A planetary boundary is an ecological threshold that, if breached, can lead to dangerous and potentially irreversible environmental change. The boundaries indicate the "safe operating space for humanity" and are set through an Earth system science-informed process. These boundaries are important for humanity’s continued wellbeing and for reducing the risk of crossing thresholds that lead to significant environmental degradation. They form an important tool for understanding global environmental change, providing guidance for effective management, and providing a framework for international negotiations on environmental sustainability and stewardship.

See also: climate change, collective action, global governance, catastrophic risk, existential risk