian UNESCO Seminar, Committee for Man and Biosphere.

National Bureau of Statistics. (2017). China statistical yearbook . Beijing: China Statistical Publishing House.

Ning, J., Liu, J. Y., Shao, Q. Q., & Fan, J. W. (2014). Multiply scenario simulations of environmental carrying capacity in the western region of China. China Population, Resources and Environment, 24 (11), 136–146. (in Chinese) .

Odum, H. T. (1996). Environmental accounting: Energy and environmental decision making . New York: Wiley.

Onishi, T. (1994). A capacity approach for sustainable urban development: An empirical study. Regional Studies, 28 (1), 39–51.

Shanghai Bureau of Statistics. (2017). Shanghai statistical yearbook . Beijing: China Statistical Publishing House.

Shi, Y., Wang, H., & Yin, C. (2013a). Evaluation method of urban land population carrying capacity based on gis—A case of Shanghai, China. Computers, Environment and Urban Systems, 39 (3), 27–38.

CAS   Google Scholar  

Shi, Y. S., Yin, C. Y., Wang, H. F., & Tan, W. K. (2013b). Research progress and prospect on urban comprehensive carrying capacity. Geographical Research, 32 (1), 133–145. (In Chinese) .

Sun, Q., Zhang, X. H., Zhang, H. W., & Niu, H. P. (2018). Coordinated development of a coupled social economy and resource environment system: A case study in Henan Province, China. Environment, Development and Sustainability, 20 (3), 1385–1404.

Taagepera, R. (2014). A world population growth model: Interaction with earth’s carrying capacity and technology in limited space. Technological Forecasting and Social Change, 82, 34–41.

Tian, Y., & Sun, C. (2018). Comprehensive carrying capacity, economic growth and the sustainable development of urban areas: A case study of the Yangtze river economic belt. Journal of Cleaner Production, 195, 486–496.

Tong, Y. F., & Liu, G. J. (2011). Research on urban population carrying capacity with possibility and satisfiability method: A case study in Beijng, China. Jilin University Journal Social Sciences Edition, 51 (01), 152–157. (in Chinese) .

Tsai, I. C. (2018). Housing price convergence, transportation infrastructure and dynamic regional population relocation. Habitat International, 79, 61–73.

UNESCO and FAO. (1985). Carrying capacity assessment with a pilot study of Kenya: A resource accounting methodology for exploring national options for sustainable development; UNESCO: Paris, France; FAO: Rome, Italy.

Wackernagel, M., & Rees, W. E. (1997). Perceptual and structural barriers to investing in natural capital: Economics from an ecological footprint perspective. Ecological Economics, 20 (1), 3–24.

Wang, H. C. (1982). Adopt the multi-objective decision-making method of possibility and satisfaction. Systems Engineering Theory and Practice, 2 (1), 14–22. (in Chinese) .

Wei, Y. G., Huang, C., Lam, P., & Patrick, T. I. (2015a). Using urban-carrying capacity as a benchmark for sustainable urban development: An empirical study of Beijing. Sustainability, 7, 3244–3268.

Wei, Y., Huang, C., Lam, P. T. I., & Yuan, Z. (2015b). Sustainable urban development: A review on urban carrying capacity assessment. Habitat International, 46, 64–71.

Wei, Y. G., Huang*, C., Li, J., & Xie, L. L. (2016). An evaluation model for urban carrying capacity: A case study of China’s mega-cities. Habitat International, 53, 87–96.

Wei, Y. G., Li, Y., Liu, X. J., & Wu, M. (2019a). Sustainable development and green GDP assessments in mega-cities based on the emergy analysis method—A case study of Wuhan. Sustainable Development , 1–14.

Wei, Y., Li, Y., Wu, M., & Li, Y. (2019b). Progressing sustainable development of ‘the Belt and Road countries’: Estimating environmental efficiency based on the super-SBM model. Sustainable Development , 1–19.

Wei, Y., Wu, M., Li*, Y., & Li, Y. (2019c). The decomposition of total-factor CO2 emission efficiency of 97 contracting countries in Paris Agreement. Energy Economics, 78, 365–378.

Wei, Y., Zhu, X., Li, Y., Yao, Y., & Tao, Y. (2019d). Influential factors of national and regional CO2 emission in China based on combined model of DPSIR and PLS-SEM. Journal of Cleaner Production, 212, 698–712.

William, E. R. (1992). Ecological footprints and appropriated carrying capacity: What urban economics leaves out. Environment & Urbanization, 4 (2), 121–130.

Wu, X., Lai, G. Y., & Wang, H. Q. (2018). Research on climate carrying capacity evaluation of Nanchang City. Jiang Xi Science, 36 (04), 615–618. (in Chinese) .

Wu, M., Wei, Y., Lam, P. T. I., Liu, F., & Li, Y. (2019). Is urban development ecologically sustainable? Ecological footprint analysis and prediction based on a modified artificial neural network model: A case study of Tianjin in China. Journal of Cleaner Production, 237, 117795.

