Permafrost Thaw Dynamics: Active-Layer & Carbon Release (2D)

This 2D companion trades the 3D version's orbiting camera for a readable ground cross-section: a Stefan-style freeze/thaw front sinks from the surface each simulated summer and climbs back each winter, and once the air-temperature anomaly is high enough the front stops fully retreating — the permafrost table itself starts to ratchet downward, opening an unfrozen talik gap. Ground-ice content controls how much of that newly-thawed ground settles as visible thermokarst subsidence (and, past a threshold, a meltwater pond), while soil organic-carbon content drives a live carbon-flux readout as previously-frozen ground is exposed to decomposition for the first time — the same active-layer deepening, thermokarst and old-carbon release mechanics described in the source article, just made directly watchable instead of implied by a decorative scene.