Frozen Ground & Permafrost
by NSIDC
When water turns into ice in soil, it becomes frozen ground. Permafrost is soil, sand, sediment, or rock that remains at or below 0 °C (32 °F) for at least two years. 0ne-fourth of the land in the Northern Hemisphere has an underground layer that stays frozen all year. If it continues to stay frozen for at least two years, it becomes permafrost.
In many areas, permafrost has been frozen for thousands of years, storing nearly one-third of Earth’s soil carbon. As global temperatures rise, thawed soils release the carbon that then turns into heat-trapping greenhouse gases, like carbon dioxide or methane. Scientists conduct research, using various data sources, to better understand the impacts of a future with less frozen ground.
