BEIJING, April 24 (Xinhua) -- More than two-thirds of the permafrost in northeast China has changed stability over the past two decades, driving a fundamental shift in the region's vegetation, with grasslands shrinking, shrubs spreading and broadleaf forests expanding at the expense of coniferous trees, according to a new study.
The finding offers a critical new lens for understanding how frozen ground responds to climate change, serving as a reminder for policymakers to fully consider this linkage when making policies on forest tending, grassland restoration and carbon sink management, according to a report in Science and Technology Daily on Thursday.
Permafrost, the ground that remains frozen for at least two consecutive years, functions like an "underground glacier" across vast areas of the planet's cold climates.
However, new research from Northeast Forestry University shows that in the "active permafrost zone," which accounts for about 18.8 percent of the study area, nearly 67.5 percent of permafrost experienced at least one shift in stability between 2000 and 2024. In some areas, it fluctuated between "unstable" and "semi-stable" states as many as four times over the study period.
"Permafrost change explains vegetation succession better than previously understood," said Shan Wei, a professor at Northeast Forestry University and corresponding author of the study. "This requires a coupled underground-aboveground perspective in cold-region ecosystem management."
The study, published in Communications Biology, a journal under the Nature portfolio, found a clear link that the more frequently permafrost stability changes, the stronger the ecosystem disruption. Broadleaf forests are expanding, which may temporarily increase carbon absorption. But as permafrost thaws, water tables can drop and ancient stored carbon can be released, making the region's carbon balance increasingly uncertain.
"Policies on forest tending, grassland restoration, and carbon sink management must fully consider this linkage," Shan added.
The research not only quantifies permafrost's rapid transformation in China's cold regions but also provides a scientific basis for building climate resilience into ecosystem management, a long-term challenge for achieving harmony between people and nature in the region, the report said. ■
