Common Property and the Conservation of Natural Resources

Abstract

This report provides an overall estimate of the extent of perennially, seasonally, and intermittently frozen ground of the exposed land surface in the Northern Hemisphere. Permafrost regions occupy about 24.91  106 km2 , 25.6% (including glaciers and ice sheet) or 22.79  106 km2 , 23.9% (excluding glaciers and ice sheet) of the land surface in the Northern Hemisphere. Using the 0 and 5°C isotherms of mean monthly air temperature, the extent of seasonally and intermittently frozen ground, respectively, can roughly be estimated over the land areas. The long-term average maximum extent of seasonally frozen ground is about 48.12  106 km2 or 50.5% of the exposed lands in the Northern Hemisphere. Intermittently frozen ground accounts for additional 6.27  106 km2 or 6.6% of the exposed lands in the coldest month of the year.