New research reveals the carbon-storing potential of tidal marshes

Researchers at the University of Cambridge and the Nature Conservancy led a study to model and map the global distribution of carbon stored in the world’s tidal marshes. Tidal marsh ecosystems, often overlooked in climate strategies, have immense value in carbon storage and sequestration and climate mitigation capabilities. Tidal marshes build soil and, in that soil, they trap, deposit and secure carbon. Because marsh soil is both perpetually wet and salty (muddy), the carbon does not rot as it builds up. Thus , they already store large volumes of carbon, but are also among the world’s best carbon scrubbers.  

Using training data from over 3,700 soil cores from around the world to model, analyze, and map soil organic carbon (SOC stocks) in tidal marshes, researchers estimated that 1.44 Pg of carbon (that’s 1,440,000,000 metric tons) is stored by tidal marshes globally – the carbon equivalent to the energy consumption of 700 million US homes, according to the US EPA.  

Understanding where the carbon is concentrated enables protection against further losses of tidal marshes and makes the case for increased ecosystem restoration. By supporting data-driven decision-making, this research bridges knowledge gaps, empowers countries to integrate tidal marsh conservation into their climate strategies, such as their climate commitments under the Paris Agreement, and strengthens the case for blue carbon ecosystems as a Nature-based Solution (NbS) for climate mitigation and adaptation.  

Their findings underscore the significant carbon sequestration capacity of tidal marshes, positioning them as a critical component in global climate strategies. Learn more at Cool Green Science.  

The 30m resolution map is available for viewing on Mapping Ocean Wealth and associated data can be downloaded from Zenodo. The accompanying paper can be found here.  

Cover image: © George Steinmetz