Today, we are well aware that climate change is rooted in human behaviors. However, climate change is just one of the nine critical earth processes, that provide a safe operating space for humanity to grow. And all nine processes are impacted by the unintended, unpleasant effect of our behaviors.
Johan Rockstrom by the Stockholm Resilience Centre identified nine critical Earth Processes (including climate change) that are fundamental for humanity to thrive. Conceptually, they are boundaries, not tipping points. They work like body temperature or blood pressure for individuals.
When body temperature stays within some limits, such as 35-36,9C individuals are in the best conditions to work and develop. These are safe operating spaces. If individuals operate constantly out of the limits, i.e in a fever state, or suffering hypothermia, they don’t die immediately, but the probabilities of bad events constantly increase.
Likewise, if the nine processes stay within defined limits, we are sure that we live in the best environment for humanity to thrive, grow and evolve. If one or more of the nine Earth processes jumps out of the boundaries, we are not sure anymore that humanity can grow and evolve in such an environment, and the probabilities of a mass extinction keep increasing.
The concept is today mainstream in the scientific community, see for instance the article in Nature “A safe operating space for humanity (2009)”
The Nine Processes
The nine critical earth processes are:
1. Stratospheric Ozone Depletion. That’s the Ozone layer sitting in the stratosphere between 15-20 km above the heart. It protects us from solar ultraviolet radiation. In 1987 the Montreal Protocol banned CFC production and use, identified as one of the main drivers of ozone depletion, and the earth process largely improved. Humanity is not exceeding this boundary today.
2. Atmospheric Aerosol Loading. That’s the overall particulate concentration in the atmosphere. Target values are still to be determined
3. Ocean Acidification. This process consists of the decreasing of the PH values of the oceans, due to the CO2 increase in the atmosphere. ocean acidification is impacting the whole marine ecosystem, starting from coral bleaching and making marine forms of life weaker and more susceptible to diseases.
4. Biogeochemical Flows. These can be defined as two sub-processes:
4.a) Anthropogenic Nitrogen removed from the atmosphere. In short, human activities severely altered the nitrogen cycle, impacting plant species diversity, freshwater acidification, and eutrophication of marine systems. Here, it seems we are out of control. A safe boundary has been set at 62 million of tonnes per year, while we are currently at 150 million
4.b) Anthropogenic Phosphorus going into the oceans. Fertilizers, detergents, and sewage waste contribute to increasing levels of phosphorus in the oceans, impacting water pollution and excessive algae growth. The safe limit is below 11 million tonnes per year, we are currently at 22 million tonnes per year
5. Freshwater Use. Human consumption of fresh water is booming and global supply is decreasing, due to global warming, population growth, agriculture use (irrigation systems) , and industrial use (power generation, chemical processes). Clear boundaries still to be defined, but we are already experiencing a red-emergence status for hydric supply during summer in many European countries, not to mention the African ones.
6. Land-System Change. It can be defined as the percentage of forests still intact. Safe boundaries are at 75%, but we are already below that level at 62%, constantly worsening.
7. Biosphere Integrity. That’s the biodiversity loss, severely increasing during the last 50 years. Biodiversity loss is caused by the demand for food, water, and natural resources. The extinction rate is 10-100 times greater than the safe limit.
8. Climate Change. Climate change is usually measured indirectly by two leading factors: CO2 concentration (ppm per million by volume ) and increase in radiative force benchmarked with pre-industrial status. We are currently exceeding both indicators.
9. Chemical Pollution. That’s the concentration of new chemicals and other novel entities in the environment. It’s increased 50-fold since 1950, definitively exceeding safe boundaries.