August 19, 2022


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Climate, biodiversity, chemical pollution … we have now crossed five planetary boundaries

In 2009, the director of this Swedish center, with a team of about thirty eminent researchers, attempted to conceptualize and model the boundaries of key terrestrial biophysical systems. A broader plan is to consider these systems as a whole, i.e. to state the planetary scale and define the standard baseline.

Because if human civilization has been able to develop to this extent for the last thousands of years, for the last ten thousand years, we have been living through an incredibly stable period called the Holocene. In other words, the environment, the climate, combined with exceptionally stable conditions compared to the past of our planet. But this “state of grace” has now been compromised by the growth of our species, which has brought the earth into a new, anthropological era. Human activities and activities are an era that affects the balance of vital climate, biological and bodily systems.

Safe place for human development

From this work emerges the definition of the nine planetary boundaries, and the concept of a safe place for human development (“safe operating space”), i.e. conditions such as the Holocene. For each major Earth system, scientists have determined which variables can tell us when we cross the planetary boundary. Most of them are well known to the general public:

  • Climate change, in particular, is estimated by the concentration of CO2 in the atmosphere
  • Biodiversity loss is measured by the extinction rate of the organism
  • Cycles of nitrogen and phosphorus
  • Ozone concentration in the stratosphere
  • Ocean acidification
  • Use of fresh water
  • Land use and conversion to agricultural land
  • Aerosol load in the atmosphere
  • Chemical pollution
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For such global and interconnected systems, it is important to understand why we are talking about not crossing a threshold, and not about the gradual evolution of effects. In fact, these systems do not react in a linear way to uprisings: they tend to stay afloat and gain money, despite increasingly strong imbalances, until they reach a turning point. Beyond a certain limit, it is almost impossible to break the balance and return to the starting position. This is an irreversible point.