Xiang, Y. B., Xie, B. G., & Deng, C. X. (2013). Research on population capacity of Hunan Province by P–S model. Northwest Population, 34 (03), 53–56. (in Chinese) .

Xiao, Y. P., Song, Y., & Wu, X. D. (2018). How far has China’s urbanization gone? Sustainability, 10, 2953.

Yang, N. N., Li, J. S., Lu, B. B., Luo, M. H., & Li, L. Z. (2019). Exploring the spatial pattern and influencing factors of land carrying capacity in Wuhan. Sustainability, 11 (10), 2786.

Zhang, Y., Yang, Z. F., & Yu, X. Y. (2006). Measurement and evaluation of interactions in complex urban ecosystem. Ecological Modeling, 196, 77–89.

Zhu, X., Li, Y., Zhang, P., Wei*, Y., Zheng, X., & Xie, L. L. (2019a). Temporal-spatial characteristics of urban land use efficiency of China’s 35 mega cites based on DEA: Decomposing technology and scale efficiency. Land Use Policy, 88, 104083.

Zhu, X., Wei*, Y., Lai, Y., Li, Y., Zhong, S., & Dai, C. (2019b). Empirical analysis of the driving factors of China’s ‘land finance’ mechanism using soft budget constraint theory and the PLS-SEM model. Sustainability, 11 (3), 742.

Zhu, Y. Z., Xia, J., & Wang, G. S. (2005). Assessment of water resources carrying-capacity with multi-criteria scenario analysis method: A case study in Zhangye region. Geographical Research, 24 (05), 732–740. (In Chinese) .

Zhu, X., Zhang, Z., Wei*, Y., Li, Y., & Zhao, H. (2019c). Measuring the efficiency and driving factors of urban land use based on the DEA method and the PLS-SEM model: A case study of 35 large and medium-sized cities in China. Sustainable Cities and Society, 50, 101646.

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Acknowledgements

The authors are grateful for the financial support from the National Natural Science Foundation of China under Grant (No. 71904009), MOE (Ministry of Education in China) Project of Humanities and Social Sciences (No. 18YJC840041) and the First-class Discipline Construction Project of Central University of Finance and Economics “Research on Innovation of Public Sector Strategy and Performance Management Theory in the New Era” (No. CUFE2019-005). Besides, the authors would like to thank the anonymous reviewers for insightful comments that helped us improve the quality of the paper.

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Zhang, Y., Wei, Y. & Zhang, J. Overpopulation and urban sustainable development—population carrying capacity in Shanghai based on probability-satisfaction evaluation method. Environ Dev Sustain 23 , 3318–3337 (2021). https://doi.org/10.1007/s10668-020-00720-2

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Overpopulation and the impact on the environment.

Doris Baus , The Graduate Center, City University of New York Follow

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Liberal Studies

Sophia Perdikaris

Subject Categories

Agricultural and Resource Economics | Demography, Population, and Ecology | Economics | Education Policy | Environmental Policy | Environmental Studies | Family, Life Course, and Society | Growth and Development | Health Economics | Health Policy | International and Area Studies | International Relations | Place and Environment | Politics and Social Change | Social and Behavioral Sciences | Urban Studies | Urban Studies and Planning

overpopulation, environmental impact, malthus, population growth, environmental issues, causes of overpopulation

In this research paper, the main focus is on the issue of overpopulation and its impact on the environment. The growing size of the global population is not an issue that appeared within the past couple of decades, but its origins come from the prehistoric time and extend to the very present day. Throughout the history, acknowledged scientists introduced the concept of “overpopulation” and predicted the future consequences if the world follows the same behavioral pattern. According to predictions, scientists invented the birth control pill and set population control through eugenics. Despite that, population continued to increase and fight with constant diseases. Migration was another component that encouraged population rise, which imposes severe threats to the environment. Urbanization destroys natural habitats and reinforces carbon dioxide emissions, which cause climate change and global warming. Species are becoming extinct and humanity is at threat that it set up for itself. Food scarcity and shortage of water as well as lack of job opportunities and inadequate education are the results of global inequality. Uneven distribution of natural resources, financial means, and individual rights give rise to poverty and define the global culture as greedy, despite the aid of international organizations and agencies. Solutions to overpopulation lie in the efforts of national institutions to implement policies that will correspond to the guidelines given by international institutions that work for the best of the global community. Within this global network, individuals act in their best interest, leaving the rest in extreme poverty and shortage. The inequality supports issues that contribute to overpopulation and leads to a humanity’s extinction.

Recommended Citation

Baus, Doris, "Overpopulation and the Impact on the Environment" (2017). CUNY Academic Works. https://academicworks.cuny.edu/gc_etds/1906

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Human Overpopulation: Causes and Effects in Developing Countries

This research paper outlines the causes and effects of human overpopulation, focusing in developing countries. The primary cause of this problems includes low mortality rates coupled with high birth rates. The exponential influx in human overpopulation has had negative effects on both the economic stability and environment of the affected countries. In addition to the causes and effects discussed, potential solutions are proposed to assist in the mitigation of the problem.

