Nature's Limits

Human Overpopulation: A Huge and Growing Crisis for Earth’s Ecosystems

In writing this, we want to be absolutely clear about our views. We love children and are not in a position to dictate who can and cannot have children, nor do we desire to do so. That aside, the Earth can only sustain so many people, and we hope everyone will understand the effects of overpopulation when making their own decisions about having children. If we make wise choices, all of us, especially those who follow us, will reap the benefits of limiting population growth to sustainable levels or pay the price if we don’t.

The Bank Called Earth

The explosive growth of the human population is threatening the ecosystems that sustain all life on Earth. As stated by Worldometers, “A tremendous change occurred with the industrial revolution: whereas it had taken all of human history until around 1800 for world population to reach one billion, the second billion was achieved in only 130 years (1930), the third billion in 30 years (1960), the fourth billion in 15 years (1974), and the fifth billion in only 13 years (1987).”

According to the United Nations, the world’s population will grow from 8.2 billion in 2024 to around 10.2 billion by the end of the century. We are already seeing an intensifying environmental crisis, and the addition of 2 billion more people will create much larger destruction of the environment directly linked to human overpopulation. We will have outpaced the Earth’s capacity to regenerate resources and absorb our waste.

 The rapid expansion of humanity is the root cause of many of our most pressing current environmental challenges. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) reports that human activities have significantly altered 75% of the Earth’s land surface and 66% of ocean areas, primarily due to population growth and increased per capita consumption. From climate change to mass extinction, the fingerprints of overpopulation are evident in virtually every ecological crisis we face today. 

Our activities are not sustainable as the sheer scale of human resource consumption is overwhelming the planet’s natural systems. Each additional birth brings increased food, water, energy, and living space demands. While one child is not placing undue demands on resources, when joined with billions of others, the problems become supercharged.

The Global Footprint Network estimates that we currently use resources at a rate “1.7 times faster than our planet’s ecosystem can regenerate”, a situation that becomes more dire as our populations grow. 

One of the most visible impacts of overpopulation is widespread habitat destruction. As we clear land for agriculture and urban development to accommodate growing populations, forests, wetlands, and grasslands are destroyed alarmingly. The Amazon rainforests, often called the “lungs of the Earth,” lose thousands of square kilometers annually to make way for farms and ranches. Per gov.br, “Between August 2023 and June 2024, the area affected by deforestation alerts in the Amazon biome totaled 3,644 km²,” much of that for use by cattle farming.

Deforestation at such rates threatens countless species with extinction and disrupts crucial ecosystem services like carbon sequestration and water cycle regulation. The World Wildlife Foundation (WWF) states, “The world has seen an average 68% drop in mammal, bird, fish, reptile, and amphibian populations since 1970.” Much of that is tied to increased habitat destruction driven by the need for exploding population rises. One million species face extinction, many within decades, but certainly by the year 2100.

Environmental degradation isn’t just a problem for wildlife – it threatens human well-being too. We lose ecosystem services like water purification, pollination, food, and natural pest control. The loss of viable ecosystems will severely affect food security and public health.

Destroying vast swathes of forests to plant food crops to feed our swelling numbers is degrading soil health on a global scale. Overuse of chemical fertilizers and pesticides, while boosting short-term crop yields and animal husbandry, is poisoning ecosystems and contributing to the collapse of pollinator populations essential for both wild plants and many crops, as well as endangering millions of other uncatalogued species that provide critical services to us.

The Food and Agriculture Organization (FAO) reports that 33% of the world’s soil is moderately to highly degraded due to erosion, salinization, compaction, acidification, and chemical pollution.

Water scarcity is also critically affected, reaching critical levels in many parts of the world. Major rivers like the Colorado in the United States and the Yellow River in China frequently run dry before reaching the sea; their waters are diverted to meet the insatiable demands of expanding populations, cities, and agriculture. Groundwater aquifers are being depleted at unsustainable rates, threatening future water security for billions. Many people already live in countries or regions with absolute water scarcity, largely due to population growth and climate change. These scarcities drive famines and forced immigration, both of which are on the increase.

Overpopulation also creates massive problems for our Oceans, which comprise more than 70% of our planet’s surface. Overfishing, driven by demand from growing populations, is depleting fish stocks faster than they can replenish. The UN Food and Agriculture Organization (FAO) reported that in 2021, 37.7% of global fish stocks were being harvested at biologically unsustainable levels.

Ocean acidification, caused by the absorption of excess atmospheric carbon dioxide released by ever-increasing human use of carbon-based fuels, threatens marine food webs and is, along with record temperatures, leading to widespread coral reef death. Modeling shows that most ocean locations will not sustain coral by 2045, and almost none will exist by 2100. 

