Overview
- A paper led by Bo Su published in Science on Thursday, November 12 reports that multiple frozen systems have left their defined safe operating space, marking an accelerating and partly irreversible loss of cryosphere integrity.
- The study finds Arctic and Antarctic sea ice, snow cover, and permafrost area have moved beyond their safety thresholds while global land ice is very close to breaching its limit.
- The authors evaluated concrete control variables—land ice volume, sea ice area, snow cover area, and permafrost temperature—and show those measures have deteriorated or are committed to deteriorating past Holocene levels.
- The loss raises clear physical risks: the West Antarctic Ice Sheet holds enough ice for roughly three meters of sea-level rise, thawing permafrost could release large stores of CO2 and methane, and changes to ice can disrupt ocean circulation and regional water supplies.
- The paper calls for immediate cuts to greenhouse gases and black carbon, reduced local disturbance in cold regions, and targeted research on costly and uncertain local or engineered interventions while warning these actions do not replace rapid global emissions reductions.