Planetary boundaries are a framework to describe limits to the impacts of human activities on the Earth system. Beyond these limits, the environment may not be able to continue to self-regulate. This would mean the Earth system would leave the period of stability of the Holocene, in which human society developed.
These nine boundaries are:
- Climate change,
- Ocean acidification,
- Stratospheric ozone depletion,
- Biogeochemical flows in the nitrogen cycle,
- Excess global freshwater use,
- Land system change,
- Erosion of biosphere integrity,
- Chemical pollution, and
- Atmospheric aerosol loading.
