How do mangrove forests remove excess CO2?

Mangroves are one of the top three carbon-capturing ecosystems on the planet, storing CO2 primarily in their distinctive soils and root systems that rise in lattices above the ground and water. Like all forests, mangroves convert CO2 — captured through photosynthesis — into leaves, wood, roots, and bark, increasing their carbon stocks in the form of biomass (living matter) as they grow. Mangrove forests have the highest total global carbon standing stock of all coastal vegetated ecosystems [1]. The rate of carbon removal per unit area is about four times higher than tropical forests and rainforests on land [2]. Moreover, carbon added through leaf litter and root growth decomposes very slowly because mangrove mud is waterlogged by the tide, resulting in carbon-rich soils that exist for hundreds to thousands of years [3]. This means when undisturbed mangrove trees remove excess carbon from the atmosphere, it gets safely locked away instead of contributing to climate change.

  1. 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.
  2. Donato D. C., Kauffman J. B., Murdiyarso D., Kurnianto S., Stidham M., & Kanninen M. (2011), Mangroves among the most carbon-rich forests in the tropics. Nat Geosci., 4(5): 293-297. doi: 10.1038/ngeo1123.
  3. Spalding, M. D. & Leal, M. (eds.) (2021), The State of the World’s Mangroves 2021. Global Mangrove Alliance. Designed and produced by MSQ Sustain.
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.