As a consequence of the impact that we as humanity are having on the planet and its balance, an international team of scientists updated The planetary boundary framework and has identified that of the nine processes that are critical to maintaining stability and Earth's resiliencesix have already been exceeded.
"The Earth is now well outside safe operating space for humanity," the scientists state in the paper published by the journal Science Advances.
The nine critical processes for the Earth are:
- Climate change
- Biosphere integrity
- Novel entities (microplastics, pesticides, nuclear waste, etc.)
- Earth system change
- Fresh water
- Biogeochemical flows
- Ocean acidification
- Aerosol loading in the atmosphere
- Depletion of stratospheric ozone
The first six processes on this list have already exceeded the limits, while the first six processes on this list have already exceeded the limits, while the first six processes on this list have already exceeded the limits. ocean acidification is about to be surpassed and the aerosol loading already exceeds the limit in some regions. The levels of stratospheric ozone have recovered slightly.
"From global warming to the biosphere and deforestation, from pollutants and plastic to the nitrogen and freshwater cycles: six of nine planetary boundaries are being crossed, while pressure on all boundary processes is increasing," the research highlights.
Johan Rockströmdirector of the Potsdam Institute for Climate Impact Research (PIK) and co-author of this research, states that this update on the planetary boundaries clearly shows a patient who is not well, as the pressure on the planet increases and vital limits are crossed.
"We don't know how long we can continue to transgress these key limits before the combined pressures lead to irreversible changes and damage," warns the also professor of environmental science at Stockholm University's Stockholm Resilience Center.
The objective of The planetary boundary framework is to delineate and quantify the levels of anthropogenic disturbance that, if respected, would allow the Earth to remain in a Holocene-like interglacial state.
The Holocene period began at the end of the last ice age and was characterized by relatively stable and warm planetary conditions that enabled the evolution of agriculture and modern civilizations. Human activities have now taken the Earth out of the Holocene window of environmental variability, in what is known as the Anthropocene era.
The research clarifies that while transgressing a boundary does not equate to drastic changes that occur overnight, together they mark a critical threshold for increasing risks to people and the ecosystems of which we are a part.
"We can think of the Earth as a human body and planetary boundaries as blood pressure. Over 120/80 does not indicate a particular heart attack, but it does raise the risk, and that is why we are working to reduce blood pressure. The ozone depletion limit was exceeded in the 1990s, but thanks to global initiatives, catalyzed by the Montreal Protocol, this limit is no longer breached," says lead author Katherine Richardson, professor of biological oceanography and leader of the Center for Sustainability Science at the University of Copenhagen.
Signs of declining planetary resilience on the rise
With the stability of the Earth compromised by exceeding the planetary boundaries in six of the nine critical processes, the climatic phenomena are more extreme and affect everyone, but most worrying are the increasing signs of decrease in planetary resilienceJohan Rockström points out.
"(This) brings us closer to tipping points and closes the window on any possibility of maintaining the 1.5°C planetary climate limit," he says.
The research highlights that the results of this model demonstrate that one of the most powerful means humanity has at its disposal to combat the climate change is to respect the limits of earth system change.
"Returning total global forest cover to late 20th century levels would provide a substantial cumulative sink of atmospheric CO2 in 2100. However, this reforestation seems unlikely, given the current interest in biomass as a substitute for fossil fuels and the creation of negative CO2 emissions through bioenergy with carbon capture and storage," the research explains.
Both activities are already serving to increase pressure on the Earth's remaining forest area. However, our study indicates that failing to respect the planetary boundary of Earth system change can potentially jeopardize efforts to achieve the global climate objectives adopted in the Paris Agreementhe stresses.
This new evaluation of the planetary boundaries not only underscores the close and complex links between people and the planet, but provides a basis for more systematic efforts to protect, recover and rebuild Earth's resilience.
Source: Stockholm Resilience Center