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Egyptian STEM schools

Mina Eskandar

Over-population is a great Problem for many countries. This research looks into all possible solutions for this problem. World population has jumped from about 2.5 billion in 1951 to 7.8 billion in April 2020 , 212% increase. Over-population has been an issue for many countries especially in Africa, as Africa has the highest fertility rate ,children per woman, and Africans are low on resources especially for those who live in the middle of Africa ,in other words, near the equator, Because of its hot weather and being low on water, it is optimum environment for spreading diseases and droughts which its direct relation to overpopulation was later discovered resulting in lack of resources and slowness of economy development. Human Resources management has important terminology which need to be understood before getting into our main topic: fertility rate is the average children per woman, birth rate is the average number of children born per year and death rate is the number of deaths per year, natural change is the birth rate minus the death rate . Social Scientists have many theories on what causes over-population, Some suggest that poverty is the main cause of over-population as it is seen in most poor countries like in Africa unlike rich countries in Europe. They suggest that families try to overcome their poor condition by having more children. But other scientists argue that it can be correlation and something else is causing both of them. They suggest that it is a high death rates. Also, through comparing between poor Countries and rich Countries, it can be notice that in poor countries, death rates are high as of that most families give birth to many children. There are other suggested causes like lack of education and child labor. Over-population can cause many serious problems especially for poor countries. For example, It can cause lack of water in developing countries because as the population grow, water consumption increases. For countries that do not have a fresh stable water source, This can lead to droughts and lower life expectancy. Also, population growth could cause Extinction of wild life and pollution because forests and natural environments for various animals are cut down to free more space for buildings and cities. green house effect was learned in (CH.2.11) about and learned In (ES.2.10) about the role of plants in stabilizing the carbon dioxide percentage and the role of forest in keeping biodiversity in (BI.2.12). For These reasons, Countries tried to solve this issue, because of its significant impact on the economy and the productivity. Some of these solutions were the “one-child-policy” and “two-child-policy” tried by China to control population growth using the law. The Results of them were very fast. Other places tried to control over-population by focusing on education especially for girls like in Europe in the 19 th century. To conclude, This research will focus on these prior solutions and others and discuss why they work.

International Journal of Science, Technology and Society

Casmir Onyeneke

Overpopulation is an immensely dangerous problem that does not affect only individual countries but worldwide. It has many causes such as immigration; early marriages, poor medical access, and education are the main reasons to be indicated. While it has many reasons why the earth faces overcrowded, overpopulation's effects are considered a perilous crisis more than itself. In the past, researchers have explored how to stop this rising problem even though; they have tried several ways from mass sterilization to awarding families with no child. None of these approaches worked instead, people tend to have more children and take this dangerous risk. Therefore, depletion of natural resources, rise in pollution, epidemics, and other diseases are the main consequences of overpopulation which this literature review has discussed. Even though scientists and nature activists have argued about the effects of overcrowding on the earth, humankind, and health, there is no right solution taken by us: humans as a creator of this crisis. Furthermore, this research will concentrate on the possible effects of overpopulation on the earth, health, and human kind. Plus, it suggests some possible solutions. Significantly, it illustrates how overpopulation will impact natural resources and human health.

Sandu Szilveszter

The purpose of this paper is to shed light on the overpopulation issue of India and propose recommendations on how to overcome it. First, the paper summarizes the crucial demographic conditions and where India stands by numbers. Then the article presents the development of the state approach to the issue starting from the early years of independence up to the current policies. It does so by scrutinizing its cultural, economic and social factors and implications of overpopulation and identifies socioeconomic backwardness, early marriages and family norms, lack of adequate health care infrastructure and education as the correlated and interdependent features supporting the trend of overpopulation. The authors come up with three recommendations to tackle the issue – women empowerment, education and industrialization.

Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences

Wolfgang Lutz

The 20th century has seen unprecedented growth of the human population on this planet. While at the beginning of the century the Earth had an estimated 1.6 billion inhabitants, this number grew to 6.1 billion by the end of the century, and further significant growth is a near certainty. This paper tries to summarize what factors lie behind this extraordinary expansion of the human population and what population growth we can expect for the future. It discusses the concept of demographic transition and the preconditions for a lasting secular fertility decline. Recent fertility declines in all parts of the world now make it likely that human population growth will come to an end over the course of this century, but in parts of the developing world significant population growth is still to be expected over the coming decades. The slowing of population growth through declining birth rates, together with still increasing life expectancy, will result in a strong ageing of population age s...

Joseph A Heath

Analysis of how to tackle this issue. Written in spring 2016.

Environmental and Resource Economics

john Cleland

Thandolwenkosi Mthembu

Rapid population growth has been a topic of contestation on a socio-economic, statistical and environmental stance. It has proven to be a great cause for concern in much literature with regards to resource scarcity and the earth’s capacity to withstand the impact thereof, it’s hindrance to economic and social development and it’s threat to global political stability. It is important to note that 80 percent of the world’s population is found in low income countries (Hewitt) and in as much as it has been proven that population growth is exponential in these areas, it has not been resolved that one is poor because they have many children. Quite the opposite has been argued of which recent literature on the relationship between population and development has illustrated. When looking specifically at overpopulation in relation to development, there are two standpoints. The first one sees population growth being the barrier to sustainable development efforts as a whole, and much like the Malthusian Theory it urges control over population growth. The other standpoint denounces claims that overpopulation is the cause of social and economic development problems, but says it is a symptom of it. This essay will be looking at both standpoints so as to critically evaluate whether overpopulation really is the principle cause of development problems.

