Arctic permafrost holds 63 billion tons of carbon, scientists warn of climate risks

Scientists have found that Arctic river deltas contain roughly 63.4 billion tons of carbon locked in frozen permafrost. This is about 5% of all permafrost carbon stored in just 1% of the permafrost area. The carbon comes from ancient plant material preserved by cold conditions over thousands of years. As temperatures rise, the permafrost thaws and microbes start breaking down that organic matter. This releases carbon dioxide and methane, two greenhouse gases that accelerate global warming. The study also found 4.2 billion tons of nitrogen stored alongside the carbon, which could affect how ecosystems respond to thawing. The concern is not an instant release but a gradual chain reaction. Warmer conditions lead to more thawing, which leads to more emissions. Arctic river deltas are complex environments where rivers, oceans, ice, and frozen soils interact. Researchers analyzed over 1,600 soil samples from 17 deltas including the Lena River in Siberia and the Mackenzie River in Canada to reach these numbers.