A new study shows that thawing permafrost can accelerate rock weathering, a process that removes carbon dioxide from the atmosphere and offsets emissions from rivers in some regions.
Researchers from Umeå University in Sweden and East China Normal University in China examined 50 rivers on the Qinghai-Tibet Plateau. They found that as permafrost thaws, exposed minerals increase chemical weathering, which consumes atmospheric CO2.
The team reported that rock weathering offsets about 35 percent of river CO2 emissions on average across the study area. In areas with patchy permafrost, the uptake sometimes exceeded river emissions entirely.
"We found that river CO2 emissions decline while carbon uptake through rock weathering increases as permafrost cover decreases," said Liwei Zhang of East China Normal University. Jan Karlsson of Umeå University added that biological and geological carbon cycles must both be considered to assess the net climate impact.
The findings, published in Nature, indicate that geological processes can rival biological carbon release in thawing landscapes.