Northern-hemisphere permafrost holds ~1700 Gt carbon (twice atmospheric); active-layer deepening releases CO2 and CH4; Stefan equation governs phase-change-front; abrupt thermokarst accelerates thaw.
Northern-hemisphere permafrost holds ~1700 Gt carbon (twice atmospheric); active-layer deepening releases CO2 and CH4; Stefan equation governs phase-change-front; abrupt thermokarst accelerates thaw.