Climate Change Strategy Phase 1: MidCoast Council
8.10 Sequestration
Description
The MidCoast region of NSW has high potential for carbon sequestration through its extensive vegetation cover and coastal wetlands. The total area of the MidCoast is just over 1,000,000 hectares (ha), which includes: • •
23,266 ha of coastal wetlands (2% of the LGA), and 635,651 ha vegetation cover (63% of the LGA).
Increased coverage and management/restoration of vegetation and wetlands provides an opportunity for increased carbon sequestration in the region. Wetlands The MidCoast is home to 23,266 ha of coastal wetlands. Council has acquired and remediated around 5,160 ha of coastal wetlands to date, and is working to increase this to more than 6,000 ha in the near future. Coastal wetlands are generally known to be 10 times more effective at sequestering carbon than other forest vegetation types 38 . Seagrass beds, mangroves and saltmarshes store large amounts of carbon. They draw in carbon as they grow, and much of this is later transferred into the rich organic soils held by their roots. That carbon can remain in the soil for thousands of years, making wetland protection, management, and restoration important long-term natural climate solutions. Recent research published in Geophysical Research Letters39 reports on studies of two hydrologically restored freshwater coastal acid sulfate soil (CASS) wetlands located in MidCoast at Cattai and at Darawakh wetlands and restored by MidCoast Council. This reports organic carbon accumulation rates of, on average 0.24 kg per square metre per year. Extrapolated on a simple basis to the whole LGA, this suggests the following approximate sequestration rates: • • •
200,000 tonnes of CO2 per year across all wetlands in MidCoast, 45,000 tonnes of CO2 per year in wetlands already restored by Council, 7,500 tonnes of CO2 per year in wetlands Council is set to acquire and remediate in coming years
Considering emissions by Council’s operations and waste, and by the MidCoast community as a whole, ’blue carbon’ sequestration through restoration of the region’s coastal wetlands is a potentially significant part of any strategy for achieving net zero emissions in line with science.
38
https://climatechange.lta.org/wetlands/ Brown, D. R., Johnston, S. G., Santos, I. R., Holloway, C. J., and Sanders, C. J. (2019). Significant organic carbon accumulation in two coastal acid sulfate soil wetlands. Geophysical Research Letters, 46, 3245–3251. https://doi.org/10.1029/2019GL082076 39
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