Agriculture is a major contributor to climate change, but there is overwhelming evidence that best-practice soil stewardship has the potential to be a key solution for addressing climate change and its stressors. Increasing soil carbon sequestration mitigates climate change and enhances soil health: building healthy soils increases water infiltration and holding capacity; reducing damaging runoff during floods and enhancing yield resilience during droughts reduces impacts from extreme weather events while also supporting food security.

Natural climate solutions (or NCS) are proven ways of storing and reducing carbon emissions in the world’s forests, grasslands and wetlands; soil carbon stewardship represents an important piece of the NCS portfolio. Rangelands are key contributors to this solution, and California’s rangelands—which cover 40% of the state—are vital for achieving the state’s climate mitigation goals. Maintaining soil carbon is essential for climate adaptation as well, and California’s AB 1757 legislation elevates natural and working lands climate-smart stewardship as an important pathway in their mitigation and adaptation portfolio.

The CO2 Foundation is supporting work to build the knowledge base and tools around land management strategies that can effectively sequester carbon, mitigate greenhouse gas emissions, and help rangelands maintain productivity while adapting to more extreme weather events throughout California. Pairing biogeochemical modeling with an unprecedented statewide study of rangeland stewardship stands to significantly improve understanding and prediction of how land management practices influence carbon sequestration over space and through time.

Point Blue Conservation Science will first analyze plant and soil carbon data from a California-wide study that aims to identify how riparian restoration, silvopasture, and perennial grass planting influence carbon sequestration and soil organic matter dynamics over time. Samples from 36 paired restored and unrestored sites spanning 15 counties and a 30+ year timeframe have already been collected by the project team and await data analysis and dissemination. Secondly, the team will use empirical data from the statewide study to evaluate and improve performance of the DayCent biogeochemical model. This model explores the long-term viability of net carbon sequestration and the effects of climate change on carbon sequestration and greenhouse gas dynamics in these restored systems.

Outcomes of this work will include a publicly available report documenting the carbon sequestration and greenhouse gas mitigation potential of rangeland stewardship across the state through the year 2100 under future climate scenarios. The report will also evaluate the accuracy of predictions put forth by COMET-Planner, a decision-support tool that is based on DayCent, for riparian restoration, perennial grass planting, and silvopasture in California. Findings will be used to adjust parameters in the model and revise regionally-specific emissions reduction coefficients.

This work is central to Point Blue’s strategy on agricultural lands and the knowledge gained will be used by dozens of staff who work directly with farmers and ranchers. This project will not only help to quantify the potential of different management practices for enhancing carbon stocks and mitigating greenhouse gas emissions but also inform decision-making for land managers and policymakers who rely heavily on COMET-Planner. USDA, the California Department of Food and Agriculture (CDFA) Healthy Soils program, Zero Foodprint’s Restore California, county-level climate action plans, and Carbon Farm Plans may all utilize COMET-Planner to prioritize projects and estimate impact. However, uncertainties and knowledge gaps persist, and the tool’s estimates are currently questionable for certain regions in California.

Engaging with end users throughout any project is key to adoption of results; the Point Blue project team will engage with end users through 1:1 or small group meetings, larger public forums, and electronic communications. In every appropriate interaction, project communications will be embedded to share findings and learn from others about how this work can help meet their emerging needs. By strengthening our understanding of the relationships between rangeland management, carbon sequestration, and ecosystem resilience under changing climatic conditions, our project will help to advance nature-based solutions to climate change mitigation and adaptation in an unprecedented way for rangelands across California and beyond.