Chesapeake Bay Restoration Efforts in Virginia Provide Climate Change Benefits

Study Shows Efforts to Improve Water Quality Also Counter Climate Warming

Annapolis, Md – Today, Chesapeake Conservancy’s Conservation Innovation Center (CIC) released a new report, Climate Benefits of Chesapeake Bay Restoration in Virginia. The report examines how efforts to improve water quality in Virginia’s portion of the Chesapeake Bay watershed have also provided a secondary benefit of helping to remove carbon from the atmosphere.

“We wanted to understand better how efforts implemented under the Chesapeake Bay Watershed Agreement to improve water quality in Virginia could also generate significant climate mitigation benefits by removing carbon from the atmosphere and storing it in vegetation or soil,” said Chesapeake Conservancy Vice President of Technology Susan Minnemeyer. “The results showed meaningful co-benefits for climate change leaders to consider when scaling conservation and restoration practices throughout the entire Chesapeake Bay watershed. This is proof that restoration projects that aim to improve water quality are also powerful tools to fight climate change.”

“This estimate corroborates findings in a Virginia Department of Environmental Quality evaluation conducted in 2020 which also included analysis of Virginia’s Phase III Watershed Implementation Plan (WIP), also known as the WIP,” said Chesapeake Bay Program Manager James Martin. “Our estimates suggest that the water quality actions in Virginia’s WIP, when fully implemented, could produce more than two million tons of climate mitigation co-benefits while also improving soil health and the resilience of Virginia farms to climate change.”

“Based on our analysis for 2019, we estimate that 459,639 tons (416,987 metric tons) of carbon dioxide (CO₂) equivalent per year are removed from the atmosphere by agricultural conservation practices,” said Chesapeake Conservancy Senior GIS Analyst Emily Wiggans. “This amount equates to the annual carbon sequestration of 510,000 acres of average U.S. forests or approximately 0.4% of Virginia’s energy-related CO₂ emissions.”

Results of this study indicate that a large opportunity exists for accelerating climate action within the Chesapeake Bay watershed. The 460,000 tons of annual carbon removal benefits generated by ongoing restoration activities within the agricultural sector in Virginia represent a small portion of the potential mitigation that could be generated with targeted planning and additional investment in the practices that promise the greatest co-benefits for water quality improvement and climate mitigation. The Chesapeake Bay Program provides a robust management framework and technical expertise for scaling land-based climate solutions.

Results

The analysis results showed carbon sequestration from Virginia’s 2019 Best Management Practices (BMPs) totaled 459,639 tons (416,987 metric tons) of CO₂ equivalent for one year for practices on 1,699,050 acres of agricultural land. Practices that included the establishment of trees and shrubs removed 188,833 tons of carbon dioxide equivalent on 41,646 acres of farmland, with the greatest amount of carbon sequestered in silvopasture, a conservation practice that increases tree canopy coverage to at least 10%. Silvopasture provides shade for livestock, increases climate resiliency, reduces erosion, improves water quality, enhances wildlife habitat, and improves soil quality. BMPs that included the establishment of perennial woody vegetation such as trees and shrubs generated far greater climate mitigation benefits per acre compared to other BMPs such as reduced tillage, cover cropping and fertilizer management. However, within Virginia’s three million acres of cropland, the land area available for tree and shrub establishment is much smaller than the area occupied by crops. Increasing forest and tree canopy cover provides the greatest carbon removal opportunity per acre, while the number of acres available for other agricultural BMPs such as cover crops or reduced tillage is far larger. The total carbon sequestration for cropland conservation practices and herbaceous buffers was 270,807 tons on 1,657,404 acres of land.

Both types of practices enhance soil carbon, while only practices involving the establishment of woody vegetation like trees and shrubs sequester large amounts of carbon above-ground. The science underpinning forest carbon sequestration is also more established than that for soil carbon sequestration generated by regenerative agricultural practices. The sheer size in acres of croplands have generated a great amount of interest in the climate benefits of climate-smart agriculture. Research is ongoing to develop greater certainty for soil carbon accounting and to establish protocols for soil carbon enhancement practices to increase confidence in soil carbon enhancement.

Methodology

The methods set out to determine climate benefits of land-based agricultural BMPs towards Chesapeake Bay restoration in Virginia used the COMET-Planner tool developed by Colorado State University and the U.S. Department of Agriculture’s (USDA) Natural Resources Conservation Service (NRCS). The COMET-Planner tool estimates greenhouse gas reduction and carbon sequestration benefits based on USDA NRCS Practice Standards in the state and county where the practice is implemented. Extensive greenhouse gas emission reductions result from sectors that were beyond the scope of this study. These include conservation practices for animal agriculture, such as improved livestock and manure management. Chesapeake Bay Program BMPs that increased urban and suburban tree planting, green infrastructure for stormwater management and wetland restoration were not included.

To estimate carbon removal benefits for Virginia BMPs, all recorded BMPs for Virginia within the Chesapeake Bay watershed for the year 2019 were identified. Next, the corresponding conservation practice as defined by the USDA Natural Resources Conservation Service were identified, and the COMET-Planner tool was used to estimate total carbon dioxide equivalent (CO₂e) removed from the atmosphere for the area of that practice per county. Carbon removal benefits were estimated only for agricultural BMPs that could be matched to an NRCS conservation practice.

To read the study in its entirety, visit https://www.chesapeakeconservancy.org/wp-content/uploads/2021/08/Climate-Benefits-of-Chesapeake-Bay.pdf