"The power of population is so superior to the power of the Earth to produce subsistence for man, that premature death must in some shape or other visit the human race."
The late-18th century philosopher Thomas Malthus wrote these ominous words in an essay on what he saw as the dire future of humanity. Humans' unquenchable urge to reproduce, Malthus argued, would ultimately lead us to overpopulate the planet, eat up all its resources and die in a mass famine.
But what is the maximum "power of the Earth to produce subsistence," and when will our numbers push the planet to its limit? More importantly, was Malthus' vision of the future correct?
Earth's capacity
Many scientists think Earth has a maximum carrying capacity of 9 billion to 10 billion people. [ How Do You Count 7 Billion People?]
One such scientist, the eminent Harvard University sociobiologist Edward O. Wilson, bases his estimate on calculations of the Earth's available resources. As Wilson pointed out in his book "The Future of Life" (Knopf, 2002), "The constraints of the biosphere are fixed."
Aside from the limited availability of freshwater, there are indeed constraints on the amount of food that Earth can produce, just as Malthus argued more than 200 years ago. Even in the case of maximum efficiency, in which all the grains grown are dedicated to feeding humans (instead of livestock, which is an inefficient way to convert plant energy into food energy), there's still a limit to how far the available quantities can stretch. "If everyone agreed to become vegetarian, leaving little or nothing for livestock, the present 1.4 billion hectares of arable land (3.5 billion acres) would support about 10 billion people," Wilson wrote.
The 3.5 billion acres would produce approximately 2 billion tons of grains annually, he explained. That's enough to feed 10 billion vegetarians, but would only feed 2.5 billion U.S. omnivores, because so much vegetation is dedicated to livestock and poultry in the United States.
So 10 billion people is the uppermost population limit where food is concerned. Because it's extremely unlikely that everyone will agree to stop eating meat, Wilson thinks the maximum carrying capacity of the Earth based on food resources will most likely fall short of 10 billion. [ When Will Earth Run Out of Food? ]
According to population biologist Joel Cohen of Columbia University, other environmental factors that limit the Earth's carrying capacity are the nitrogen cycle, available quantities of phosphorus, and atmospheric carbon concentrations, but there is a great amount of uncertainty in the impact of all of these factors. "In truth, no one knows when or at what level peak population will be reached," Cohen told Life's Little Mysteries.
Slowing growth
Fortunately, we may be spared from entering the end-times phase of overpopulation and starvation envisioned by Malthus. According to the United Nations Population Division, the human population will hit 7 billion on or around Oct. 31, and, if its projections are correct, we're en route to a population of 9 billion by 2050, and 10 billion by 2100. However, somewhere on the road between those milestones, scientists think we'll make a U-turn.
UN estimates of global population trends show that families are getting smaller. "Empirical data from 230 countries since 1950 shows that the great majority have fertility declines," said Gerhard Heilig, chief of population estimates and projections section at the UN.
Globally, the fertility rate is falling to the "replacement level" — 2.1 children per woman, the rate at which children replace their parents (and make up for those who die young). If the global fertility rate does indeed reach replacement level by the end of the century, then the human population will stabilize between 9 billion and 10 billion. As far as Earth's capacity is concerned, we'll have gone about as far as we can go, but no farther.
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FAQs
He estimated that the world could support 13.4 billion people. Estimates in the last half of the 20th century ranged from less than 1 billion to more than 1,000 billion.
What is the maximum population the Earth can sustain? ›
A meta-analysis of 70 studies estimates the sustainable limit to the world population to 7.7 billion people. World population as of 2020: 7.8 billion...
How many people will the Earth need to support by 2050? ›
The world population is projected to reach 8.5 billion in 2030, and to increase further to 9.7 billion in 2050 and 10.4 billion by 2100.
Can Earth support 50 billion people? ›
According to Harvard University sociobiologist Edward O. Wilson, Earth does not have the capacity to hold the amount of people Andreessen projects and only has only enough resources to hold a maximum of 10 billion people.
