What are the Earth’s Limits and Planetary Boundaries?

Introduction.

What rules are needed to protect the Earth’s environment? Recently, the world is facing problems such as a changeable climate, a decrease in the number of animals and plants, and a shortage of water. A system called “Planetary Boundary” was conceived to solve these problems. By learning about this system, we can learn what we can do to protect our planet.

The Earth’s nature is an essential part of our lives. However, as this nature gets more and more damaged, it will become a difficult world for us to live in as well. Therefore, we need to start working now to protect our environment as soon as possible. The Planetary Boundary is a guidepost for such efforts.

What is the Planetary Boundary?

The Planetary Boundary is a set of rules that defines the extent to which we can safely use the Earth’s environment without damaging it. These rules were derived from scientific research into how the Earth system works. For example, the rules specifically calculate the extent to which climate change and biodiversity loss will exceed the Earth’s ability to adjust. The Earth creates an environment in which people, animals, and plants can live comfortably by maintaining a balance of temperature, water, and air. Nine items were created to protect this system.

This idea was first presented by scientists in 2009. They determined the limits of how much the Earth can be burdened by the environment before it breaks down. By adhering to these rules, we can create a world where future generations can live in peace.

Furthermore, the Planetary Boundary provides important guidance not only to scientists, but also to governments, corporations, and us, the general public. Based on these rules, we can consider concrete actions to protect the global environment.

Nine Items in the Planetary Boundary

The following table shows the nine items of the Planetary Boundary and a brief description of each.

Item	Contents
Climate Change	Ensure that the earth does not become too hot. The key is to reduce carbon dioxide emissions.
Biodiversity loss	Protecting plants and animals from extinction. It is important to protect ecosystems.
Land use change	Avoid losing too much forest and nature. Need to maintain the balance of nature.
Freshwater use	Do not overuse or pollute water in rivers and lakes. Ensure that water is available for all living creatures.
Ocean Acidification	Ensure that the acidity of the oceans does not increase. Can be protected by reducing carbon dioxide.
Atmospheric aerosol load	To prevent too many small particles in the air. Needs attention as it affects climate and rainfall.
New chemicals	Ensure that newly created chemicals do not have a negative impact on nature.
Nitrogen and phosphorus cycle	Do not use too much nitrogen and phosphorus used in fertilizers and other products. Ensure that this does not affect water and soil.
Depletion of the ozone layer	To protect the ozone layer. When this is lost, ultraviolet rays become stronger and have a negative impact on people and nature.

These rules are very important to protect the earth’s environment. Next, we will look at each of these items in a little more detail.

Climate Change

One of the causes of climate change is the increase of carbon dioxide in the air. As this increases, the earth becomes hotter and hotter, and typhoons and heavy rainfall may increase. Reducing carbon dioxide emissions can help prevent this problem.

Climate change also affects the frequency and magnitude of natural disasters. For example, increased flooding and droughts will make life and economic activities more difficult for people. Therefore, in addition to reducing carbon dioxide emissions, the use of renewable energy sources is required.

Loss of Biodiversity

Biodiversity refers to the variety of plants and animals on the planet. When this is reduced, the balance of nature is disrupted. For example, if an animal goes extinct, not only will the plants that depend on it not be able to grow, but the other animals that eat it will not be able to survive either. These chain effects can disrupt the entire food chain, and as a result, the entire ecosystem may cease to function.

To protect biodiversity, it is important to preserve as much of the natural environment as possible. Efforts must also be made to protect ecosystems by reducing overhunting and deforestation. Protecting biodiversity has a direct impact on our lives.

Land Use Change

When forests and nature are lost, the animals and plants that live there are in trouble. In addition, forests absorb carbon dioxide and thus play a role in preventing climate change.

The problem of the destruction of the natural environment due to urbanization and the expansion of agricultural land is particularly serious. To solve this problem, it is important to promote sustainable land use. For example, activities to replant forests and the development of technologies to use land more efficiently are needed.

Freshwater Use

Water from rivers and lakes is used in our daily lives, agriculture, and factories. However, if we use too much, other living things will not be able to use the water. It is important to use water carefully.

In addition, freshwater pollution is also a problem. When wastewater from factories and agriculture flows into rivers and lakes, it becomes uninhabitable for living creatures. Regulations to maintain water quality and the spread of technology to purify polluted water are necessary.

Ocean acidification

Carbon dioxide affects not only the air but also the oceans. Increased ocean acidity makes it difficult for corals and fish to live.

