Carbon sequestration potential in constructed weatlands: a mini-review

Background: Wetlands are “high-carbon ecosystems,” covering only 5–8% of the Earth’s land surface yet storing 20–30% of terrestrial carbon. Constructed wetlands (CWs), originally designed for wastewater treatment, also provide carbon sequestration alongside biodiversity support, flood regulation, and landscape enhancement. Studies show high carbon sequestration rates (CSR) during the first 0–15ௗyears of CWs, followed by a plateau, with average carbon storage of 3.58 ± 2.21ௗkgௗCௗm⁻² (~0.12ௗkgௗCௗm⁻²ௗyr⁻¹), 92% of which is organic carbon, and mid-term rates are enhanced by macrophytes growth, among other factors. Figureௗ1 schematically illustrates plant-mediated carbon sequestration and the main carbon cycling processes in wetland ecosystems. With rising anthropogenic GHG emissions, advancing real-scale evaluations and long-term monitoring is essential to confirm CWs as a practical nature-based solution (NBS) for carbon neutrality strategies and climate change mitigation. Aim: The aim of this review is to synthesize current evidence (2021–2025) on how CWs contribute to carbon sequestration and to evaluate their potential as a NBS in climate neutrality strategies. Conclusions: CWs are a NBS that combine wastewater treatment with ecological services, notably carbon sequestration. The surge of research (77 papers, 2021– 2025) highlights their rising global importance and multifunctionality. Advancing real-scale evaluations and long-term studies will be essential to confirm their role as a practical NBS for carbon neutrality strategies.