Climate change is leading to increased carbon uptake in upper layers of permafrost soils in the Tibetan Plateau, according to a study published online this week in Nature Geoscience. The study suggests that carbon sequestration in these upper layers may help to offset carbon released from deeper layers of permafrost that is now thawing.

Large amounts of carbon have been stored in frozen permafrost soils for thousands of years, including in the Tibetan Plateau, which has the largest extent of alpine permafrost in the world. Warming temperatures have been shown to thaw permafrost and release some of this carbon to the atmosphere. However, the effects of warming on the balance of carbon uptake and loss in permafrost regions in recent decades remain unclear.

Yuanhue Yang and colleagues measured soil carbon stocks in permafrost across the Tibetan Plateau in the early 2000s and again in the early 2010s. They find that the amount of carbon stored in soil layers just below the surface increased over time, during a period when the plateau experienced warming. They suggest that the increase in carbon stocks is probably the result of climate-change-enhanced vegetation growth in the region.

This accumulation of carbon in Tibetan Plateau permafrost soils represents a negative feedback to rising atmospheric CO2 concentrations, which could help slow the pace of climate change.