Assessing the contribution of Tidal Flats to climate change and carbon neutrality through modeling approaches

Tidal coastal ecosystems show promising potential as natural carbon sinks in mitigating climate change. Under the combined effect of carbon deposition, capturing, converting, and storing atmospheric CO₂ into coastal sediments over a long period, tidal flats are of great significance to the ecology. In addition to preventing coastal erosion, the organic carbon buried in tidal flats should play an important role in mitigating climate change and achieving the carbon neutrality target. However, although the growing interest in tidal flat carbon has prompted studies to estimate carbon stocks at the global level in general and Korea in particular, comprehensive assessments of the role of carbon stocks in climate change have yet to be made. Therefore, the present study aims to quantify and simulate organic carbon stocks in tidal flats habitats of the Korean coast through a carbon balance model, thereby assessing their role in climate change and carbon neutrality. Biomass vegetation, meteorological, and sedimentary data up to 70 cm depth were sampled from 37 sites representing tidal flats along the Korean coast and then applied to the model to simulate the carbon sequestration rate as well as to provide predictions of sediment carbon stocks until 2050. The study revealed that the average total organic carbon (TOC) storage in vegetated and non-vegetated tidal flats reach 53.41 Mg C ha^-1 and 45.48 Mg C ha^-1 up to a depth of 70 cm in 2050, respectively, of which vegetation on the ground accounts for 3.06 ± 3.01 MgC.ha^-1. Carbon mass is found to increase linearly over time in nearly all areas studied, with carbon sequestration rates ranging from 0.037 to 0.71 (MgC ha^{- 1} yr^{- 1}). The Korean tidal flats contain 11,200,000 MgC (∼4.13 × 10⁷ tCO₂ eq) of organic carbon (70 cm depth). This clearly reflects their potential for inclusion in the Nationally Determined Contribution (NDC) under the Paris Agreement. Model simulation result indicated that the topsoil carbon mass of Tidal Flats in the year 2050 could contribute 7.64 × 10⁶ tons CO₂eq towards the "2050 carbon neutral strategy of the Republic of Korea". The findings of this study shall strengthen the knowledge base regarding Korea's Tidal flat carbon stocks as well as their potential role in mitigating climate change and contributing to future carbon neutrality goals.