Removing sheep and other livestock entirely from upland grasslands—a strategy often promoted as a way to boost carbon storage and tackle climate change—may actually reduce the most stable forms of soil carbon, according to new research. The study suggests that while removing livestock from upland grasslands can increase fast-cycling carbon stored in plants and dead vegetation, it can also lead to losses of a more stable form of soil carbon. This long-lived carbon, known as mineral-associated organic carbon (MAOC), is bound to soil minerals and can persist for decades to centuries, making it critical for long-term climate mitigation.
Grasslands store around one-third of the world’s terrestrial carbon, with the vast majority being found in soils. As governments pursue net-zero targets, removing livestock from historically grazed grasslands has increasingly been proposed as a scalable climate solution.
Traditionally, scientists and land managers have relied on “total carbon stocks” to assess carbon removal projects. However, the findings show that focusing solely on the total amount of carbon stored, rather than how securely it is stored, may be misleading.