Quantifying carbon sequestration capacity of potential wetland restoration in South Korea using a high-resolution dynamic vegetation model

Wetlands are recognized as critical carbon sinks and effective nature-based solutions for climate change mitigation. However, in many regions, wetland areas and their functions have significantly diminished due to agricultural expansion and land-use changes. This study aimed to identify potential wetlands based on a topo-climatic index and quantitatively assess the carbon sequestration capacity of restoring these areas­–currently used croplands–back to wetland ecosystems. We employed LPJ-GUESS, a process-based dynamic global vegetation model (DGVM) with ERA5-Land reanalysis climate data at a 0.1^o resolution for the period 1950–2024 (75 years) and land use maps constructed based on Landsat images. To quantify the carbon benefits, we performed a comparative analysis between two scenarios: a baseline scenario maintaining current land use, and a restoration scenario where potential wetlands within agricultural lands are reverted to natural wetlands. Results indicate that at the national and regional scales, the difference of net ecosystem-atmosphere exchange (NEE) between two scenarios (Δ_NEE) appeared minimal. This is likely because the restoration effects were limited by spatial averaging, as the proportion of restored wetlands remained below 5% at these national or regional scales. In contrast, at the single-pixel scale (0.1^o) where the wetland restoration ratio reached approximately 35%, the carbon sequestration effect was significant, showing an increase of up to 0.37 kgC m^-2. This suggests that wetland restoration can serve as an effective nature-based solution in croplands adjacent to rivers. However, given that the full carbon sequestration potential of wetlands often manifests over timescales exceeding a century, our 75-year simulation provides a conservative estimate. Therefore, we emphasize the necessity of long-term simulations incorporating future climate change scenarios to comprehensively evaluate the sustained efficacy of wetland restoration.

Acknowledgements: This work was jointly supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (RS-2024-00416443), and by the Korea Environmental Industry & Technology Development Project, funded by Korea Ministry of Climate, Energy and Environment (MCEE) (RS-2022-KE002066).