Linked from
The 17 pages that link to Permafrost carbon cycle, each with the reason it gives.
Arctic tundraRelated: Tundra thaw can release carbon previously stored in frozen organic matter.
TaigaRelated: Thaw can expose stored organic matter to decomposition and release greenhouse gases.
Lyakhovsky IslandsRelated: Thawing island soils can release stored carbon.
New SiberiaRelated: Thawing permafrost in Arctic landscapes may alter greenhouse-gas emissions.