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The Overpopulation Project

TOP – Research and Outreach

Too many people consuming too much

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Meet the Nigerian Teacher Who Advocates for Family Planning

Coming from a family of seven children, Chidera Benoit knows better than anyone how challenging it is to grow up in a big family in Nigeria and achieve a good living standard. Convinced that Nigerian women and men should be free to decide their family size, this young and motivated teacher and Executive Director of the Population Explosion Awareness Initiative travels across the country to raise awareness about voluntary family planning, smaller families and a sustainable population. 

Interview by Veronika Perková

Read and comment on the full blog

Over the past two centuries Earth’s human population has doubled, and doubled again, and doubled yet again, increasing from 1 billion to over 8 billion people. This huge increase is at the root of grave global environmental problems, from climate change to mass species extinction. The aim of The Overpopulation Project (TOP) is to study and highlight the environmental impacts of overpopulation, including humane policies to end population growth around the world. Initiated in 2017 with a generous two-year grant from the Global Challenges Foundation, TOP plans to continue its work through donations from supporters.

Our Motivation

People are overstressing the Earth: using too many resources, generating too much waste, and leaving polluted landscapes and empty seas in our wake. But this is the only home we have. Our descendants will depend on Earth’s ecosystem services for their health and well-being, just as we do. Ten million other species also need sufficient habitat and essential resources to survive and thrive. We have no right to extinguish them ; instead, we have a responsibility to create ecologically sustainable societies that allow all Earth’s life forms to flourish.

Limiting human numbers must be part of this effort. Yet environmentalists rarely acknowledge this—either because we think population growth is no longer a problem, or because we think the problem will solve itself. Neither is true. Excessive family size sends tens of millions of children to bed hungry each night in the developing world, where rapid population growth stresses scarce water, food and space resources beyond safe limits. Meanwhile continued population growth leads to deforestation, ailing coral reefs , and paved over farm lands and wetlands. Around the world, most national populations continue to grow and the United Nations projects a massive increase of 3 billion more people by 2100.

The Overpopulation Project studies the environmental impacts of overpopulation in an effort to remind environmentalists, scientists and policy makers of the contributions ending population growth can make in dealing successfully with global environmental problems. Believing that much of this century’s projected population increase could be avoided with the right public policies, it also explores humane policies to end population growth sooner rather than later.

The views and opinions expressed in guest blog posts are those of the authors and do not necessarily reflect the position of The Overpopulation Project.

Explore the content and topics covered by TOP, search here

Recent blog posts.

• Meet the Nigerian Teacher Who Advocates for Family Planning May 21, 2024
• Why Modern Monetary Theory is good news for population policy May 14, 2024
• New State of the World Population report conceals family planning as UNFPA’s most successful product May 7, 2024
• Carl Wahren (1933-2024), In Memoriam April 24, 2024
• The Truth about Abortion April 16, 2024

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What we are reading, listening to and watching.

• News and updates from FP2030 by FP2030
• Myths about overpopulation by Peter Uetz
• Net benefit of smaller human populations to environmental integrity and individual health and wellbeing by Saraswati et al.
• Renowned Indian yogi Sadghuru at World Economic Forum by lakarupproret
• Immigration Surges to Top of Most Important Problem List by Jeffrey M. Jones

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Gallery of infographics – Learn more about overpopulation and environment

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What is the myth of overpopulation?

The myth of overpopulation is an unfounded belief that:

the number of people on Earth will exceed the carrying capacity of the planet in the foreseeable future, leading to economic or social collapse, and that actions ought to be taken to curb population growth.

Where did the overpopulation myth come from?​

In 1798, an Anglican minister by the name of Thomas Malthus published the first edition of his An Essay on the Principle of Population where he speculated that, under perfect economic conditions, humans reproduce exponentially while their ability to increase agricultural output increases only linearly at best.

Malthus theorized that there were two kinds of “checks” that kept the population growth rate in check with the food supply.

What was the affect of Malthus' theory?

How does the myth of overpopulation affect us globally?​

Malthus’ ideas quickly became the foundation for a movement that began to preach population control and contraception as the keys to socioeconomic development and the betterment of Western society.

Governments today are pushing population control policies in order to control the number of children being born as a protective measure to their national resources. All of these policies have received global recognition of their brutality:

• China’s one-child policy , where women were severely fined, arrested, or forcibly sterilized for exceeding the birth limit.
• India’s sex-selective abortion where approximately 15.8 million girls have been eliminated since 1990 due to a cultural preference for boys. Now the government wants to impose their own two-child policy.
• Latin America’s forced sterilization programs where women where arrested for being pregnant and their babies where aborted in unsanitary conditions.
• The United Nation’s ‘education programs’ that refuse aid to developing countries unless they accept contraception, abortion, and sterilization to prevent the false idea of population over-growth.