The rapid growth of urban areas to house swelling populations creates its own set of environmental challenges. Cities often expand at the expense of natural habitats, creating heat islands that stress urban wildlife and increase energy demands for cooling. This vicious cycle further contributes to climate change. By 2050, it’s estimated that 68% of the world’s population will live in urban areas, putting immense pressure on surrounding ecosystems and resources.

Perhaps most alarming, human overpopulation is a primary driver of climate change, intensifying all of the above issues. The energy demands of billions of people, mostly met through fossil fuel consumption, are altering the Earth’s climate at an unprecedented rate.

Soaring temperatures, rising sea levels, and increasingly frequent extreme weather events even now disrupt human societies and natural ecosystems worldwide. The world is already roasting, and more people means more impact on temperatures. The Intergovernmental Panel on Climate Change (IPCC) warns that without significant reductions in greenhouse gas emissions, global temperatures could rise by 3.3 degrees C to 5.7 degrees C (5.9 degrees F to 10.3 degrees F) by the end of the century. The consequences for humans and most species would be catastrophic. Recent research indicates that climate changes predicted for 2100 may start to occur as early as 2050.

Solutions Exist If We Use Them Soon

Although the above paints a scary picture, the news is not all bad. There are incredible challenges resulting from the demands on resources caused by human overpopulation. While they are daunting and will take extraordinary efforts to solve, they are manageable if addressed with multi-faceted solutions implemented by individuals and by those we elect who have the political courage to implement needed programs.

• Implement Social Safety Nets

In many societies, there are no programs to assist the elderly when they can no longer meet their own needs. With them missing, the burden of providing for elderly relatives falls entirely upon the next generations. Having as many children is seen as necessary to ensure that parents’ and grandparents’ needs are met. The result is that population increases occur.

The resulting overpopulations drive shortages as the planet’s ability to sustain so many is reached. When programs that support the elderly are in place, the need for having huge families is largely eliminated. Or, at a minimum, is not the driving factor it currently is.

• Education and empowerment

Around the world, women with secondary education have, on average, two fewer children than those without education. When women and girls are involved and educated, birth rates are lower, and population growth is more sustainable.

• Improved access to family planning resources

Education is undoubtedly critically needed, but once provided, access to birth control methods is required. Modern contraception could reduce unintended pregnancies by 75% in developing countries.

• Sustainable urban planning

Eco-efficient cities that house growing populations minimize environmental impacts. Green infrastructure, energy-efficient infrastructure, and compact city design significantly reduce per capita resource consumption and emissions.

• Transition to renewable energy

As more renewable and clean energy comes online, the needs of large populations can be met without exacerbating climate change and environmental destruction. The International Renewable Energy Agency projects that renewable energy could supply 86% of global power demand by 2050.

• Adopt sustainable agriculture

Permaculture and agroforestry are proven to produce food while preserving ecosystem health. These methods increase yields while reducing water use and chemical inputs.

• Implement water conservation

Globally, water scarcity is on the rise. Techniques like drip irrigation and wastewater recycling can dramatically improve water use efficiency. 

Global cooperation

Environmental protection and resource management are essential, and nowhere are they more difficult to implement than when the challenges are transboundary. International agreements like the Paris Climate Accord and the Convention on Biological Diversity provide frameworks for collective action, which is a start. However, implementing them and others that are needed will require politicians who honestly feel the need to protect the Earth. It is up to us to elect them.

Human population growth doesn’t have to be one of ever-rising numbers of people and inevitable ecological collapse. By recognizing overpopulation as a critical factor driving environmental degradation, including climate change, we can take steps to stabilize our numbers and reduce our impact on the planet.

Several countries have successfully stabilized their populations through a combination of education, economic development, and access to family planning services, highlighting a sustainable path forward. For instance, nations like Thailand, Iran, and Bangladesh have made significant strides in reducing birth rates and stabilizing populations by investing in women’s education, greater healthcare access, and comprehensive family planning services. These initiatives have greatly improved individual well-being and contributed to more sustainable environmental practices by reducing pressure on natural resources.

Time is Short

If the good news is that we can make changes that will save us from the worst effects of overpopulation and ecological armageddon, the bad news is that the time we have to make changes is short. Rapid population growth makes our environmental challenges more difficult to solve every year. Actions to mitigate overpopulation and its impacts are urgently needed to shape the world.

By confronting the reality of human overpopulation and its consequences, we can solve the monumental challenge that presents us with a golden opportunity to redefine our relationship with the planet and create a more balanced, sustainable world for all life on Earth.