How many people can a planet support? ›
Earth's capacity
Many scientists think Earth has a maximum carrying capacity of 9 billion to 10 billion people. [ How Do You Count 7 Billion People?] One such scientist, the eminent Harvard University sociobiologist Edward O. Wilson, bases his estimate on calculations of the Earth's available resources.
Can Earth support 11 billion? ›
In other words, there is a carrying capacity for human life on our planet. In the International Journal of Forecasting study's median scenario, the global population is 11.1 billion in 2100, 10.4 billion in 2200 and 7.5 billion in 2300. World population projected to reach 9.8 billion in 2050, and 11.2 billion in 2100.
What is Earth's carrying capacity? ›
So if everyone on Earth lived like a middle class American, then the planet might have a carrying capacity of around 2 billion. However, if people only consumed what they actually needed, then the Earth could potentially support a much higher figure.
How much longer will Earth survive? ›
Earth will interact tidally with the Sun's outer atmosphere, which would decrease Earth's orbital radius. Drag from the chromosphere of the Sun would reduce Earth's orbit. These effects will counterbalance the impact of mass loss by the Sun, and the Sun will likely engulf Earth in about 7.59 billion years from now.
What will the world be like in 3000? ›
In the year 3000, humans will exist in a world transformed by advanced technologies, AI, and robotics. They will possess enhanced physical and mental capabilities, coexisting and collaborating with intelligent machines.
What will the world population be in 3000? ›
United Nations Population Division Projection: The United Nations (UN) projects that the world population will peak around 2100 at approximately 11 billion and then start to decline [1]. If current trends continue, it is suggested that there may be no people left by the year 3000 [1].
In theory, the 100 people would need to be genetically very diverse and careful who mated with who for several generations. Otherwise, there would be excessive inbreeding, with undesirable long-term genetic consequences.
Can Earth handle 1 trillion people? ›
Technically yes, we have enough space- 197 million square miles on earth which equates to 5,492,044,800,000,000 square feet which is more than enough to have a trillion people on earth. But that assuming we manage to build on water. I mean it would still fit without oceans, just more cramped.
What if Earth was 50% bigger? ›
If our planet was 50% larger in diameter [while maintaining the same density], we would not be able to venture into space, at least using rockets for transport.
Do humans have a carrying capacity? ›
There are limits to the life-sustaining resources earth can provide us. In other words, there is a carrying capacity for human life on our planet. Carrying capacity is the maximum number of a species an environment can support indefinitely. Every species has a carrying capacity, even humans.
What will happen in 1 quadrillion years? ›
After 1 quadrillion years, probably no planet in the Solar System will be left in the system. At this time, the sun is expected to cool down to -268 degrees.
What was the lowest human population on Earth? ›
Estimates of the size of these populations are a topic of paleoanthropology. A late human population bottleneck is postulated by some scholars at approximately 70,000 years ago, during the Toba catastrophe, when hom*o sapiens population may have dropped to as low as between 1,000 and 10,000 individuals.
How many people will be left in 2050? ›
World population is expected to increase from 7 billion today to over 9 billion in 2050. A growing population is likely to increase pressures on the natural resources that supply energy and food. World GDP is projected to almost quadruple by 2050, despite the recent recession.
Will the world be livable in 2050? ›
Today, just one percent of the planet falls within so-called “barely liveable” hot zones: by 2050, the ratio could rise to almost twenty percent. In 2100, temperatures could rise so high that spending a few hours outside some major capital cities of South Asia and East Asia could be lethal.
What will happen to Earth in 2050 predictions? ›
In 2050, the world will be vastly different from what we know today, as a result of the integration of whole range of technologies, including: quantum computing, metaverse, augmented reality, nanotechnology, human brain-computer interfaces, driverless technology, artificial intelligence, workplace automation, robotics ...
How many people could there be on Earth by 2050 Anthropocene? ›
Estimates for world population show between 8 billion and 10.5 billion people living on the Earth by 2050. For much of our existence, human impact on the environment was comparable to other mammals roaming the Earth.
