In this guide, we outline:
– What carrying capacity means
– What the potential carrying capacity of Earth is right now, and also in the future
Summary – Carrying Capacity Of Earth
What Carrying Capacity Means
An unofficial definition of carrying capacity might be the maximum population size that an environment can sustain with it’s available resources
Other sustainability related concepts that might be used in conjunction with carrying capacity might be the concepts of planetary boundaries, and ecological footprints
How Carrying Capacity Might Be Assessed
Carrying capacity obviously differs between different geographic locations
Carrying capacity really needs to be broken down specifically to the geographic area (for example a town, city, region or country), the type of resource, the assessed time span, and other relevant factors.
Having said that, there are some global issues and factors that can make carrying capacity a globally assessed metric in some ways too – we list these factors in the guide below
Factors That Might Impact Carrying Capacity
Different factors like population size (and human overpopulation), rate of resource production, rate of resource replenishment, rate of consumption, and waste and environmental degradation can all impact carrying capacity
We list some other factors and variables that might impact carrying capacity in the guide below
There can also be variables that change carrying capacity over time, such as advancements in technology, which might help augment the supply of a particular resource (desalination’s augmentation of freshwater supplies in some cities might be one example of this)
Technology advancements can actually increase carrying capacity
What Is The Current Carrying Capacity Of Earth Right Now?
This might be too broad of a question
If we look at one singular type of resource, some estimates indicate we currently produce enough food to feed 10 billion people globally, but some regions still suffer from hunger and malnourishment
Instead, we might ask what the carrying capacity of different cities and towns are
It might be accurate to say that some cities around the world comfortably supply their population with the basic resources to live
Other cities and towns, particularly in developing or less developed regions in the world, lack the basic resources like fresh water and food, which creates water and food security issues
The Potential Future Carrying Capacity On Earth
Carrying capacity in the future might be broken down and identified for each city
However, the future carrying capacity of individual cities and the world as a whole might be impacted by technology changes and advances, whether or not lifestyle and consumer choices stay the same, a changing climate, and other variables
Future Trends To Expect With Demand & Consumption
The world population is expected to increase in the future, and there’s expected to be an increase in the demand and consumption of food, energy, and fresh water, along with other important resources
Resource intensive products like meat and fossil fuel may increase in total demand
An Estimate Of The Earth’s Ideal Carrying Capacity According To One Source
An estimate of the carrying capacity of Earth according to one source:
A world population of around a billion would have an overall pro-life effect.
This could be supported for many millennia and sustain many more human lives in the long term compared with our current uncontrolled growth and prospect of sudden collapse
Via the undark.org resource listed, they note that the Global Footprint Network calculates that humanity is currently exceeding Earth’s sustainable productivity by 60 percent.
This number may also be useful in getting an estimate of where Earth’s true carrying capacity might be.
For example, we could calculate what 60% of the current global population is, or calculate what consumption total 60% of our current consumption total is, to get an idea of how many people the world can sustainably hold, or how much the current population can sustainably consume.
Sustaining The Population In The Future – Some Considerations
Some of the things that may contribute to a sustainable population in the future might include, but isn’t limited to:
– Sustainable consumption rates (including but not limited to reducing consumption, becoming more efficient with consumption, and consuming more resource efficient products)
– Considering how alternative products and services might play a part, such as alternative energy, alternative transport, alternative food production, substitutes for metals, and so on
– Managing a changing climate
– Preventing environmental degradation, and the endangerment or extinction of certain wildlife and plant species in some locations
What Does Carrying Capacity Mean? – A Definition
A definition of carrying capacity when it comes to humans might be:
– Carrying capacity is the maximum number of people that can be supported and sustained in a specific geographic area (which has a local environment or ecosystem)
However, that definition also has conditions and qualifiers such as:
– Sustaining and supporting a population requires the necessary resources (like food and water as two example) to be used in a sustainable way (within their sustainable limits, and to not be depleted), and to prevent environmental degradation beyond a certain point. Resource abundance and availability, and environmental health are key consideration here
– Social, cultural and economic factors play a role in supporting and sustaining a population too
– Carrying capacity is not fixed. It can be changed by a number of factors, such as population increase, a change in consumption habits and demand, an advance in technology, or a number of other factors
Assessing Carrying Capacity On The Local Level vs The Global Level
Carrying capacity might be more accurately calculated or assessed on local scales i.e. for individual different cities and countries
This is because each city and country has different means to produce certain resources, and different means to access different resources.