Watch our Videos on the Myth of Overpopulation Below

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Universe 25 'Rodent Utopia' Experiment Doesn't Mean Human Society Is Dying

John calhoun's "rodent utopia" experiments have been frequently used as evidence for "societal decay.", published may 21, 2024.

The closest thing to utopia the world has ever seen might have existed in a Maryland barn for a couple of years during the late 1960s: a complex built for rodents as part of a science experiment.

The study had an interesting premise and shocking results — a failed society that pushed itself into extinction. Almost immediately, scientists and laypeople alike began suggesting it could be apocalyptic prediction of the future of humanity. In other words, it was almost tailor-made for internet virality.

Snopes readers have written many emails over the last few years asking us about the notorious rodent utopia experiment, sometimes called "Universe 25."

The Background

Before explaining the experiment, it's important to understand why it   was performed. While environmentalism as a political theory had been around in bits and pieces since the early days of the Industrial Revolution, it was not until just after World War II that people truly began to politically organize around the environment.

One of the largest fears at the time was overpopulation — sometimes called Malthusianism after an 18th-century demographer, Thomas Malthus , who proposed that population would eventually grow faster than food production, meaning that, eventually, humanity would be unable to feed everyone. Many early environmentalists proposed similar ideas.

In the 1950s, an animal behaviorist named John Calhoun started working at the National Institute of Mental Health. He had long worked with rats, the subject of his Ph.D. thesis, and was interested in studying how a rat society would develop over time when it was limited only   by space. In other words, he wanted to test the effects of overpopulation.

In order to run his experiment, Calhoun designed complexes, which he named "Universes," that would provide his rodent subjects all they needed to survive — food, water and protection from predators and disease. The only thing that would limit the population growth would be space. 

As he watched the rodent societies grow, he began noticing strange trends:

Pregnant females began having problems raising offspring. Dominant males became incredibly territorial and overactive, while subordinate males increasingly withdrew from the larger group, coming out "to eat, drink and move about only when other members of the community were asleep." Rats became so conditioned to eating with others that they would refuse to eat alone. Some males became hypersexual and attempted to mate with anyone and everyone. Fighting was frequent. Rats began cannibalizing other rats. At one point, the infant mortality rate reached an astonishing 96%.

As one of Calhoun's assistants put it, "utopia" had turned into a "hell."

The Experiments

Calhoun published the results of his early experiments in the February 1962 edition of Scientific American, with the title " Population Density and Social Pathology ," coining the term " behavioral sink " to describe the most-crowded spots, where he observed the highest rate of antisocial behavior. In the 1960s, at the height of political discourse about so-called "social decay" in American cities, the study was a natural discussion topic. In the meantime, Calhoun continued his work.

And now we arrive the 25th version of this study Calhoun ran, and the one he would become most well-known for: Universe 25. It was the only one of Calhoun's habitats fully studied from beginning to end. Universe 25 was populated with mice instead of rats, but most everything else remained the same. Mice had everything they needed to survive and were limited only by space.

Calhoun constructed a square box with a side length of 54 inches. He built nesting boxes, water bottles and food hoppers into the walls, with each side of the universe having 64 different nesting boxes located at various heights, 16 water bottles and four food hoppers. All of the "utilities" were accessible via a series of mesh tunnels running from the floor up the side of the wall.

Calhoun published the results of Universe 25 in 1973 in a paper called " Death Squared: The Explosive Growth and Demise of a Mouse Population ." He broke down the development and collapse of the society into four phases:

• Phase A, consisting of the first 104 days, was the adjustment phase, with "considerable social turmoil" between the eight original mice placed into the habitat. Phase A ended once the mice had their first offspring.
• Phase B, which Calhoun named the resource exploitation phase, lasted from Day 105 to Day 315. During this phase, the population grew rapidly, reaching more than 600 mice before growth began slowing. Social stratification also began to happen, with different groups of mice living in certain areas and self-selecting into their own independent groups.
• Phase C, called the stagnation phase, lasted from Day 316 to Day 560. Male mice who were not able to find room in the pre-existing social structure began to withdraw from society, violently attacking one another. Their female counterparts retreated into the highest boxes, also isolating themselves. Socially dominant males began to lose control over their territory, leaving mothers to aggressively defend their young, sometimes even abandoning them. "For all practical purposes there had been a death of societal organization by the end of Phase C," Calhoun wrote.
• Phase D was the death phase. The death rate outpaced the birth rate, and the society began to shrink. Mothers raised newborn mice for a very short time, and Calhoun proposed that the young generation's strange behaviors were a direct result of a very abnormal social upbringing that did not allow some of the more "complex behaviors," including mating rituals, to develop. Females rarely gave birth, and a large group of males, which Calhoun named the "beautiful ones," did nothing other than eat, drink, sleep and groom themselves. During Phase D, a few mice were placed in newly established universes to see whether they would relearn those social behaviors. They did not.

