Arctic Permafrost Thaw Accelerating Carbon Release Permafrost across the Arctic contains twice as much carbon as the entire atmosphere—approximately 1,700 gigatons. Warming temperatures have accelerated thaw rates: the active layer (seasonal thaw zone) has deepened by 30-40cm in some regions since the 1990s, releasing methane and CO2 that amplify warming in a self-reinforcing cycle. This matters because permafrost degradation represents a climate tipping point outside human control—once initiated, it continues independent of emissions reductions, potentially adding 0.13-0.27°C of warming by 2100 beyond current mitigation scenarios.