In streams on the Tibetan Plateau, new measurements indicate that mineral weathering may offset some of the river emissions.

The thaw of the permafrost It is often described as a climatic fuse: the frozen ground warms up, the organic matter that has remained trapped for millennia becomes available again, microorganisms and watercourses transform it into CO2 e methane, and the atmosphere receives new greenhouse gases. A research published in "Natures” il June 17, 2026 But it introduces a less linear element. Degrading frozen soil not only releases ancient carbon: it can also expose minerals capable of removing carbon dioxide from the atmosphere throughchemical alteration of rocks.

The study, relaunched by Federal Polytechnic of Lausanne, does not downplay the climate risk associated with thawing. On the contrary, it shows how incomplete models are that treat permafrost solely as a source of emissions. The international group, with researchers from Germany, China, Sweden, Switzerland, UK e United States, he analyzed 50 rivers of the Qinghai Plateau-Tibet, in the sources of some of the major Asian river basins. The studied area covers approximately 780.000 square kilometers and extends between 1.650 and 4.820 meters of altitude.

The key finding is that carbon fluxes generated by rock weathering can offset a significant portion of riverine CO2 emissions. According to the results, the offset ranges from approximately 15 percent in areas with continuous permafrost over 100 percent where coverage is sporadic or isolated. On a regional scale, the scientific article indicates a compensation of approximately 35 percent of river emissions, while the analysis along the degradation gradient highlights an overall median value of 78 percent.

A geochemical mechanism that enters the climate budget

To understand the result, we need to distinguish between two components of the carbon cycle. The first is biological: thawed organic matter is degraded and can produce CO2 or CH4. The second is geological: water interacts with minerals released by the thaw, changing their chemical composition and, under certain conditions, consuming CO2, forming bicarbonates and other dissolved compounds that are transported by rivers.

This second phenomenon, known as rock weathering, is not new to Earth sciences. However, it is less considered in permafrost studies, where attention often focuses on organic deposits and direct emissions. The work coordinated by Liwei Zhang, biogeochemist of the East China Normal University and Aaron Bufe, professor of sedimentology at the Ludwig-Maximilians-University Munich, approaches the problem as a balance between release and seizure.

“We were surprised by the scale of the effect,”

says Tom Battin, laboratory director River Ecosystems Laboratory of EPFL and co-author of the study.

The surprise lies not only in the magnitude of the phenomenon, but also in the interaction between organic and inorganic carbon. Isotopic and chemical measurements indicate that the Plateau's rivers receive carbon from both frozen soils and rocks. In other words, the river system does not act as a simple pipeline transferring CO2 to the atmosphere: it is a reactive environment, in which water, minerals, organic matter, and microbial processes continuously modify the chemical form of carbon.

The Tibetan Plateau as a natural observatory of change

Il Qinghai Plateau-Tibet It is the largest continuous cryosphere outside the Arctic and Antarctica. For this reason, it represents a natural observatory for understanding what happens when permanently frozen ground fragments, recedes, or disappears. In some sampled areas, permafrost is still continuous; in others, it is discontinuous, sporadic, or already absent. This distribution has allowed researchers to use space as an indicator of transformations that, over time, occur on scales of decades or centuries.

The analyses combined CO2 emission measurements, dissolved organic and inorganic carbon concentrations, isotopic data, and geochemical modeling. Sampling covered the headwaters of large Asian river systems, including Yellow River, yangtze, Lancang, Nu, Yarlung Tsangpo e IndoThe territorial scale is important because it allows us to link the behavior of watercourses to the composition of the landscape, altitude, average temperature, and the presence of various minerals.

“In our study we carefully quantified how the ratio between CO2 sequestration and release changes as permafrost thaws,”

adds Tom Battin.

The methodological element is also relevant for the Research Climate. Global models must account for phenomena occurring at vastly different scales: from the chemical reaction between water and minerals to planetary atmospheric circulation. If certain processes are neglected, projections risk overestimating or underestimating specific components of the carbon budget. In this case, the message is not that the melt is less severe, but that its net effect depends on multiple simultaneous mechanisms.

Silicates and sulfides in the environment produce opposite climatic effects

Not all rocks react in the same way. The weathering of silicates, widespread in large areas of the Plateau, can contribute to the removal of CO2. The case of sulfur-containing minerals, such as pyrite, whose oxidation can produce sulfuric acid and instead promote the release of CO2, especially when it interacts with carbonate rocks. Local geology therefore becomes a decisive factor: the same physical dynamics, the thawing of the ground, can trigger chemical responses with different climatic characteristics.

The EPFL source highlights that the alteration process tends to become more significant as the permafrost degrades. In areas with continuous cover, the compensation of river emissions remains around 15 percent. Where frozen ground is sporadic, the altitude can exceed 100 percent, suggesting that in some basins the uptake associated with minerals may exceed the CO2 produced in rivers by the transformation of organic carbon.

“Across the entire region we studied, 35 percent of CO2 emissions from rivers are offset by carbon sequestration due to rock weathering,”

explains Liwei Zhang.

“What is interesting is that this relationship depends very much on the nature of the permafrost.”

These numbers should not be interpreted as a climate license. The relationship between emissions and sequestration in the Plateau rivers concerns a specific system, with precise geological and hydrological conditions. Its usefulness lies in demonstrating that the response of the biosphere and geosphere The relationship between climate change and global warming is less binary than it often appears in public debate. The implications are of interest to research centers, organizations that develop carbon inventories, and institutions responsible for assessing risks in high-altitude areas.

More accurate climate models, not a natural solution

A crucial issue concerns the transferability of the results. Permafrost covers approximately a quarter of the earth's land mass, especially in the Arctic, but also in Antarctica and mountainous regions such as the Alps. However, mineralogical composition, hydrology, temperature, vegetation cover, and basin morphology vary from one area to another. The case Tibetan It can therefore improve our understanding of the processes, but it is not enough to automatically generalize the balance to all cold regions of the planet.

For climate policies and for the sustainabilityThe trickiest point is to avoid a consolatory interpretation. Rock weathering can offset part of the emissions induced by melting in specific river systems, but it does not cancel out the anthropogenic increase in greenhouse gases. According to Aaron Bufe, the scale of the phenomenon remains too small compared to the emissions produced by human activities.

“Unfortunately the answer is no,”

says Aaron Bufe regarding the possibility that rock weathering offsets anthropogenic climate change.

Annual human-produced CO2 emissions are about 100 times greater than the amount sequestered by weathering. A slight increase in weathering rates with permafrost thaw won't alter this enormous difference. The most useful thing to do would be to drastically reduce emissions.

The industrial and institutional value of the study therefore lies in the quality of the information, not in the promise of natural compensation. Improving models means more reliable estimates of climate feedbacks, carbon stocks, and risks for mountain and Arctic regions. For energy companies, insurance companies, land-use planners, and public administrations, more precise data helps assess infrastructure, water resources, soil stability, and the vulnerability of exposed communities.

The research also suggests a direction for future studies: moving beyond a focus on biological processes and considering organic carbon, inorganic carbon, mineralogy, and hydrology together. Permafrost remains a sensitive indicator of global warming, but its actual impact depends on networks of reactions that span soil, rock, water, and the atmosphere. Understanding these connections doesn't reduce the urgency of mitigation; it strengthens the scientific basis on which to build it.

Here are three insights that might interest you:

Here's Why the Arctic Ocean Will Absorb Less CO2 Than Expected
Why are Alaska's rivers turning orange?
Permafrost in Yakutia: Innovative Strategies to Prevent Thawing