Calhoun's 1973 paper was not subtle. "I shall largely speak of mice, but my thoughts are on man, on healing, on life and its evolution," he wrote. He made frequent references to the Book of Revelation in the Bible and almost all of his wording aimed to personify his rodent subjects. The mice in Universe 25 lived in "walk-up apartments," and Calhoun described subgroups like "somnambulists" or the "bar flies," terms that could easily be mapped to urban life.

The conclusions felt grim, and the fears of overpopulation made their way into pop culture , like the movie "Soylent Green." There's even a book for children very loosely based around Calhoun's mouse cities (although without the doom and gloom of societal breakdown): "Mrs. Frisby and the Rats of NIMH."

The Conclusions

In modern times, Calhoun's Universe 25 experiment is often used as a way to talk about some kind of " degradation of Western society ." These analyses look at Calhoun's experiments and say, "He predicted this would happen to humans, and look at all the cultural degeneracy we see today!" For instance, here's an excerpt from a comment about the experiment we've seen repeatedly on Facebook :

According to Calhoun, the death phase consisted of two stages: the "first death" and "second death." The former was characterized by the loss of purpose in life beyond mere existence — no desire to mate, raise young or establish a role within society. As time went on, juvenile mortality reached 100% and reproduction reached zero. Among the endangered mice, homosexuality was observed and, at the same time, cannibalism increased, despite the fact that there was plenty of food. Two years after the start of the experiment, the last baby of the colony was born. By 1973, he had killed the last mouse in the Universe 25. John Calhoun repeated the same experiment 25 more times, and each time the result was the same. Calhoun's scientific work has been used as a model for interpreting social collapse, and his research serves as a focal point for the study of urban sociology. We are currently witnessing direct parallels in today's society ... weak, feminized men with little to no skills and no protection instincts, and overly agitated and aggressive females with no maternal instincts.

Scientists have repeatedly pushed back against these ideas since Calhoun's research came out. Researchers who attempted to replicate Calhoun's studies in humans found mixed results, and other scientists chastised him for extrapolating rodent behavior to humans. While the popular conception of Universe 25 focused on the apocalyptic death of society because of overpopulation, other psychologists suggested otherwise. 

In an 2008 interview with the NIH Record , Dr. Edmund Ramsden, a science historian, explained the results of a similar 1975 experiment by a psychologist Jonathan Freedman:

Freedman's work, Ramsden noted, suggested that density was no longer a primary explanatory variable for society's ruin. A distinction was drawn between animals and humans. "Rats may suffer from crowding; human beings can cope… Calhoun's research was seen not only as questionable, but also as dangerous." Freedman suggested a different conclusion, though. Moral decay resulted "not from density, but from excessive social interaction," Ramsden explained. "Not all of Calhoun's rats had gone berserk. Those who managed to control space led relatively normal lives." Striking the right balance between privacy and community, Freedman argued, would reduce social pathology. It was the unwanted unavoidable social interaction that drove even fairly social creatures mad, he believed.

But what the modern critics often carelessly and conveniently leave out is how Calhoun's research evolved after Universe 25: Up until his death in 1995, Calhoun looked for solutions to the problem he had discovered, altering his designs and controls to try to   avoid the societal collapse of Universe 25. He described rodents coming up with creative solutions to daily tasks. And it was in this way that his experiments have actually proven more useful. Architects and urban designers have taken Calhoun's experiments into consideration when designing buildings and cities. Prison researchers and reformers have also found Calhoun's studies surprisingly helpful.

So yes, while Universe 25 and Calhoun's "rodent utopias" were real experiments, they're not the apocalyptic predictions that some people make them out to be. 

Arnason, Gardar. "The Emergence and Development of Animal Research Ethics: A Review with a Focus on Nonhuman Primates."  Science and Engineering Ethics , vol. 26, no. 4, 2020, pp. 2277–93.  PubMed Central , https://doi.org/10.1007/s11948-020-00219-z.

Britannica Money . 18 Mar. 2024, https://www.britannica.com/money/Malthusianism.

Calhoun, John B. "Death Squared: The Explosive Growth and Demise of a Mouse Population."  Proceedings of the Royal Society of Medicine , vol. 66, no. 1P2, Jan. 1973, pp. 80–88.  DOI.org (Crossref) , https://doi.org/10.1177/00359157730661P202.

Calhoun, John B. "Population Density and Social Pathology."  California Medicine , vol. 113, no. 5, Nov. 1970, p. 54.  PubMed Central , https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1501789/.

---. "Space and the Strategy of Life."  Behavior and Environment: The Use of Space by Animals and Men , edited by Aristide Henri Esser, Springer US, 1971, pp. 329–87.  Springer Link , https://doi.org/10.1007/978-1-4684-1893-4_25.

Edmund Ramsden and Jon Adams. "Escaping the Laboratory: The Rodent Experiments of John B. Calhoun & Their Cultural Influence."  Journal of Social History , vol. 42, no. 3, 2009, pp. 761–92.  DOI.org (Crossref) , https://doi.org/10.1353/jsh.0.0156.

Environmentalism | Ideology, History, & Types | Britannica . https://www.britannica.com/topic/environmentalism. Accessed 17 May 2024.

