The cryosphere beyond a planetary safe operating space

The cryosphere plays a vital role in regulating planetary dynamics and habitability, yet it remains unclear whether its essential functions remain within a safe operating space (SOS) amid Anthropocene change. Here, we propose a cryosphere SOS and systematically evaluate its contributions to Earth system resilience using the planetary boundaries framework. Multiple lines of evidence indicate an accelerating and partly irreversible loss of cryospheric integrity, driven by amplifying feedbacks. Key cryospheric control variables either have left or are committed to departing from Holocene-like conditions. We conclude that the cryosphere has breached its SOS and is on a trajectory that locks in long-term risks for human societies and ecosystems. Safeguarding planetary resilience therefore requires explicit consideration of cryosphere change and its interactions across the Earth system.