No species has altered the Earth’s natural landscape the way humans have. Our impact is so extensive that we are crossing into a new geologic epoch – the Anthropocene – propelled by human behavior. Global climate change, mass extinction, and overexploitation of our global commons are all examples of the ways in which humans have altered the natural landscape. Our growing population, coupled with rising affluence and per capita impact, is driving our planet closer to its tipping point. With population expected to reach 9.5 billion by 2050, many wonder if our natural resources can keep up with our growing demands.
The World Population Map can be viewed with the data overlay, “Human Land Use,” created by ecologist Erle Ellis. Instead of dividing the world into classical biomes (savanna, rainforest, woodlands, tundra, etc.), Ellis conceived of depicting a map of “anthromes” to describe the way human have reshaped the earth’s ecological patterns. The Anthrome map shows croplands, rangelands, urban areas and other human settlements.
Understanding Carrying Capacity
Human population, now nearing 8 billion, cannot continue to grow indefinitely. 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. However, it is very difficult for ecologists to calculate human carrying capacity. Humans are a complex species. We do not reproduce, consume resources, and interact with our living environment uniformly. Carrying capacity estimates involve making predictions about future trends in demography, resource availability, technological advances and economic development.
Our Ecological Footprint
One way to address the challenges associated with making future projections is to look at current human impact on the planet. The ecological footprint is a measurement of the anthropogenic impact on earth. It tracks how much biocapacity (biological capacity) there is and how much biocapacity people use by comparing the rate at which we consume natural resources and generate waste to the planet’s ability to replenish those resources and absorb waste. Today, our global footprint is in overshoot. It would take 1.75 Earths to sustain our current population. If current trends continue, we will reach 3 Earths by the year 2050.
Where Do We Grow From Here?
Our planet does not have the biocapacity to sustain our current levels of growth and resource consumption. So, what can be done to minimize our collective impact on the environment? In his book, How Many People Can the Earth Support?, mathematical biologist Joel Cohen classifies current solutions into three paradigms: those looking for a “bigger pie” (improving technology), those advocating for “fewer forks” (slowing population growth), and those looking to rationalize and improve decision-making though “better manners” (changing global culture). Cohen argues that, standing along, each paradigm is necessary in solving our environmental crisis, but not sufficient. Change must come from a combination of all three. “Promoting access to contraceptives, developing economies, saving children, empowering women, educating men, and doing it all at once,” he writes, is a way to both lower our impact on the planet and improve the quality of life for all. Perhaps Oxford economist Robert Cassen said it best, “Virtually everything that needs doing from a population perspective needs doing anyway.” Adopting human-centered initiatives targeted at addressing both population growth and consumption habits, ranging from the individual to trans-national level, are our best hope for achieving a sustainable future.
Human Population 1 CE – 2050 CE
FAQs
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.
Can Earth support 12 billion? ›
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.
Do you think the worldwide population has already reached its carrying capacity? ›
As Gerland explained, "Right now the scientific consensus is that the population of the world will reach a peak some time later this century. The world population is projected to reach 10.4 billion people sometime in the 2080s and remain there until 2100, according to the United Nations Population Division.
What happens when a population is at carrying capacity? ›
As the population nears the carrying capacity, population growth slows significantly. The logistic growth model reflects the natural tension between reproduction, which increases a population's size, and resource availability, which limits a population's size.
What is the world's current carrying capacity? ›
Carrying capacity is not a fixed number. Estimates put Earth's carrying capacity at anywhere between 2 billion and 40 billion people [source: McConeghy].
What is the carrying capacity of one Earth? ›
Attempts to define an upper limit of the number of people that the Earth could support are inevitably subject to considerable uncertainty, however, the greatest concentration estimates falls between 8 and 16 billion people — a range we are fast approaching.
What population can Earth sustain? ›
On October 18, 2023, the International Union for the Scientific Study of Population (2023) broadcast a Yes-or-No debate on the statement: “The population of humans that can be supported sustainably on the planet at a reasonable standard of living is below 4 billion.” Here is an abridged version of Joel E.
What is the max capacity for Earth? ›
Earth's capacity
Many scientists think Earth has a maximum carrying capacity of 9 billion to 10 billion people.
How many humans could fit on Earth? ›
On? The land area of the Earth is about 150,000,000 square kilometers, or 150,000,000,000,000 square meters. We could perhaps squeeze three people into each square meter, so we might perhaps fit 500,000,000,000,000 people on the land surface of the earth.
How many people can the US sustain? ›
The US has a population density of 85 per square mile. We have one of the emptiest countries in the world. The area of the US is 3.8 million square miles. We could take in about 80 million people and still be well below the world average for population density.
If a population exceeds carrying capacity, the ecosystem may become unsuitable for the species to survive. If the population exceeds the carrying capacity for a long period of time, resources may be completely depleted. Populations may die off if all of the resources are exhausted.
How much longer can Earth support life? ›
So how long does Earth have until the planet is swallowed by the sun? Expected time of death: several billion years from now. But life on Earth will end much, much sooner than that. Earth will become unlivable for most organisms in about 1.3 billion years due to the sun's natural evolution, experts told Live Science.
At what age are most oysters dead? ›
It is estimated that by age three, 80 percent or more of a single oyster year class in a high disease area (like the Virginia portion of the Bay) will die due to disease.
Is there a carrying capacity for humans? ›
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 is a real life example of carrying capacity? ›
Deer feed on all sorts of plants, trees, shrubs, flowers, and grass, and require large quantities of such vegetation to sustain themselves. Eventually, deer began to starve because their large numbers depleted their main source of food; they had reached their carrying capacity.
What is the current carrying capacity of the human population? ›
Recent estimates of Earth's carrying capacity run between two billion and four billion people, depending on how optimistic researchers are about international cooperation to solve collective action problems.
Is the carrying capacity of the Earth limited? ›
THE LIMITING FACTOR
Hence it is clear the demands for food production are the greatest limiting factor for carrying capacity. The carrying capacity of earth was much higher when we modelled the proportion of land and water used by humans, but as low as 4.2 billion people when modelling food.
What is the ideal population for Earth? ›
What is the “ideal” population size? The question of what population size is environmentally sustainable has been addressed multiple times. While estimates have ranged from as low as 100 million, the most frequently occurring figure is 2-3 billion.
