Blue carbon climate fix to be a green boon for coastal communities
Hidden in our seagrass, mangroves and saltmarshes is a little-known ability – to capture and store more carbon than the plants on dry land. SA is well set up to protect and expand these ecosystems – and it’ll make money in the process.
SA News
Don't miss out on the headlines from SA News. Followed categories will be added to My News.
- It’s the role of corporations to stop climate change, not individuals
- See this month’s subscriber rewards
Have you heard of blue carbon?
It’s a term used for carbon that is captured and stored in the plants, soil and sediments of coastal ecosystems. Think seagrass, mangroves and tidal saltmarshes.
Plants growing in these watery places capture and store more carbon than plants on dry land, at a faster rate. And the carbon is stored for longer: hundreds or thousands of years.
There’s enormous potential for blue-carbon projects to reduce greenhouse gas emissions and provide many other benefits at the same time.
A report soon to be released by the Goyder Institute for Water Research contains the most comprehensive data available on blue-carbon opportunities in South Australia.
The State Government is developing a blue-carbon strategy for SA, through the Environment and Water Department and the Premier’s Climate Change Council.
The department says the strategy will describe how to establish statewide, evidence-based projects and research geared towards blue-carbon ecosystem protection and restoration.
Based on a carbon trading price of $12 a tonne, blue-carbon projects are potentially worth tens of millions of dollars a year in payments from the Australian Emission Reduction Fund and voluntary carbon markets.
But the fund currently only includes land-based methods for carbon sequestration, which are essentially green carbon projects.
The Federal Government is assessing the feasibility of developing blue-carbon methods, spurred on by research scientists.
As usual, SA is not waiting for the Commonwealth to act because these projects make sense for so many reasons.
University of Adelaide research associate Dr Alice Jones says it might take another couple of years to get the systems in place but “there will be a way for industry and individuals to claim carbon credits based on the restoration of blue carbon ecosystems”.
“Now that there’s a lot of information out there, saying that these systems do store a considerable amount of carbon and they do have real benefits for mitigating climate change, that builds confidence,” she said.
“People will start setting up projects in these ecosystems, restoration projects that can also get carbon credits but as well have so many other benefits for people and the natural world as a whole because they provide so many ecosystem services.
“They’re important nursery areas for fisheries and they have water filtration benefits, they stabilise coastlines, provide storm surge protection and all of these other benefits as well as recreational – providing places for people to spend time in nature.”
A spokeswoman for the department said the best locations for blue-carbon projects were areas that could capture and store a lot of carbon and are also in need of restoration or protection.
“Blue-carbon projects provide a range of benefits, such as protecting shorelines from sea-level rise, improving water quality, and providing habitat for fisheries and migratory birds, for example the Adelaide International Bird Sanctuary National Park, Winaityinaiyti Pangkara, to the north of Adelaide,” she said.
“Ideally, blue-carbon project sites can help reduce emissions but also contribute to the state’s tourism industry and support regional economies and coastal livelihoods.”
The State Government is investing $1 million in seagrass restoration, experimenting with the homegrown technique of placing hessian bags on the sea floor for young seagrass to attach.
The technique is the basis of a restoration project to re-establish about 10ha of seagrass off the Adelaide metropolitan coastline.
Trials are taking place at pilot sites this year and large-scale restoration work will follow next year.
Over the past half-century, about one third of seagrass along the Adelaide metropolitan coast has been lost, so there’s plenty of scope to expand the restoration project.
University of Adelaide Professor Bronwyn Gillanders led the Coastal Carbon Opportunities project with colleagues from Edith Cowan University, SA Water, SA EPA and CSIRO.
The team mapped the whole state to provide accurate area estimates of blue-carbon ecosystems, finding SA has more than one million hectares of seagrass, close to 20,000ha of tidal saltmarsh and 16,420ha of mangroves. That adds up to 1.12 million ha of blue-carbon ecosystems.
That area was estimated to be able to accumulate or sequester between 0.36 and 0.83 million tonnes of CO2 every year, which is up to 3.6 per cent of the state’s annual greenhouse gas emissions.
The team looked at three case studies: seagrass at Port Broughton, seagrass around Semaphore and mangroves at Outer Harbour and Torrens Island. They confirmed that far more carbon was stored in healthy ecosystems than degraded ecosystems.
Meanwhile, Flinders University Professor Sabine Dittmann explored the potential for carbon sequestration through ecological restoration at the Dry Creek Salt Field. She reintroduced tidal flows to one area, with strong positive effects.
The climate change director in the coast and marine section of the Environment and Water Department, Dr Neil McFarlane, says the research has contributed substantially to understanding the potential of blue carbon in SA.
“This Goyder project is a good example of applied research informing policy development and the team has also provided further recommendations to identify critical knowledge gaps and propose further research,” he said.
Research published this week in the journal Nature Communications provides the national evidence base for the Commonwealth to proceed with the development of blue carbon projects.
This quantification of Australia’s blue carbon is the most accurate of any country and paves the way for conservation and restoration of these ecosystems to be counted toward the country’s commitments to emissions reductions such as the Paris Agreement.
The international team, led by Edith Cowan University researchers, found Australian seagrass, mangrove and salt marshes absorb 20 million tonnes of CO2 each year. That’s about the same as the annual emissions of four million cars.