The delegates and observers at the COP16 in Cancun are getting an earful about Blue Carbon—shorthand for atmospheric carbon sequestered in the earth’s coastal and nearshore environments. Oceans Day at Cancun will feature a session on Blue Carbon, and briefs, and blogs by ocean advocates are circulating on the net and at side events. The reason for the buzz is that coastal wetlands, including tidal salt marshes, estuaries and river deltas, mangroves and sea grass beds are highly efficient at taking up CO₂ from the atmosphere and converting it into organic material—then storing it in the soil. In fact, the root systems and sediment layers which build up as this organic material is generated, broken down and deposited, are up to ten times more rich in carbon than the biomass above the surface.

 

This makes coastal wetlands even better at sequestering carbon than tropical forests. And, unlike their counterparts on land whose net growth peaks when the forest matures, wetland vegetation continues to grow and sequester carbon in the soil as long as sediments are deposited and the environment remains healthy. This is why Blue Carbon is being brought into the international dialogue on carbon emission offsets and the domain of REDD+ eligible activities. A statement, signed by 55 marine and environmental stakeholders from 19 countries has been presented to the COP for action.