Soil in the far Northern permafrost can be frozen several hundred meters deep. Permafrost soil has a constant year-round temperature of 0 degrees or lower and forms a solid foundation for building upon. Some permafrost caves were traditionally used as storage space for food during Summer. The arctic seabed in Siberia houses a large deposit of CO2 in the form of compacted Gas Hydrates. Increasingly subjected to warming, Siberia’s shallow shelf areas are melting, giving up greater amounts of methane than previously recorded, and softening the previously stable ground above.