Why thawing permafrost matters
Permafrost is ground that remains frozen for two or more consecutive years. It is composed of rock, soil, sediments, and varying amounts of ice that bind the elements together. Some permafrost has been frozen for tens or hundreds of thousands of years. Found under a layer of soil, permafrost can be from three feet to 4,900 feet thick. It stores the carbon-based remains of plants and animals that froze before they could decompose. Scientists estimate that the world’s permafrost holds 1,500 billion tons of carbon, almost double the amount of carbon that is currently in the atmosphere. Unfortunately, when permafrost warms and thaws, it releases carbon dioxide and methane into the atmosphere. As the global thermostat rises, permafrost, rather than storing carbon, could become a significant source of planet-heating emissions.