Are There Too Many Humans on Earth?

The UN estimated that the eight billionth person on Earth was born on Novembet 15, 2022. With the planet’s massive population growing larger and larger, many have begun to fear the effects of overpopulation: starvation, catastrophic environmental damage, and running out of freshwater. These fears spark an important debate: Are there too many humans on Earth?

In science, carrying capacity refers to the maximum number of individuals of a species that the environment can sustainably support; overpopulation occurs when carrying capacity has been exceeded. In general, there are three main viewpoints toward human overpopulation. The first is the idea that Earth has already reached carrying capacity, meaning our population is already greater than what the environment can handle. The second is that the Earth will never reach carrying capacity, or at least not for a very long time. The third is that Earth will reach its carrying capacity soon, most likely in the next few decades.

The grim effects of overpopulation were first widely introduced to the public in the 18th century by a statistician named Thomas Malthus. Malthus claimed that the human population would, without a doubt, eventually be greater than what Earth could sustain. He believed that once the Earth was overpopulated, there would be desolation, famine, and war. Though the human population has grown exponentially higher since Malthus’s time, agricultural productivity and the overall standard of living have vastly improved in most areas, putting off the devastating effects described by Malthus.

The argument that humans have already surpassed Earth’s carrying capacity primarily comes from our massive impact on the environment. Our ecological footprint, which includes land usage, food, and energy, is used to measure the amount of natural resources that humans consume and the wastes we generate. A huge percentage of our ecological footprint is attributed to our carbon footprint—the total amount of greenhouse gasses we produce—which results primarily from the burning of fossil fuels. This contributes heavily to climate change, air pollution, and acid rain, as fossil fuels make up 75 percent of greenhouse gas emissions worldwide. The effects of our carbon footprint gradually deteriorate our environment, which leads to poorer living conditions and possible extinction for plants, animals, and humans.

Additionally, a region’s biocapacity measures the amount of natural resources available in the region and the ecosystem’s ability to absorb the waste generated by humans. When a region’s ecological footprint is greater than its biocapacity, the region can’t regenerate resources fast enough to keep up with human demand for natural resources. Our ecological footprint is far greater than the world’s biocapacity. At our current rate, it would take around 1.75 Earths to sustain the demands of our population, primarily our energy demands. This massive overexploitation of Earth’s natural resources has led many to believe that the Earth won't be able to sustain our demand for much longer. For instance, the world’s supply of oil is predicted to last only up to around 2050.

On the other hand, some people believe that humans will never reach Earth’s carrying capacity, or at least not for a very long time. This is mainly due to the fact that the carrying capacity of the Earth is not fixed and has the potential to increase or decrease. This potential to increase can be unlocked through new technologies; one example is switching to clean energy sources such as solar power or nuclear energy to combat our carbon footprint. The past 50 years of using nuclear energy has reduced two years worth of worldwide energy-related carbon emissions. If we drastically reduce our ecological footprint through clean energy sources, it could fall lower than the Earth’s biocapacity, allowing the Earth to regenerate and replenish its natural resources.

With contemporary technologies such as fertilizers and pesticides, we are able to produce a lot more food than ever before. In fact, we are currently producing around 150 percent more food worldwide than we were in 1960, while using only 13 percent more land. We could also feed a lot more people through a dietary shift toward vegetarianism, since currently 36 percent of the grain produced worldwide is used to feed livestock, which is highly inefficient; it takes about 2.5 pounds of grain to make one pound of beef. By combining agricultural technology with a dietary change, we would be able to produce a surplus of food. By reducing our ecological footprint and increasing our food supply, we could theoretically drastically increase the amount of time until we reach Earth’s carrying capacity.

However, many believe that we’ll reach our carrying capacity soon. Demographers at the UN and many other scientists believe that Earth’s human carrying capacity is around 10.4 billion. The UN predicts that we’ll reach 10.4 billion humans by 2100 and our population will then level off. This 10.4 billion estimate is based primarily around the availability of freshwater and food. It is predicted that there will be freshwater shortages starting in 2050. Fortunately, this is expected to be counteracted by new technology such as desalination, a process used to extract drinking water from seawater. Though we currently produce enough food to feed a population of 10 billion people, around a third of this food is wasted. This comes primarily in the form of leftovers, unbought food in grocery stores, and unharvested produce on farms that is either thrown out or rots. In addition, it is highly unlikely that we would be able to convince a large majority of the population to give up meat and transition to a vegetarian diet in order to feed more people.

Nevertheless, it is predicted that a population of 10.4 billion would be the peak human population, even if we didn’t reach carrying capacity. This is primarily due to a decrease in birth rate in many countries, especially core countries, as well as a decreasing infant mortality due to more accessible healthcare. Many countries, especially those in Europe and East Asia, currently have an average of less than 2.1 children per woman, which is the fertility rate required to fully replace the population. This has led to the implementation of policies promoting repopulation, such as in China, where families who raise children are given subsidies. Though the population continues to grow due to high birth rates in developing countries, this growth is slowing down.

The debate around overpopulation is complex and multifaceted. Our ecological footprint, tied directly to our very large population, is becoming a growing issue. To combat this, new technology and lifestyle changes will be needed to sustain our growing numbers. Achieving a balance between population growth, resource management, and technological advancements will play a crucial role in shaping our future.