To limit risks for human societies and secure critical Earth system functions they propose a new framework of planetary commons to guide governance of the planet. “Stability and wealth of nations and our civilisation depends on the stability of critical Earth system functions that operate beyond national borders. At the same time, human activities push harder and harder on the planetary boundaries of these pivotal systems. From the Amazon rainforest to the Greenland ice masses, there are rising risks of triggering irreversible and unmanageable shifts in Earth system functioning. Legal, political and Earth system scientists make their case by building on the well-known idea of the global commons.