Further statistics on the distribution of permafrost and ground ice in the Northern Hemisphere1

Abstract The authors, based on the International Permafrost Association (IPA) Circumarctic Map of Permafrost and Ground Ice Conditions, determine the area occupied by the permafrost region (up to 22.79 × 106 km2, or 23.9% of the exposed land area of the Northern Hemisphere). They argue, however, that permafrost may not be present everywhere within this permafrost region. They present estimates that indicate that the actual area underlain by permafrost is smaller (ranging approximately from 12.21 to 16.98 × 106 km2, or from 12.8% to 17.8% of the exposed land area). They also estimate the volume of ground ice, as varying approximately from 10.80 to 35.46 × 103 km3 (about 2.7 to 8.8 cm sea‐level equivalent).