The 9 Planetary Boundaries

The past 3 years I have followed a pre-master in Earth and Economy and a master in Environment and Resource Management. And up until now, I mostly wrote about sustainability and an eco-positive lifestyle in the personal sphere, as I believe that we all have a share making the earth a happy place for everybody. However, as I gained my master in science, I feel like I can also share more about sustainability on a global level. Today I am starting with the ultimate base, the 9 planetary boundaries.

The Base of Sustainability

Ultimately, the current sustainability challenge is about keeping our climate and earth as it is or reversing the damage we have done. About 12,000 years ago the earth has entered the Holocene, a period of a relatively stable climate. This climate has enabled the homo sapiens species (the only human race that is still existent today) to thrive. We still live in the Holocene today and we want it to stay this way because this climate enables us to thrive. However, we as humans have been changing the earth quite drastically, which threatens the stable state of our planet. If we cross certain thresholds, the Holocene might not be so pleasant anymore.

planetary boundaries

In 2009, a group of scientists published the concept of the ‘planetary boundaries’ (Rockström et al, Source). All research into environmental change and threats were then combined and visualized into a single concept. The scientists found that there are 9 planetary boundaries in total, which concern 9 processes on which humans may influence the earth in a negative way. That’s why the scientists have created boundaries, to make sure that we do not cross those thresholds, as it is dangerous for the human race to do so. These 9 planetary boundaries are the base of global environmental challenges.

Thresholds

From these 9 human-induced processes that can lead to environmental change and threats, the scientists were able to form thresholds for 7 of them. For the other 2 processes there are no boundaries yet. That’s because science is not ready to answer that question yet. For these processes we still have more research to do. So, we know there are 9 planetary boundaries, we just don’t know the exact threshold for 2 of those yet. And good to know, for the known boundaries there is always a range of uncertainty. We cannot say that for example, a threshold is 10. We then say something like: the thresholds lies within a range of 7-13. Environmental change comes with uncertainty.

Tipping points

There are also tipping points within most of the environmental processes listed in the 9 planetary boundaries model. Those tipping points are out of human control, it’s when planet earth takes over. One process where there are many tipping points is climate change. For example, right now, we as human are increasing the overall temperature on planet earth. However, a tipping point is the permafrost in Europe and Western Siberia. When the temperature reaches a certain temperature there, the permafrost will melt, releasing huge amounts of methane, which then increase the temperature even more. Once a tipping point is reached, there is no going back. The tipping points are also relatively uncertain, so we should stay away from the planetary boundaries.

The 9 Planetary Boundaries

These are the 9 human-induced processes for which scientists have formulated planetary boundaries:

1 Climate Change

2 Novel Entities

3 Stratospheric Ozone Depletion

4 Atmospheric Aerosol Loading

5 Ocean Acidification

6 Biogeochemical Flows

7 Freshwater Use

8 Land-System Change

9 Biosphere Integrity

The 9 Planetary Boundaries

Current Situation

The picture that I included above is the most current version, from 2022. Before 2022, the boundaries ‘novel entities’ was not known yet, now it is. The thresholds for atmospheric aerosol loading and biosphere integrity are partly or entirely unknown still. From the 7 known boundaries, 4 are crossed and 3 are not. The green inner circle in the figure above is the safe operating space for humanity, when the dotted line is crossed we’re in the red and have passed the threshold.

I will tell you more about the 9 planetary boundaries in this series. Consequently, I will dedicate a full blogpost about each known boundary to tell you more about it. I have written once before about ocean acidification, but I might delete that post as I want to alter it a lot, and write a new one. After this series, you’ll know all about environmental change and sustainability on a global level!

Had you ever heard about the 9 planetary boundaries before?

Yours sincerely,
Romee

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