The Planetary Boundaries
The *Planetary Boundaries Framework* is a scientific concept that identifies nine critical Earth system processes that regulate the stability and resilience of the planet . The framework proposes quantitative boundaries for these processes, within which humanity can continue to develop and thrive for generations to come. The nine processes are:
1. Climate change
2. Biodiversity loss
3. Biogeochemical flows (phosphorus and nitrogen cycles)
4. Land-system change
5. Freshwater use
6. Ocean acidification
7. Stratospheric ozone depletion
8. Atmospheric aerosol loading (microscopic particles in the air)
9. Introduction of novel entities (e.g., plastics).
The framework provides a systems view of the Earth system and presents an international and long-term context for national policy setting. It can be used as a benchmark for measuring progress towards environmental goals. The planetary boundaries concept has generated enormous interest within science, policy, and practice since its inception in 2009.