What is blue carbon?

Blue carbon refers to carbon stored by coastal and marine ecosystems, mostly through plant growth and by accumulating and burying organic matter so it can’t decompose and release carbon dioxide. Some examples of blue carbon ecosystems are mangroves, saltmarshes, supratidal forests and seagrass meadows.

There’s increasing interest worldwide in protecting and restoring these blue carbon ecosystems, because of their potential for helping tackle climate change – while also creating substantial benefits for biodiversity and human livelihoods.

Underwater seagrass meadows are an example of blue carbon ecosystems. Here, we see skinny, light green grass swaying in the dark blue ocean water, with a small grey and yellow toadfish in the foreground.

Seagrass meadows like this are examples of blue carbon ecosystems.


How much carbon can these ecosystems store?

Research about their carbon storage potential is ongoing, but most sources agree these ecosystems are among the most efficient natural carbon sinks, capturing and storing carbon two to four times faster than terrestrial forests.

Besides storing carbon, healthy and thriving blue carbon ecosystems are also important for helping communities, nature and the economy bounce back from climate change impacts. An example of this is the potential of mangrove and coastal saltmarsh ecosystems for reducing the impacts of storm surges and sea level rise on coastal communities.

A large, tall tree covers the bright sunshine over a pristine blue and green wetland ecosystem.

Coastal ecosystems – like the wetlands here at Mungalla Station in Queensland – are under pressure globally. Credit: Story in Progress.

Unfortunately, blue carbon ecosystems like mangroves and wetlands tend to be misunderstood and are under pressure globally from coastal development, agriculture and aquaculture, and pollution. Their high carbon content means that their degradation and destruction is a significant source of global carbon dioxide emissions.

Conserving and restoring our coastal and marine ecosystems, and appropriately recognising their global and local value, are therefore key nature-based solutions in the global effort to tackle the climate crisis.

So, who’s going to pay?

Just as carbon credits can drive private investment in conservation and restoration of native forests, expanding the carbon market to include blue carbon methodologies could do the same for accelerating coastal ecosystem restoration.

The significant co-benefits from blue carbon projects, in terms of supporting biodiversity and people’s livelihoods, may make them attractive to impact investors and drive demand, while those who take steps to restore blue carbon ecosystems (like private landholders) would be rewarded for their efforts with an alternative source of income.

Blurred people in the foreground with a light green and blue backdrop of wetlands at Mungalla Station.

There is increasing recognition of blue carbon as a viable natural climate solution and impact investment – for both people and nature. Credit: Cait Miers.

In Australia, the first step has been taken. As of January 2022, the Australian Government’s Clean Energy Regulator approved the first method to create blue carbon credits in Australia: tidal restoration of blue carbon ecosystems.

This means that projects to remove barriers such as weirs, bunds and regulators and restore natural tidal movement in coastal areas can register to be issued with Australian Carbon Credit Units for the carbon being stored in the vegetation (such as mangroves and saltmarshes) and mud.

The inclusion of blue carbon in the global carbon market is in its infancy. However, there is significant willpower worldwide to address barriers and uncertainties to help realise the full potential of blue carbon conservation and restoration as a viable natural climate solution and impact investment – for both people and nature.

What does blue carbon have to do with Greening Australia?

Rebuilding nature – including coastal and marine ecosystems – is Greening Australia’s mandate and mission.

The strongest connection between our work and blue carbon can be found in our Reef Aid program, which works in collaboration with Traditional Owners, landholders, scientists and other stakeholders to restore wetlands, swamp forests and saltmarshes and reduce sediment and nutrient run-off to improve water quality for the Great Barrier Reef ecosystem (including its seagrass meadows).

Greening Australia, nature-based solutions company Canopy and Mungalla Aboriginal Business Corporation have won an Australian Government grant to explore the feasibility of a blue carbon project from tidal wetland restoration at Mungalla Station on Nywaigi Country in Queensland. If successful, the project would also provide a long-term income stream to benefit the Nywaigi People.

A light blue and turquoise aerial shot of coral from the Great Barrier Reef.

What happens on land affects what happens at sea. Restoring wetlands and reducing sediment and nutrient run-off improves water quality, supporting the health of the entire Great Barrier Reef ecosystem.

Our restoration of coastal ecosystems is not restricted to the Great Barrier Reef catchments alone. For example, we were part of a state-government-funded project secured by Deakin University to establish best practice saltmarsh restoration guides in Victoria, providing a demonstration site in the Gippsland Lakes by undertaking restoration in partnership with a local landholder that has 100 hectares of saltmarsh on their property.

As an island nation with one of the longest coastlines of any country in the world, we believe Australia has both a responsibility and an exciting opportunity to contribute to tackling global climate change and biodiversity loss by conserving and rebuilding our blue carbon ecosystems – connecting community, economy and the environment in ways that benefit all.

Our Reef Aid program