The 9 planetary limits: how many have we exceeded?

The history of planetary limits

Earlier this year, scientists highlighted the fact that a fifth planetary limit had been reached, linked to the proliferation of chemicals and plastics in our environment. Olivier Fontan, former director of the High Council for the Climatetragically spoke of the asphyxiation of our planet by these synthetic materials. Shortly afterwards, a new study highlighted the dangers threatening the freshwater cycle.

In 2009, a team led by Johan Rockström at theStockholm Resilience Center developed the concept of a “planetary limit”. These limits define the thresholds that our planet can tolerate before entering a phase of instability, or even ecological catastrophe. These limits were designed to preserve a stable state, that of the Holocene, which lasted for more than 10,000 years. However, at the dawn of 2022, six of these nine limits have been crossed.

These researchers have identified nine key areas that require particular attention:

  • Climate change

  • Biodiversity and ecosystem integrity

  • Biogeochemical cycles of nitrogen and phosphorus

  • Fresh water resources

  • Integrity of the ozone layer

  • Ocean acidification

  • Changes in land use

  • Air pollution

  • Chemical contamination