A new study led by the Joint Research Centre (JRC) and published in Nature Communications highlights that the soil organic carbon pool is at high risk across 43 to 83 million hectares of agricultural land in the EU and UK. This figure represents approximately 23% to 44% of all agricultural land in the region, with the most vulnerable areas located in cool and humid climates. Conversely, between 26 and 50 million hectares show no immediate risk and offer strong potential for additional carbon storage, being far from saturation and capable of protecting new carbon inputs effectively.
The study stresses that most EU agricultural soils urgently require enhanced protective measures. Recommended interventions include cover cropping, improved crop rotations, reduced tillage, the use of deep-rooted crops, increasing organic amendments, and the adoption of agroforestry systems. Implementing these strategies could optimize the storage of soil organic carbon in a more stable form, contributing significantly to both climate change mitigation and soil health.
The importance of soil organic carbon cannot be overstated. Agricultural soils in the EU alone store over ten times the carbon equivalent of the region’s annual greenhouse gas emissions. Besides its role in climate regulation, soil organic carbon supports key soil functions, such as improving soil structure, boosting water retention, enhancing nutrient availability, and increasing resilience to climatic and land use disturbances. However, ongoing climate changes have intensified soil degradation. Between 2009 and 2018, European agricultural soils experienced a relative loss of 0.75% of their total organic carbon content, underscoring the urgent need for corrective action.
Crucially, the study highlights that not all soil carbon is equally protected. Some carbon pools are tightly bound to fine mineral particles, offering stability up to a saturation point. Beyond this limit, soils become more susceptible to carbon loss. Traditional models assumed a universal saturation capacity, but new findings suggest that “effective saturation capacity” varies across different soil and climate conditions. This led researchers to develop a novel risk index that combines soil carbon changes (hazard) with the degree of saturation (vulnerability). This index identifies both high-risk areas for future carbon losses and regions that could effectively accrue more carbon.
At the policy level, the European Union has incorporated measures to safeguard and enhance soil organic carbon within its Common Agricultural Policy (CAP). Farmers are supported through mandatory and voluntary actions outlined in the CAP Strategic Plans, promoting sustainable soil management practices. Additionally, the EU has introduced a Carbon Removal and Carbon Farming certification framework, creating new business opportunities in the voluntary carbon market. This framework rewards farming practices that actively increase soil carbon while maintaining biodiversity and preventing land degradation.
The study’s development of a risk index marks a significant advancement in targeted carbon management. It equips policymakers and land managers with precise tools to prioritize interventions, aiming to both preserve existing soil organic carbon and foster conditions for additional sequestration. By doing so, it strengthens efforts to mitigate climate change impacts and promotes more resilient, productive agricultural landscapes across Europe and the UK.
https://phys.org/news/2025-04-soil-carbon-large-european-agricultural.html