6.2.8—Climate change planetary boundary
- Syllabus
- First assessment 2026
- Objective
- 6.2.8
- Level
- SL
Treat a Boundary as Rising Risk, Not a Local Tipping Point
The climate-change planetary boundary is a proposed safe-operating-space limit for Earth-system pressure; published evidence suggests that this boundary has already been passed.
Evaluate which climate indicators and control variables the source uses, the reference period, spatial scale and uncertainty. Transgression means rising systemic risk, not a guaranteed date of collapse.
If an assessed climate indicator lies beyond its proposed safe range, that supports boundary transgression; a separate mechanism and local evidence are still needed to claim that a particular ecosystem has crossed a tipping point.
Report the source, indicator definition, threshold method and uncertainty before accepting or challenging the assertion.
Boundary transgression is not synonymous with certain irreversible collapse.