For example, some cities have more naturally occurring freshwater supplies than others, and some cities have better financial means to generate new fresh water from technology like desalination, just as one example
Having said that, international trade (imports and exports) does add a global component to carrying capacity considerations.
There are also other factors that can make carrying capacity a global consideration, such as immigration and immigration between countries, and the possibility that all countries might contribute to a changing climate, which may have an impact on the production of resources for all countries (in the case of rainfall for fresh water, and the climate for agriculture, just as two example).
Carrying Capacity As A General Concept, & Not A Definitive Number
Some sources indicate that carrying capacity is a general concept that can be difficult to estimate.
As such, it might be used as a general guide only, and not a definitive number (due to the difficulties, complexities and variables associated with the estimation)
Carrying capacity is a quantitative concept that [can be] difficult to estimate … (sciencedirect.com)
What Is The Carrying Capacity Of Earth Right Now?
There might not be any one definitive answer to this question.
Instead, we’ve discussed some factors below that might be important when considering carrying capacity:
Population Right Now
As of 2019, the population on Earth was around 7.7 billion people.
Resource Availability To Sustain The Population Now
We haven’t officially run out of any key resources yet worldwide.
But, certain cities/towns and places have experienced short term resource shortages, such as Cape Town with their freshwater shortage
It’s also important to note that we have experienced an uneven distribution of certain resources worldwide, or, some regions can experience resource access and resource security issues (such as water security and food security).
Freshwater is a resource that is naturally unevenly distributed throughout the world, with some countries being much drier and have much smaller natural supplies than others.
Having said that, some places have freshwater supplies, but yet, hundreds of millions of people still go without access to clean water for drinking and basic household activities – due to water pollution, poverty, lack of water and sanitation infrastructure and global inequality issues.
Using food as another example – there is currently as unequal distribution of food in different regions.
We currently produce enough food for around 10 billion people globally, but people still go without access to food around the world and go hungry or even die of malnutrition.
Developing countries face many more problems than developed countries in feeding their people due to factors like a lack of industrial farming practices and technology, and a lack of cold storage to prevent food waste.
Different food diet types may also have different carrying capacities.
Poverty is also a big issue.
So, we are supporting some people in the world with the different resources available, but not others. Carrying capacity can’t be analysed by just looking at one resource – it takes a range of resources to run a society.
Resource Consumption Rates
Western countries and cities tend to consume much more per capita than developing countries and cities right now.
A common way the West might over-consume is via food diets – eating diets high in animal products (meat and dairy), calories, and processed foods
But, increasing industrialisation of developing countries means there will likely be more consumption in these countries too, especially of energy and fossil fuels.
The ecological footprint of a country is one way of measuring very roughly how wasteful a country is, or how many natural resources they use
Environmental Degradation, & Environmental Sustainability Right Now
The environment is already showing some signs of degradation in 2019.
Some of this degradation is reversible, whilst some may not be.
Just as a few examples include but aren’t limited to:
Around a third of the world’s land is in a degraded state, with soil erosion being a problem for the topsoil we use to produce food on farms
Fertilizers and pesticides present a range of pollution issues
Deforestation and land clearing issues
Some fisheries are collapsing, or have collapsed, and the ocean is warming (with various forms of wildlife dying off in some parts of the ocean)
Air quality and air pollution levels are poor or hazardous in some cities across the world
Water pollution and contamination is severe in some major countries across the world due to different reasons like dumping wastewater, sewage and industrial waste directly into open water sources (amongst other issues)
The world as a whole has experienced almost 1 degree of temperature warming since pre industrial times
… So, land and soil, air, and water (salt/marine and fresh) are all being depleted at different rates in different parts of the world.
Animals, and plant life (forests, trees and vegetation) are also being depleted, and biodiversity loss is an issue, in some regions around the world
What One Source Indicates About Current & Past Ecological Degradation
Undark.org (URL in the resources list) has put together a good article explaining how advances in processes and technology relating to increased resource production or extraction always have ecological degradation consequences.
What they note is that right now, we are exceeding the safe limit for 4 planetary boundaries – climate change, land system change, biochemical flows and biosphere integrity.
They note that apart from invasion, over extension of an empire and natural climate change, in cases where societies depleted forests, fisheries, freshwater, or topsoil, the consequences were dire.
What Is The Carrying Capacity Of Earth In The Future?
Population In The Future
The world’s population is expected to grow to somewhere between 9 to 13 billion heading up to the year 2100.
Resource Availability To Sustain The Population In The Future
We’ve written a few guides about specific resources we might be running out of in the future, and whether we actually will run out of resources in the future:
What Resources Are We Running Out Of On Earth, & How Much Do We Have Left?
