Permafrost holds ~1,700 Gt of organic carbon — twice the atmosphere's CO₂. Warming releases it as CO₂ and CH₄, amplifying climate change.
As ice-rich permafrost thaws, land collapses into ponds and depressions. Ground can sink meters in decades, reshaping Arctic landscapes.
Permafrost → CO₂/CH₄ → warming → more permafrost thaw. A self-reinforcing loop that could become unstoppable past a tipping point.