The nine planetary boundaries are the thresholds that humanity must not cross in order not to endanger the favorable conditions for its life on Earth. A study published April 26 in the scientific journal Nature reviews teaches us that a sixth boundary has been crossed: the freshwater cycle.
What is a planetary boundary?
The concept of planetary boundaries was theorized in 2009 by a group of 28 international scientists. As the media points out good friendit is about “of a quantitative measure of the planetary boundaries within which humanity can continue to grow and prosper”† These limits are as follows:
- climate change (crossed)
- the erosion of biodiversity (overcome)
- disruption of the biogeochemical cycles of nitrogen and phosphorus (crossed)
- the modification of terrestrial ecosystems (crossed)
- ocean acidification
- global water use (crossed)
- the depletion of the stratospheric ozone layer
- pollution by new substances (crossed)
- the increase of aerosols in the atmosphere
This is a scientific front: planetary boundaries are a matter of current research. When they express criticism, it begins to be widely taken into account by organizations and states (UN, EU, France, etc.).
The freshwater cycle
Until now, the limit on fresh water use seemed to be enforced in a ” safe area The publication of a recent study changes the situation: in addition to blue water (as a result of atmospheric precipitation, is discharged into the sea or held in lakes or other reservoirs), scientists have decided to take into account the green water. the water taken up by plants.With this new taxonomy, the boundary of freshwater has largely been exceeded.
In concrete terms, this means that the Amazon rainforest, whose sustainability depends on soil moisture, is directly threatened. Agricultural land, on which our food resilience depends, is also under pressure.
Bad news intended to warn us, but also to remind us that solutions have already been devised: including limiting artificial soil, changing our agricultural model. They are just waiting to be implemented!