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Oceans

The Blue Carbon Opportunity

November 2016

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Coastal wetland ecosystems—salt marshes, seagrass meadows and mangroves—play an important role as a natural solution to climate change. These coastal ecosystems sequester and store carbon from the atmosphere, often referred to as “blue carbon.” Coastal wetlands draw in carbon as they grow and transfer much of this into the rich organic soils held by their roots, with the potential to remain in the soil for thousands of years.

In addition to this mitigation potential, blue carbon ecosystems also provide critical coastal climate adaptation benefits by reducing the impacts of increasing storm surge, erosion and sea level rise. They also provide a suite of other co-benefits such as spawning grounds for fisheries, water purification and economic stimulation.

But coastal wetlands are at risk. Scientists estimate that 50% of the world’s mangroves and seagrasses, and at least 25% of the world’s tidal marshes, have been lost in the last 100 years. As a key natural climate solution, it is essential that we protect and restore the world’s blue carbon ecosystems.

The Facts:

  • 151 countries have at least one blue carbon ecosystem (seagrass, salt marsh or mangrove forest) and 71 countries contain all three.
  • 28 countries’ NDCs (or INDC if not ratified) reference coastal wetlands for mitigation
  • 53 countries include coastal ecosystems and the coastal zone in their adaptation strategies.
  • If half of the annual coastal wetlands loss was halted, emissions would be reduced by a 0.23Gt CO2 yr-1. This is equivalent to offsetting the 2013 emissions of Spain.
  • If coastal wetlands were restored to their 1990 extent, it would have the potential to increase annual carbon sequestration 160Mt CO2 yr-1 which is the equivalent of offsetting the burning of 77.4 million tonnes of coal.

A Note From Our Global Leader


Coastal wetland ecosystems can be unsung heroes in the fight against climate change. If properly managed and restored, these ecosystems have the potential to further enhance their powerful role to reduce emissions, while also protecting our coast, communities, livelihoods and economies from the impacts of climate change that many around the world already feel. Coastal countries have an opportunity to take their blue carbon ecosystems into account when considering their national level climate actions.