To prevent ocean acidification, we must not only reduce carbon dioxide emissions, but also work to protect the marine environment. For example, increasing the number of marine protected areas and enforcing stricter rules for fishing can help protect ecosystems.

Atmospheric aerosol load

Small particles in the air (aerosols) can affect climate and weather. For example, it is important to note that they can make rainfall more difficult.

To solve the aerosol problem, it is important to reduce emissions from factories and automobiles. Further research is also needed on the impact of aerosols on the climate.

New Chemicals

Some of the new chemicals that are being created have a negative impact on nature. It is important to control these carefully.

In particular, chemicals that remain in the environment for long periods of time can contaminate soil and water. Strict standards need to be set for the development and use of chemicals.

Nitrogen and Phosphorus Cycles

Nitrogen and phosphorus used in fertilizers help plants grow, but too much of them can pollute rivers and oceans.

To solve this problem, it is important to devise ways to use fertilizers. For example, there are techniques to use only the necessary amount or to utilize organic fertilizers.

Depletion of the ozone layer

The ozone layer protects the earth from ultraviolet radiation. As this layer thins, humans and nature suffer damage from ultraviolet rays.

Under international cooperation, efforts are underway to reduce the use of ozone-depleting substances. As a result, the ozone layer is gradually recovering.

Changes in the Planetary Boundary

Planetary Boundary has been published by the Stockholm Resilience Centre from 2009 to the present. The report provides a scientific assessment of the current state of the global environment and how it is changing. Specifically, the report measures the limits of the Earth system and analyzes the progress of problems such as climate change and biodiversity loss based on these limits. These assessments provide guidance to policy makers and the general public to better understand environmental issues and take appropriate measures.

Year	Number of rules exceeded	Major changes
2009	3	Climate change, loss of biodiversity, nitrogen and phosphorus cycles in jeopardy.
2015	4	Land use change also became dangerous and more rules to worry about.
2023	6	Freshwater use and new chemicals were also added, exceeding a total of 6 rules.

The above results show that more and more environmental problems are crossing thresholds on the planet. Currently, climate change, chemicals, nitrogen and phosphorus, freshwater, land change, and biodiversity are exceeding the Earth’s limits. Crossing the threshold increases the risk of large-scale, abrupt, or irreversible environmental change. While these dramatic changes do not necessarily occur overnight, the boundaries are undoubtedly a very important threshold that amplifies the risks to us humans and the ecosystems to which we belong.

Planetary boundaries are closely interrelated, and crossing one boundary can affect the others, resulting in deviations from the Earth’s safe operating zone. This interaction is characteristic of the complex biophysical system that is the Earth and cannot be considered a boundary in isolation.

To build a sustainable future, it is essential to respect all nine planetary boundaries and maintain a safe operating space for human civilization. Recognizing the limits that each boundary represents and acting prudently to avoid exceeding them will be the key to building a sustainable society for our future.

How can we follow the rules?

It is important for all of us to work together to follow the rules.

What Governments and Businesses Can Do

Governments and companies need to make efforts to create environmentally friendly rules and use new technologies to reduce their impact on the environment. Examples include using renewable energy and protecting forests.

Furthermore, by promoting environmental education, they can spread awareness of environmental protection to the next generation. Companies should strive to reduce their environmental impact in the manufacturing process of their products and in the selection of raw materials.

What We Can Do

Each of us can do our part. For example, we can all do our part to reduce waste by recycling and using our own bags and bottles. Shorter showers and water-saving faucets are also effective ways to avoid wasting water. In addition, it is important to choose products that are environmentally friendly, such as those with the Eco Mark or made from renewable materials. And by informing those around you about environmental issues, you can share awareness and work together.

Choosing environmentally friendly transportation and recycling thoroughly can also help. Furthermore, by participating in local cleanups and tree planting activities, you can work to protect the environment around you.

Conclusion

Planetary Boundary is an important rule to protect the earth’s environment. As it is now, many rules are in danger. We need to start acting now to protect our future Earth. Let us all work together and aim to live in a way that protects our planet.

Protecting the environment can start with the actions of each and every one of us. Even small actions, accumulated together, can make a big difference. Let’s start doing what we can do now to leave a beautiful planet for future generations.

References

1.Stockholm Resilience Centre. “Planetary Boundaries Framework”.

2.CGER, NIES. “Monitoring Global Environmental Harmony”.

3.Spaceship Earth. “Planetary Boundary”.

4.Asahi Shimbun. “Planetary Boundary Status”.

5.Richardson et al. “Earth beyond six of nine planetary boundaries” Sci. Adv. 9, eadh2458 (2023).