A research team led by Professor Mu Cuicui from the School of Earth and Environmental Sciences at Lanzhou University has made significant progress in understanding riverine CO₂ emissions in the permafrost regions of the Northern Hemisphere. Their findings were published online inNature Communicationson April 16, 2025, under the title“Recent intensified riverine CO₂ emission across the Northern Hemisphere permafrost region.”
Link to article:https://www.nature.com/articles/s41467-025-58716-3
Professor Mu Cuicui is the first and corresponding author of the paper. The research team includes master's student Li Kun, PhD candidates Wei Yuguo and Mu Mei, among others. The study was conducted with support from institutions such as Beijing Normal University, Sichuan University, East China Normal University, and Umeå University. It was funded by the National Key R&D Program of China (2024YFF0810900) and the National Natural Science Foundation of China (Grant No. 42371132).
Riverine CO₂ emissions account for approximately 85% of total CO₂ emissions from inland waters globally, making them a critical component of the global carbon cycle. The Northern Hemisphere permafrost region spans 21 million square kilometers and holds about 50% of the global soil carbon stock, representing the largest terrestrial carbon reservoir.As global warming accelerates permafrost degradation, ground temperatures rise and underground ice melts. This accelerates lateral carbon transport from soils to aquatic ecosystems, where part of the carbon is mineralized and released into the atmosphere as greenhouse gases. This intensifies the permafrost carbon–climate feedback. Although terrestrial ecosystems in these regions currently act as carbon sinks, CO₂ emissions from inland waters significantly offset this function. However, existing terrestrial carbon budget models often overlook riverine carbon processes, and there has been a lack of precise quantification of the spatial-temporal dynamics, mechanisms, and impacts of riverine CO₂ emissions in permafrost regions.
Figure 1: Environmental drivers of riverine CO₂ emissions in the Northern Hemisphere permafrost region
Using field observations from northeastern Qinghai-Tibet Plateau and extensive literature data, the research focused on the partial pressure of CO₂ in 5,685 rivers across the Northern Hemisphere permafrost zone. By integrating climate, permafrost, topography, soil, vegetation, and anthropogenic factors into machine learning models, the study expanded annual riverine CO₂ emission estimates from 2000 to 2020 across Arctic and Tibetan Plateau regions.
Total riverine CO₂ emissions were found to be 200 ± 15 Tg C per year, with an annual increase rate of 0.42 ± 0.16 Tg. Based on CMIP6 NEP model data, the study quantified that riverine CO₂ emissions offset 28.1 ± 2.1% of the land carbon sink in these regions, with clear variations among different permafrost zones. Further analysis identified that changes in precipitation and permafrost degradation were the dominant drivers of increased riverine CO₂ emissions in the Arctic and Qinghai-Tibet Plateau, explaining 57.3% and 55.0% of the variability, respectively.
Figure 2: Riverine CO₂ emissions and terrestrial carbon uptake across the Northern Hemisphere permafrost region from 2000 to 2020
Figure 3: Environmental driving factors of riverine CO₂ emission changes in the Northern Hemisphere permafrost region
This study reveals the distinct patterns of riverine CO₂ emissions between the Arctic and the Qinghai-Tibet Plateau, showing that they are predominantly controlled by precipitation and permafrost degradation, respectively. It also demonstrates how global warming is accelerating carbon release from rivers, thereby intensifying the positive permafrost carbon–climate feedback. These findings provide important scientific evidence for understanding the changing dynamics of riverine carbon emissions and their role in global carbon–climate feedback under climate warming.
Mu, C. C.*, Li, K., Liu, S. D., Wei, Y. G., Mu, M., Shang, X. X., Liu, F. M., Zhang, C. L., Liu, H. B., Gao, T. G., Song, C. L., Zhang, L. W., Karlsson, J. 2025.Recent intensified riverine CO₂ emission across the Northern Hemisphere permafrost region.Nature Communications, 16(1): 3616.
