Valuation of blue carbon and ecological co-benefits in temperate seagrass meadows in the Atlantic Virginia Coast Reserve

Abstract

Amid growing concerns over climate change and ecosystem degradation, seagrass restoration has emerged as an effective nature-based solution with significant environmental and economic benefits. Using extensive long-term datasets and the benefits transfer method, we quantified the social value of four core ecosystem services: carbon and nitrogen sequestration, increased fisheries habitat, and avoided erosion in U.S. mid-Atlantic Virginia Coast Reserve (VCR) seagrass meadows. In addition, we evaluated key factors used in the valuation of natural capital, such as the social cost of carbon (SCC), discount rates, time horizons, and seagrass loss scenarios. Using a logistic growth model, we projected meadow expansion from approximately 2,190 ha to 10,700 ha over 100 years (2015-2115). In our Base Case using an SCC of $51 mt CO₂e⁻¹, the total societal value of all four seagrass ecosystem services over the next 30 years is estimated at $30.4 million, with an annual value (over the first five years) of $573,700 year⁻¹, or $224 ha⁻¹ year⁻¹. The present value of these services over 30 years, assuming a 3 % discount rate, is $19.1 million. Higher social costs of carbon, lower discount rates, and longer time horizons further increase present values over 100 years. As policymakers, communities, and businesses confront climate change and the loss of marine habitats, this study and associated future work highlight the importance of nature-based solutions, like seagrass restoration, in building resilient coastal economies.