Will We Run Out Of Resources On Earth In The Future, & What Will Happen If We Do?
Some things that are clear from these guides are:
– Freshwater & Drinking Water
Fresh water management by different cities will be critical in the future.
We need to be more efficient with, and manage water better, especially when it comes to water use in agriculture and for industry & power generation.
Severe droughts and decreasing rainfall in some parts of the world can compound this problem.
Factors such as degradation of land and erosion of topsoil, a lack of water for irrigation, and poverty in developing countries could impact the extent to which we produce food in the future.
There’s only so far that industrial agriculture can take us, with yields already showing signs of annual decrease for major crops.
Becoming more efficient with farming and our diets will be key areas we can ensure we have enough food for the future.
Some technologies such as lab grown meat are also being proposed by some parties as part of the long term solution
We will have more energy in the future, but it’s a question of how much is produced, where it’s produced, and by which methods i.e. fossil fuels vs renewables.
Each energy source has it’s own set of pros and cons to consider
– Arable Land & Topsoil
We are already near capacity with using total arable land available in developed countries, and topsoil might have around 60 harvests left on average.
– Breathable Air
Oxygen production by phytoplankton (influenced by the temperature of the ocean), and air pollution are critical to having breathable air in the future.
– Metals, Minerals & Precious Metals
Similar to fossil fuels, these resources are showing signs of having decades or even hundreds of years of supplies left.
Some metals and minerals are depleting quicker than others.
These two interesting guides also discuss why we might never run out of mined resources, and factors that can impact the supply of mined resources
Environmental Degradation, & Environmental Sustainability In The Future
All of the environmental degradation issues we outlined above could persist or get worse in the future if more sustainable environmental practices aren’t implemented, or restoration of the environment isn’t a priority.
We definitely need to do more to protect the environment, natural resources, wildlife, plant life and biodiversity heading into the future if we want to maintain or increase our carrying capacity.
Planetary boundaries are one set of boundaries that have been proposed to stay within if we want an Earth system that can maintain it’s stability and resilience.
Variables & Factors That Could Impact Earth Carrying Capacity In The Future
Some of the variables and factors that might impact carrying capacity might include, but aren’t limited to:
– Population size (and human overpopulation)
– Consumption rates, and level of demand by consumers. Lifestyle and consumer choices will play a role here
– How resource intensive or resource efficient our consumption is – for example, meats and fossil fuels are said to be resource intensive according to some sources. Some food diets are also more water and land efficient than others
– Level of production
– Management of waste from production (some of the worst pollutants might be synthetic fertilizers, synthetic pesticides, antibiotics, industrial waste, and fossil fuel emissions (from energy generation and vehicles))
– Our ability to re-use, recycle, repair and recover resources in the future (a more circular economy might be a factor)
– Sustainability measures put in place to protect the environment, the different ecosystems (wildlife, plant life and micro organisms for example), and certain resources against degradation (such as water, air, and land/soil)
– Advances in technology that allow resources to be used more efficiently, increase the usable supply of specific resources in a practical way (augment and increase supply), or, allow resources to be extracted or generated more economically
What is interesting to note is that 9000 years ago it took 6 times as much land to grow food for one person as it does now – so this shows how humans have advanced (fastcompany.com).
Having said that, industrial agriculture is responsible for a lot of land degradation, soil erosion (topsoil loss), fertilizer pollution, pesticide pollution, decrease in biodiversity, deforestation and land clearing, and yields for major crops have decreased annually in some parts of the world recently.
So, advances in production capability aren’t without environmental degradation and other types of downsides.
– Whether or not alternatives and substitutes can be used for certain resources e.g. researching and coming up with alternatives for certain metals and alloys we might use
– The impact of a changing climate on aspects of society like agriculture
– The impact of significant events factors on society like natural disasters, AI, war and conflict, a pandemic or biological disaster, and so on
Other Considerations For Carrying Capacity in The Future
– To an extent, the population, the economy and society as a whole is going to adapt to resource supply changes
For example, if a certain resource becomes more scarce, that resource is going to become more expensive, so less people will be able to afford it, or people will use less of it.
Economic systems can be self correcting in this sense.
– Availability of total resources or all resources is sometimes not the key thing to track in terms of resource depletion.
What we might track first and foremost are the most important resources that are scarcest.
For example, that resource could be freshwater and drinking water.
Not only could lack of freshwater or drinking water do the most harm and damage to humans, the local economy and the environment in one particular area, but a depletion of freshwater has a domino effect on the availability of other resources such as food and energy – both of which require water for irrigation and cooling respectively to produce.