planetary boundary

The "Planetary Boundaries (PBs) diagram visually represents the current status of the nine PB processes that regulate our planet's health. Each process is quantified by one or more control variables based on observational data, model simulations and expert opinions." 2025. 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, the erosion of biosphere integrity, chemical pollution, and atmospheric aerosol loading.