A recent study published in Nature Geoscience has shed light on the sensitivity of soil carbon dioxide (CO2) emissions to climate warming in permafrost-collapsed areas compared to non-collapsed areas. The research, based on field warming experiments and laboratory soil incubation, provides important insights into the permafrost carbon-climate feedback in the face of future climate change.
With rising global temperatures, permafrost in high-latitude and high-altitude regions has been thawing at an alarming rate. This rapid permafrost thaw, also known as thermokarst, affects around 20% of the northern permafrost region, yet stores approximately half of all below-ground organic carbon. Thermokarst formation can lead to significant changes in land surface morphology, impacting both biotic and abiotic properties of the soil and potentially altering ecosystem carbon cycling.
A collaborative research team led by Prof. Yang Yuanhe from the Institute of Botany of the Chinese Academy of Sciences conducted a study to investigate how thermokarst formation influences the response of soil CO2 fluxes to climate warming. In a controlled warming experiment conducted in thermokarst and non-thermokarst areas, the researchers discovered that the increase in soil CO2 release due to warming was significantly higher in thermokarst features compared to non-thermokarst landforms. The study analyzed various factors contributing to this difference, including soil physicochemical properties, microbial genes related to organic carbon decomposition, and temperature sensitivity of CO2 release.
Implications of the Study
The findings of this study suggest that warming-induced soil CO2 loss is more pronounced in areas affected by thermokarst formation. The researchers estimate that extrapolating the results to all upland thermokarst regions in the Northern Hemisphere could lead to an additional 0.4 Pg C year-1 of soil carbon release. This represents a significant portion of the projected permafrost soil carbon losses by the end of the 21st century.
The study highlights the critical impact of climate warming on soil CO2 emissions in permafrost regions, particularly in areas experiencing thermokarst formation. Understanding the dynamics of soil carbon cycling in response to warming is essential for accurately predicting the future trajectory of permafrost carbon-climate feedback. Further research in this field is needed to address the complex interactions between climate change, permafrost thaw, and ecosystem carbon dynamics.