How does thawing permafrost expose dead organic matter to microbial decomposition?

Permafrost acts as a long-term storage repository for vast amounts of dead organic matter, which remains preserved for thousands of years primarily because the ground stays frozen.1

When permafrost thaws due to rising temperatures, this organic material—which was previously locked away in the ice—becomes accessible to microorganisms. Once exposed, these microbes begin the process of decomposition, breaking down the organic matter. This biological activity releases stored carbon into the atmosphere in the form of carbon dioxide (under aerobic conditions) or methane (under anaerobic conditions).1

Because methane has a significantly higher greenhouse warming potential than carbon dioxide, this microbial decomposition creates a positive feedback loop: the release of these gases contributes to further global warming, which in turn accelerates the rate of permafrost thawing and exposes even more organic matter to further decay.21