A new study of 50 rivers on the Qinghai-Tibet Plateau reveals that thawing permafrost does more than release ancient carbon. As frozen ground retreats, it exposes fresh rock that pulls carbon dioxide out of river water through natural weathering reactions. The research found that across the region, rock weathering offsets roughly a third of the carbon dioxide that rivers emit. In areas where permafrost is patchy, weathering can even turn rivers into a net carbon sink. This finding challenges climate models that treat thawing permafrost as a one-way carbon source. The study, published in Nature, shows that biological and geological carbon cycles are tightly linked. However, the researchers caution that weathering is not a climate cure. Some minerals release carbon dioxide as they break down, and some captured carbon may eventually return to the air in the ocean. Future carbon models will need to account for both soil and rock dynamics to accurately predict the net effect of a warming north.
