Heatwaves and wildfires are contributing to the tipping point risks in the world's vast permafrost regions, which contain 1,500 gigatons of carbon. This amount is three times more than all the living vegetation on Earth.
Professor Gustaf Hugelius from the Bolin Centre of Climate Research at Stockholm University highlights this as a major concern. As the climate warms, permafrost thaws, exposing ancient plant remains to microbes that release carbon dioxide and methane, creating a self-reinforcing warming process.
Once permafrost thaws and its ice melts, the landscape can change into new forms called thermokarsts, such as lakes or wetlands. These altered systems will continue to emit carbon for decades or centuries, as the changes are irreversible on a human timescale.
While a sudden global permafrost tipping point is not expected unless global heating reaches 6C, local tipping points are already occurring. By the end of the century, permafrost is projected to become a significant emitter of greenhouse gases. If the world warms by 1.8C to 3.6C, 200 to 300 gigatons of CO2 equivalents could be released.