And why it’s imperative to protect this precious resource
Blue carbon is the name for carbon captured by oceans and coastal ecosystems. Carbon sequestration and storage in mangroves, salt marshes and seagrass meadows is an essential coastal ‘blue carbon’ ecosystem service for climate change mitigation. The marine environment – the oceans and their diverse coastal ecosystems – stores and cycles an estimated 93 percent of the Earth’s carbon dioxide.
Oceans
The ocean itself can capture and store carbon in a number of ways, such as
- Open ocean via deep-water carbon cycles
- Kelp, red algae, seagrass, and other ocean flora
- Seabed sediments
- Fish and other ocean fauna, including whales
Wetlands
Mangrove swamps, seagrass meadows, and tidal marshes are important carbon sinks. Taken together they sequester (take in) and store carbon at a rate 10 times faster than mature tropical forests. These coastal wetlands also provide protection against erosion, rising tides and storms. Unfortunately, these coastal wetlands are disappearing four times faster than mature tropical woods.
The Threats
The marine environment is under threat. They are disappearing for a number of reasons and that means the stored carbon is released back into the atmosphere as a greenhouse gas. Drivers of the loss include both natural, and predominantly human intervention. Five principal reasons for the loss are:
- Plastics
- Pollution, runoff and industrial waste
- Overfishing and dredging
- Ocean warming and acidification
- Habitat destruction (fires, flooding, construction)
Research estimates that as much as one billion tons of carbon dioxide are being released annually from degraded coastal ecosystems – equivalent to nearly 20 percent of emissions from tropical deforestation globally. This is very significant.
Looking Ahead
Without immediate intervention we are at risk of not just continuing the release of carbon, as a greenhouse gas, back into the atmosphere but destroying sensitive ecosystems and their abundant biodiversity, all that play an important role in keeping these places in a healthy balance for nature and humanity alike.
A Success Story
The good news is that we can restore these places with concerted efforts. One such example is how local communities in Senegal are restoring and protecting mangrove stands, and in turn reaping the ecosystem and financial benefits in an equitable manner. We are looking to such projects as models for other at-risk coastal communities facing the climate crisis around the world.
Such initiatives demonstrate that with adequate restoration and protection we can allow these natural spaces to do what they are meant to do – to provide ecosystem benefits, such as biodiversity and fresh water, along with economic benefits, in balance with the people who manage and care for them.
Blue Carbon Wealth
There is a tremendous amount of wealth in blue carbon as a result of its carbon sequestration. For instance, mangroves are estimated to be worth at least US $1.6 billion each year in ecosystem services that support coastal livelihoods and local communities around the world.
This same report estimates, and concedes that it is conservative, that blue carbon could be worth US$ 160 – 220 billion per year. Australia (the largest), Indonesia, and Cuba are the three countries that generate the largest positive net blue wealth contribution for the rest of the world.
Restoring and preserving the oceans and coastal ecosystems is a huge and complex undertaking. It will require many actors on all levels working in a purposeful and sophisticated fashion. Finding what works and scaling successful nature-based programs from the local communities to regional and national governments – that won’t be easy.
