Methodology

The Blue Forests Mapping Tool uses the following methodology to estimate carbon stored in marine and coastal habitats.

In order to calculate the quantity of blue carbon at each site we have used the most recent, globally consistent estimates of blue carbon storage per unit area (Table 1 below) multiplied by the area of each of the habitats in the selected areas.

The analysis is restricted to the quantity of carbon stored within the first metre of soil due to the availability of data. As such, the final values likely represent a conservative estimate of the total carbon found.

Furthermore, the limited availability of data means that the analysis does not capture spatial variability in carbon estimates between sites and geographies.

Habitat Megagrams of carbon per hectare (km2/ha) in the top 1 metre of soil Citation
Mangrove Country dependent with a global average of 2.83 Atwood, TB et al., (2017) Global patterns in mangrove soil carbon stocks and losses. Nature Climate Change 7: 523-52. DOI: 10.1038/nclimate3326
Seagrass 1.39 Fourqurean, JW et al., (2012) Seagrass ecosystems as a globally significant carbon stock. Nature Geoscience 5: 505-509. DOI: 10.1038/ngeo1477
Saltmarshes 2.55 IPCC (2013). Coastal Wetlands. In: 2013 Supplement to the 2006 IPCC guidelines for National Greenhouse Gas Inventories (eds. Alongi, D., Karim, A., Kennedy, H., Chen, G., Chmura, G., Crooks, S et al.).
Table 1. Sources of blue carbon estimates.