In this guide, we look at what carrying capacity might be defined as.
We also look at the potential carrying capacity of the earth both now, and in the future.
Carrying Capacity Definition
First, let’s define what carrying capacity actually is …
Here are two different definitions of carrying capacity:
- The carrying capacity of a biological species in an environment is the maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water, and other necessities available in the environment.
- Carrying capacity is a quantitative concept that assumes the limit, though difficult to estimate, of the ability of natural ecosystem to support continued growth of population within the limit of abundance of resource and within the tolerance of environmental degradation.
So, as an outline, carrying capacity might be summarised as:
- an estimation of the population size the world can sustain, with consideration of the abundance of resources to support that population, and also considering environmental degradation
- it is only an estimation given the difficulties, complexities and variables associated with the estimation (it’s not a precise number)
Population size (the growth of, and/or maximum population size), resource availability, and sustaining a healthy environment are keys.
What Is The Carrying Capacity Of Earth Now?
Population Right Now
As of 2019, we have an estimated 7.7 billion people on Earth.
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 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.
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 – we produce food. 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. Poverty is also a big issue.
So, we are supporting some people in the world with the resources available, but not others.
Environmental Degradation, & Environmental Sustainability Right Now
The environment is already showing major signs of degradation in 2019. Just as a few examples:
- 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 are issues
- Fisheries are collapsing and the ocean is warming (with various forms of wildlife dying off)
- Air quality is poor or hazardous in some cities across India, China, the Middle East and Africa
- 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 (such as bees), and plant life (forests, trees and vegetation) are being depleted, and biodiversity loss is an issue.
We could definitely be doing a better job right now of not degrading the environment in different regions across the world.
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. They also note that in terms of land and water resource usage, the Global Footprint Network calculates that humanity is currently exceeding Earth’s sustainable productivity by 60 percent.
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:
- Will We Run Out Of Resources On Earth In The Future, & What Will Happen If We Do?
- What Resources Are We Running Out Of On Earth, & How Much Do We Have Left?
Some things that are clear are:
- Freshwater & Drinking Water – this will be absolutely critical going forward if we are to prevent water shortages. 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.
- Food – 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.
- Energy – we will have more energy in the future, but it’s a question of how much is produced and by which methods i.e. fossil fuels vs renewables. We still need to invest more heavily into renewables to provide a greater share of overall energy output.
- Arable Land & Topsoil – we are already near capacity with using total arable land available in developed countries, and topsoil has 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.
Environmental Degradation, & Environmental Sustainability In The Future
All of the environmental degradation issues we outlined above could be in a critical or severe state by the year 2100.
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.
Notes On Carrying Capacity
- Carrying capacity is less an Earth wide thing, and is more a location based thing i.e. different cities and countries are going to have different supplies of different resources, and access to those supplies. For example, some cities have more sustainable freshwater and drinking water supplies than others
- Western countries and cities tend to consume much more than developing countries and cities. But, increasing industrialisation of developing countries means consumption, especially of energy and fossil fuels, will increase consumption. A common way we over consume in the West is via our diets – eating diets high in animal products (meat and dairy), calories, and processed foods
- Exporting and importing resources is one way of moving resources from a resource abundant place to a scarce one. Although, this is not always possible for all resources
- 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
Variables & Factors That Could Impact Earth Carrying Capacity In The Future
- Our total consumption rate/demand of resources
- The types of resources we actually consume e.g. changing our diet to a more land and water efficient diet could increase food production efficiency significantly in the future
- Fertility rates worldwide and country wide
- An increasing population is naturally going to increase demand of most resources
- To an extent, the population, the economy and society as a whole is going to adapt to resource supply. 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. Society can be self correcting to a certain extent
- External factors like severe weather events (droughts, floods etc.) and an increasing global temperature are going to decrease the supply of certain resources in different locations. Pollution and degradation of water, air, and land/soil are other examples of external factors. Some of the worst pollutants are fertilizers, pesticides, antibiotics, industrial waste, and fossil fuel emissions (from energy generation and vehicles)
- Our ability to reduce resource usage in the future, or change our consumption habits to become more sustainable from a supply and environmental degradation perspective
- Our ability to re-use, recycle, repair and recover resources (have more of a circular economy and minimise waste or be more efficient with our waste) in the future
- Our ability to come up with technology that helps us use resources more efficiently, create and deliver it a different way, or increase/augment our supply of a specific resource e.g. desalination which can help us augment water supplies by turning salt water into freshwater. Other examples are fossil fuels moving towards nuclear and renewable energy, eating lab grown food and meat and more. 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.
- Our ability to come up with alternatives to certain resources e.g. researching and coming up with alternatives for certain metals and alloys we might use
- Disasters like natural disasters, an AI war or takeover, a pandemic or biological disaster, nuclear war, a changing climate
- Wildlife, plant life and micro organisms are very important to natural resource production and regulation of the environment
- 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.