Where is permafrost found in the Arctic and subarctic regions?

Permafrost is widespread throughout the Arctic and subarctic regions, where it is estimated to underlie 24 percent of the land surface in the Northern Hemisphere. Its distribution is generally categorized into two zones based on lateral continuity:1

• Continuous Zone: Located in the far north, permafrost is nearly ubiquitous here, except beneath large bodies of water that do not freeze to the bottom.2
• Discontinuous Zone: Found further south, this area contains numerous permafrost-free patches that increase in frequency toward the southern boundary, where only rare, isolated pockets remain.2

Geographically, permafrost covers approximately 85 percent of Alaska and 55 percent of both Russia and Canada. The southern limit of continuous permafrost often aligns with the northern forest belt, correlating with mean annual air temperatures of approximately –7 °C (20 °F). Additionally, unique subsea permafrost exists beneath the Arctic Ocean on the northern continental shelves of North America and Eurasia.23