Fredrik Knudsen.  The Mouse Utopia Experiments | Down the Rabbit Hole . 2017.  YouTube , https://www.youtube.com/watch?v=NgGLFozNM2o.

Garnett, Carla. "Medical Historian Examines NIMH Experiments In Crowding."  NIH Record , Vol. LX, No. 15, 25 July 2008, https://nihrecord.nih.gov/sites/recordNIH/files/pdf/2008/NIH-Record-2008-07-25.pdf.

Magazine, Smithsonian, and Maris Fessenden. "How 1960s Mouse Utopias Led to Grim Predictions for Future of Humanity."  Smithsonian Magazine , https://www.smithsonianmag.com/smart-news/how-mouse-utopias-1960s-led-grim-predictions-humans-180954423/. Accessed 17 May 2024.

Magazine, Smithsonian, and Charles C. Mann. "The Book That Incited a Worldwide Fear of Overpopulation."  Smithsonian Magazine , https://www.smithsonianmag.com/innovation/book-incited-worldwide-fear-overpopulation-180967499/. Accessed 17 May 2024.

Paulus, Paul.  Prisons Crowding: A Psychological Perspective . Springer Science & Business Media, 2012.

Ramsden, Edmund. "The Urban Animal: Population Density and Social Pathology in Rodents and Humans."  Bulletin of the World Health Organization , vol. 87, no. 2, Feb. 2009, p. 82.  PubMed Central , https://doi.org/10.2471/BLT.09.062836.

The Calhoun Rodent Experiments: The Real-Life Rats of NIMH . https://cosmosmagazine.com/science/mathematics/calhoun-rodent-experiments/. Accessed 17 May 2024.

"Universe 25, 1968–1973."  The Scientist Magazine® , https://www.the-scientist.com/universe-25-1968-1973-69941. Accessed 17 May 2024.

Woodstream, Woodstream.  What Humans Can Learn from Calhoun's Rodent Utopia . https://www.victorpest.com/articles/what-humans-can-learn-from-calhouns-rodent-utopia. Accessed 17 May 2024.

By Jack Izzo

Jack Izzo is a Chicago-based journalist and two-time "Jeopardy!" alumnus.

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'Furiosa' Joins the Small but Growing Number of Climate Change Films

W hen the highly anticipated Furiosa: A Mad Max Saga hits theaters this week, moviegoers will return to director George Miller's dystopian desert vision of a world undone by ecological catastrophe and climate change.

Miller first had Mad Max and other ragged desperados racing for the last drops of water and gasoline back in 1979. Since then, as New York Times chief film critic Manohla Dargis wrote last week in her (favorable) Furiosa review, "the distance between Miller's scorched earth and ours has narrowed."

Indeed, in 1979 the atmospheric concentration of carbon dioxide, the most important greenhouse gas causing our world to warm, hovered just under 340 parts per million (ppm). Today, CO2 levels have rocketed to nearly 427 ppm, and average global temperatures have been rising in tandem.

Last year was the hottest on record and brought extreme storms, heat waves and wildfires that scientists had long warned would come with a changing climate . According to one recent study, the summer of 2023 was the Northern Hemisphere's hottest in 2,000 years.

But while we can see the growing evidence of a crisis around us with alarming frequency, we do not often see climate change depicted when we go to the movies. According to a recent survey of top films, Furiosa will be among the just under 10 percent of major movies released in the past decade that acknowledge climate change.

That's a problem, climate activist Anna Jane Joyner told Newsweek . Good Energy, the group she founded and leads, works as a "story consultancy" to give climate change a larger presence in Hollywood films.

"They are the most powerful storytelling engine in our world," Joyner said. "So, it's really important that climate shows up."

Good Energy partnered with the Buck Lab for Climate and Environment at Colby College to publish a review of the 250 most popular fictional films released between 2013 and 2022. The Buck Lab researchers found that only 9.6 percent of the movies meet the group's test for climate reality in film narratives.

The findings come at a pivotal time as the industry struggles to find its footing amid streaming technology and competition from other entertainment sources, possibly reducing the appetite for scripts that tackle tough social topics.

A leading studio that had championed climate change and other causes, Participant Media, recently announced its closure, prompting an open letter from Hollywood A-listers including George Clooney, Don Cheadle and Ava DuVernay urging studio executives not to give up on issue-oriented movies.

Joyner said the stakes go far beyond the world of films into the realm of climate action, which she said needs the public attention movies can provide.

"There's not been a social movement in history that won without engaging storytellers and artists," she said.

The Climate Reality Test

Joyner said climate change can show up in films in a wide variety of ways, and the Buck Lab and Good Energy developed a methodology to assess those called the climate reality test.

"It just tests the baseline," she said. "Does climate change exist in the world of this story, and does a character know it?"

Among the rather short list of movies that meet that test, many fall in the superhero and big-budget action genres. Climate change is often part of a dystopian future or a villain's plot the heroes must avert. Aquaman , Fantastic Four , Justice League and The Amazing Spiderman 2 all passed the test and made the Good Energy list.

In others, a film's plot might not hinge on climate change, but the issue is present in dialogue.

