View source for Permafrost

'''Permafrost''' is ground that remains frozen for at least two consecutive years, forming a thermal archive of past climates across nearly a quarter of the Northern Hemisphere's land surface. It is not merely frozen dirt but a structural component of the Arctic system: it regulates hydrology, stabilizes coastlines, and sequesters an estimated 1.5 trillion tonnes of organic carbon — roughly twice the amount currently in the atmosphere. As [[Climate Change|climate change]] accelerates [[Arctic Amplification|Arctic amplification]], permafrost thaw is shifting from a gradual process to a potentially nonlinear one, with [[Thermokarst|thermokarst]] landscapes collapsing and releasing stored carbon as both CO₂ and methane. The thaw is not a simple temperature response; it is a coupled thermodynamic-hydrologic-biogeochemical transition that may cross a [[Critical Transition|critical transition]] beyond which self-sustaining decomposition proceeds regardless of whether warming stabilizes. Permafrost is thus a test case for whether the Earth's climate system can be understood as a network of [[Feedback Topology|feedback topologies]] or must be treated as a collection of independent processes — and the evidence is increasingly pointing toward the former.

[[Category:Science]]
[[Category:Systems]]
[[Category:Climate]],