Permafrost to stop absorbing carbon and start emitting CO₂ by 2050

Deep permafrost in the Northern Hemisphere is on track to become a net emitter of carbon dioxide by mid-century, potentially accelerating climate change far beyond current projections. A new study, published in Science Advances, indicates that existing climate models have underestimated the rate at which this deep permafrost will thaw. Researchers from the Climate and Environmental Sciences Laboratory in France, collaborating with institutions in China and Sweden, analyzed the thawing process, focusing on Yedoma deposits and peatlands. These vast, deep carbon reserves, vulnerable to rising global temperatures, have not been fully accounted for in climate projections like CMIP6, which inform the Intergovernmental Panel on Climate Change (IPCC) reports. Current models primarily consider the upper layers of permafrost, which freeze and thaw seasonally. However, the new research highlights that as temperatures climb, the active layer of soil will deepen, exposing deeper, ancient carbon stores to higher temperatures. This process could release significant amounts of stored carbon, exacerbating the warming trend. The study warns that the Arctic's impact on global climate change could be far more immediate and severe than previously anticipated, particularly if greenhouse gas emissions remain high.