Coastal wetlands are also known as ‘blue carbon’ ecosystems. Small but mighty – they are crucial for carbon storage. Coastal wetlands cover less than 1% of the ocean and yet they store over 50% of the seabed carbon reserves¹.
As a result, blue carbon ecosystems have the potential to be the world’s greatest superhero in the fight against climate change.
This is because blue carbon ecosystems sequester carbon from our atmosphere – acting as carbon sinks.
In fact, blue carbon ecosystems sequester 2 to 4 times more carbon than terrestrial forests on an area basis.
And so, restoration and conservation efforts of coastal wetlands provide both climate change adaptation and mitigation benefits.
Mangroves are an example of a marine ecosystem that stores carbon. Mangrove habitats are also critical fish nurseries. Photo by M. Potenski
Blue carbon ecosystems remove carbon from our atmosphere and oceans and store it safely in their living biomass and soils.
However, if these blue carbon ecosystems are degraded or destroyed, they release CO² and become carbon sources contributing to climate change. A carbon source is defined as a system that emits more carbon into the atmosphere than it sequesters. For example, Australia’s largest source of carbon emission is from fossil fuel energy production.
Covering roughly 140 million hectares of Earth's surface, studies have shown that restoring and rehabilitating compromised salt and tidal marches improves their ability to store carbon.
Covering roughly 140 million hectares of Earth's surface, studies have shown that restoring and rehabilitating compromised salt and tidal marches improves their ability to store carbon.
Seagrasses cover less than 0.2% of the ocean floor but store about 10% of the carbon buried in the ocean beds each year.
Seagrasses cover less than 0.2% of the ocean floor but store about 10% of the carbon buried in the ocean beds each year.
Mangroves are critical fish nurseries and carbon sinks, and the first line of defence against storm surges.
Mangroves are critical fish nurseries and carbon sinks, and the first line of defence against storm surges.
While the protection of rainforests to mitigate climate change is well known, the role of our oceans does not get as much attention.
Did you know Australia’s blue carbon ecosystems account for 11% worldwide? We have a big role to play in protecting and restoring our blue carbon ecosystems.
If our blue carbon ecosystems are healthy they can help store carbon for millennia. But when they are damaged, they release carbon into the atmosphere and can further contribute to global warming.
Damage to blue carbon ecosystems includes:
The above impacts cause ~1% loss of total area each year. The destruction of just 1% of our blue carbon ecosystems equals 2-3 million tonnes of CO² emissions.
In Australia, we have lost half of our coastal ecosystems since European colonisation began. Meaning ~25,000km2 of marsh and mangroves and 32,000km2 of seagrasses are destroyed.
Coastal developments cause further losses each year. Between 2009-13, Queensland lost 82ha of blue carbon ecosystems annually.
Restoring blue carbon ecosystems is one of the most effective and natural solutions for carbon capture. These ecosystems capture CO² for a long period of time and so they play a major role in climate change mitigation.
Our governments, policy makers and industry practitioners must urgently preserve and restore blue carbon ecosystems.
Restoring and preserving our blue carbon ecosystems will bring many benefits to Australians and the world.
The Australian Government has developed a carbon farming method through the Clean Energy Regulator. If you are eligible to participate, you can register a project and generate carbon credits for reintroducing tidal waters onto lands by establishing coastal wetland ecosystems.
AMCS and its supporters are calling for further investment in the conservation and restoration of the UNESCO marine World Heritage sites in the Great Barrier Reef, Shark Bay and Ningaloo-Exmouth Gulf catchment areas. In addition, we need the protection of existing blue carbon habitat, as a significant opportunity to mitigate climate change, improve biodiversity and water quality entering our precious Reefs.
AMCS is also asking the federal government to accelerate the development of a quantifying methodology of ecosystem restoration, so that blue carbon can be counted towards Australia’s Paris Agreement targets. This will accelerate and further incentivise land owners to participate in restoration projects.