"This is also very psychologically important for normalizing conversations around climate change and validating an audience's own emotional experience," Joyner said. The 2019 drama Marriage Story falls in this category (and is among Joyner's personal favorites).

Then there is a category of films in which the writers and producers create what Joyner calls a "climate world."

"It's when climate is a context of the story that comes up over time," she said. "It's woven in throughout the story, it affects the characters' lives and it actually affects the storylines."

Joyner places the 2022 film Glass Onion in this category. Ed Norton's character promotes a clean-energy technology that drives the plot and (spoiler alert) turns out to be disastrously dangerous.

Despite the low percentage of films that passed the test, Joyner said she finds reasons for optimism in the survey results. An earlier study her group published ranking thousands of movie and television scripts found just under 3 percent acknowledged climate change.

"At least we're moving in the right direction," she said.

There was also a positive trend over the period the group measured in the recent survey. Twice as many films released in the second half of the decade passed the climate test compared to those from the first half of the decade.

And Joyner pointed out something from the box office results. According to the survey, films that met at least part of the climate test performed 10 percent better than those that did not.

She's not claiming that climate content is a guaranteed moneymaker, she said. Rather, she viewed the findings as evidence that movie producers shouldn't be afraid of alienating audiences when they address the reality of climate change.

"It's definitely not hurting the profitability of these films," she said.

A Deep Eco-Cinematic History

Activists like Joyner are following in a long history of environmental themes in film stretching back to the very origins of cinema, according to authors Joseph Heumann and Robin Murray.

Both are emeritus professors at Eastern Illinois University, he in communication studies and she in English, and together they've written eight books on how movies have depicted ecological issues.

The earliest example they cite comes from the Lumière brothers, French pioneers of early filmmaking. In a short film from 1896, the Lumières used footage shot in Baku, Azerbaijan, site of one of the first large oil discoveries.

"The way that people looked at what we would call an eco-disaster today was that it was this amazing production of oil," Heumann told Newsweek . He said the film shows a figure walking in front of giant wells spewing oil into the air.

"You can see how horrible and toxic the environment is, but that the figure doesn't seem to care," he said.

Heumann and Murray explore how various environmental themes show up in horror, action, westerns and even comedy over the years. They said they've found that environmental themes in films tend to cycle with the overall public profile of ecological issues.

The 1970s saw the rise of the environmental movement, the energy crisis and the first Earth Day, and there was a corresponding surge in movies with those themes.

"We have films from the '70s that were responding to this new vision for environmental change," Murray said.

One film from that period, the 1973 science-fiction movie Soylent Green , is one of the first major movies to mention "the greenhouse effect." Charlton Heston struggles through the heat in what must be one of the sweatiest movies ever made—each character is covered with a shiny layer—amid a landscape beset by overpopulation and, of course, hunger.

While climate might be missing from many big-budget fiction films today, Murray said, she sees a boom in small-budget, independent and documentary films tackling environmental themes.

"We're seeing, I think, more of those films because there's more awareness of climate change," she said.

The question, Heumann said, is whether those films motivate viewers to act.

"You can give the audience members knowledge, and some of that knowledge they'll take away, but it doesn't necessarily translate to activism yet," he said.

In a historic plot twist worthy of a Hollywood script, Baku, Azerbaijan—scene of the Lumière brothers' early film about oil—will host the annual United Nations climate talks, COP29, this November.

A Personal Climate Connection

One film on the Good Energy survey list that most explicitly deals with climate change hardly mentions it—at least not directly. Don't Look Up , from 2021, starred Leonardo DiCaprio and Jennifer Lawrence as a pair of scientists trying to warn an oblivious, pop culture-saturated society about an impending collision with a comet.

The comet becomes a metaphorical stand-in for climate change, allowing director Adam McKay a chance for some darkly comic commentary on the political and media obstacles to addressing the crisis.

Joyner said the film connected with her as someone who has been involved in climate communications for two decades.

"It was so cathartic to see that on screen because that was like the first ten years of my career," Joyner said, comparing the public response to climate warnings to the blasé response to the comet in the film. "It's like, 'There's a comet coming at us!' And it doesn't seem like anyone in my life or in our country or world cares. And am I going crazy?"

Joyner traces her climate activism to her early surroundings and upbringing. She grew up on the Gulf Coast, an environment that's highly vulnerable to climate impacts such as sea level rise and extreme weather, and she said that her father, a megachurch preacher and author on conservative political themes, is a climate change skeptic. (He's recently moderated his view, she said.)

Her relationship with her father and her efforts to sway his opinion were depicted in the Emmy Award-winning documentary Years of Living Dangerously .

"I've had my share of climate anxiety and grief and anger and other dark emotions," Joyner said of her work on the issue. She said she often finds herself turning to stories to help process those feelings.

"In the age of climate change, that's where we go to find meaning, and we always have," she said, explaining the direction of her activism with Good Energy. "That's why I thought, Focus on Hollywood."

Update 5/20/2024, 11:00 a.m. ET: This story was updated to clarify the role the Buck Lab played in the film research.

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