Assessing the Impacts of Sea Level Rise on Blue Carbon Stocks in Long Island, New York

Blue carbon refers to carbon that is removed from the atmosphere as CO2 and sequestered in coastal ecosystems, such as mangroves, tidal marshes, and seagrasses. In tidal marshes, the vast majority of this sequestered carbon is found in the soil, where it can remain trapped for decades. Preserving coastal wetland ecosystems is therefore an important strategy to mitigate climate change and reduce the concentration of anthropogenic CO2 in the atmosphere. Sea level rise (SLR) can affect the carbon storing capacity of coastal wetlands as salt marshes migrate further inland and rising tides disturb soils that sequester carbon, potentially releasing CO2 into the atmosphere. Using a modelling-based approach, we examined how a projection of 1 m of SLR by 2100 would affect coastal wetland carbon storage on Long Island, New York with a low, medium, and high rate of carbon sequestration. Changes to tidal marsh cover were estimated using the Sea Level Affecting Marshes Model (SLAMM to map the land use/land cover changes as tidal marsh area increased under 1 m SLR. This geospatial data was then entered into the Natural Capital Project's Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST). InVEST's Coastal Blue Carbon Model to estimate the tons of carbon sequestered from 2021 to 2100 with our varying rates of sequestration. Our results indicate that, on average, 1m of SLR would reduce total carbon stocks and future carbon sequestration on Long Island by 22 million tons CO2e by 2100. In particular, our results emphasize that maintaining wetland protection and managed retreat should therefore be a priority not only for mitigating climate change