In subarctic Iceland, grassland plants shuttle large amounts of carbon underground through their root systems, and most of that carbon ends up stored in the soil. Because livestock graze on these plants, a common assumption has been that grazing reduces the amount of carbon captured and retained. However, new research indicates that, at least in this region, grazing may actually enhance soil carbon storage rather than diminish it.
The study's findings run counter to the prevailing view that herbivores generally deplete carbon reserves in grassland soils. While the exact mechanisms are still being explored, the results suggest that moderate grazing can promote root turnover or alter plant communities in ways that increase carbon input to the soil. This nuance matters for climate policy, since promoting soil carbon storage is seen as a way to help offset atmospheric carbon dioxide.
If grazing can be managed to boost carbon storage, it could change how subarctic grasslands are valued—not just for livestock production but also as a natural climate solution. The researchers emphasize that their results are specific to Iceland's subarctic grasslands, and caution against assuming the same effect applies elsewhere. Further work is needed to understand how grazing intensity, timing, and local conditions influence the balance between plant growth and soil carbon accumulation.