Blue carbon potential from rehabilitating urban mangrove forests in coastal city

Abstract

Mangrove forests are critical coastal wetlands for the global blue carbon budget and play a significant role in mitigating climate change. Therefore, accurate and reliable assessments or predictions of mangrove blue carbon are essential to support the implementation of mangrove restoration projects and to underscore their importance. However, current evaluations of mangrove restoration outcomes, particularly regarding the carbon dioxide removal (CDR) potential of these forests, remain inadequate. This study aims to investigate the impact of mangrove restoration on blue carbon and CDR in Xiamen City, located in the southeastern coastal region of China. Specifically, the study seeks to quantify the carbon stocks of mangrove forests at present and in the future and to evaluate the contribution of mangrove restoration to achieving carbon neutrality and peak carbon emissions. Field investigations and soil sampling were conducted in 2022 to establish a biomass carbon prediction model and to assess mangrove blue carbon. The average mangrove blue carbon is currently estimated at 89.27 MgC ha⁻¹, and it is projected to increase to 112.07 MgC ha⁻¹ by 2030 and to 173.26 MgC ha⁻¹ by 2060. Additionally, this research evaluates the CDR by offsetting the net carbon gain against greenhouse gas (GHG) emissions, highlighting not only the significance of non-CO₂ GHGs in the mangrove carbon budget but also providing a robust foundation for the conservation and management of mangrove ecosystems, particularly in their capacity for carbon sequestration and their role in mitigating climate change.