How can coastal and marine ecosystems help fight climate change?

Blue carbon ecosystems (coastal wetlands such as mangrove forests, seagrass beds, and tidal marshes) are considered a key component of nature-based solutions (NBSs) to climate change thanks to their great ability to pull carbon dioxide (CO2) out of the air, via photosynthesis, and store it for long periods of time. In fact, they capture more carbon per unit area each year than most land-based forests [1]. This is partly due to their high “primary productivity” (the speed at which a plant turns solar energy into organic substances), but mainly because their plant roots are particularly efficient at trapping organic matter [2]. Additionally, carbon in underground soils and sediments, accounting for 50% to 90% of coastal wetland carbon stocks, can accumulate over hundreds to thousands of years and be locked away for millennia [3]. Furthermore, blue carbon ecosystems make a positive contribution to climate change adaptation by reducing wave energy, protecting shorelines from erosion, storms, and sea level rise, and buffering ocean acidification.

1. Mcleod, E., Chmura, G. L., Bouillon, S., Salm, R., Björk, M., Duarte, C. M., Lovelock, C. E., Schlesinger, W. H., & Silliman, B. R. (2011), A blueprint for blue carbon: toward an improved understanding of the role of vegetated coastal habitats in sequestering CO2. Frontiers in Ecology and the Environment, 9: 552-560. doi: 10.1890/110004.
2. Duarte C. M. , Losada I. J. , Hendriks I. E. , Mazarrasa I., & Marbà N. (2013), The role of coastal plant communities for climate change mitigation and adaptation. Nat Clim Chang, 3(11):961-968. doi: 10.1038/nclimate1970.
3. Duarte C. M., Middelburg J. J., & Caraco N. (2005), Major role of marine vegetation on the oceanic carbon cycle. Biogeosciences, 2(1):1-8. doi: 10.5194/bg-2-1-2005.

About the author

Vasiliki I. Chalastani is a PhD candidate at the Laboratory of Harbour Works, National Technical University of Athens (NTUA), Greece. Her thesis, “Optimization Approaches for Marine Spatial Planning,” aims to develop tools for optimal use of the marine environment through reconciliation of human activities and conservation features. Previously, following her undergraduate studies as a civil engineer at NTUA, Chalastani pursued her MSc, “Water Air Pollution and Energy at Global and Regional Scales,” at École Polytechnique, Paris, France. While in France, she has completed an internship at the Laboratoire Océanographique de Villefranche and at École Normale Supérieure on ocean-based solutions. From 2018 to 2019, Chalastani acted as a consultant for the Alternate Minister of Maritime Affairs and Insular Policy of Greece, Nektarios Santorinios. In 2018, she worked for the Institute for Sustainable Development and International Relations (IDDRI), Paris, with Alexandre K. Magnan, on the issue of climate change adaptation. In 2019, Chalastani worked for the Saudi Red Sea Project, developing a preliminary marine spatial planning initiative, under the supervision of Carlos M. Duarte. She is a member of the National Chamber of Engineers and the United Nations Sustainable Development Solutions Network (UN SDSN), Greece.