Thawing permafrost triggers rock weathering that offsets river CO2 emissions, study finds

A new study published in Nature reveals that thawing permafrost can accelerate rock weathering, a natural process that pulls CO2 from the atmosphere. Researchers studied 50 rivers on the Qinghai-Tibet Plateau and found that weathering-driven carbon uptake offset about 35% of river CO2 emissions on average. In areas with patchy permafrost, the offset sometimes exceeded 100%, meaning more CO2 was absorbed than released. The findings add complexity to how scientists model the carbon cycle in warming regions. While thawing permafrost is known to release ancient organic carbon as greenhouse gases, this study shows that geological processes can partially counteract those emissions. The authors caution that rock weathering is not a permanent climate fix, but it is a missing piece in current climate models. For carbon markets and climate policy, this research underscores the importance of accounting for natural carbon sinks beyond forests and oceans. It also highlights the need for more granular data on how permafrost regions behave as both sources and sinks of CO2 as the planet warms.