Final report - 2011-084-DLD -Optimising and managing coastal carbon: comparative sequestration and mitigation opportunities across Australia’s landscapes and land uses
This report summarises the ability of Australia’s coastal wetland ecosystems, particularly mangroves,
saltmarsh and seagrass to capture and store carbon. Coastal carbon capture and storage was
compared with carbon capture of Australia’s terrestrial ecosystems, including native forests,
grasslands, croplands, freshwater wetlands and agricultural land use.
It is internationally recognised that carbon sequestration, or removing carbon from the atmosphere
and storing it in vegetation and soils is a key part of the strategy to mitigate against the world’s
changing climate. The focus of Kyoto and many other international forums has been on accounting for
emissions and removals of greenhouse gases from the land, including the growth and life cycles of
forests and agricultural crops, soils, land cover change and land management.
There is evidence and growing consensus that through avoided emissions, conservation, repair and
sustainable use the world’s coastal wetland ecosystems can play a major role in carbon management.
Known as blue carbon sinks, mangroves, seagrass and saltmarsh can sequester and store carbon in
their sediments and biomass at higher rates than those of terrestrial forests. Unlike most terrestrial
ecosystems, the carbon stored in coastal wetland ecosystem sediments has extremely long residence
times, potentially for millennia.
Principal Investigator: Anissa Lawrence
Key Words: costal carbon, carbon, wetland ecosystems, mangroves, saltmarsh, seagrass, storage, carbon storage, carbon capture
Summary: Australia has yet to fully recognise the important role that coastal ecosystems can play in carbon management. Coastal ecosystems are not part of our National Carbon Accounts. The Australian Government Clean Energy Futures Package through the Carbon Farming Initiative (CFI) is only supporting farmers and land managers to earn carbon credits by storing carbon or reducing greenhouse gas emissions on the land. Coastal ecosystems are the habitats or “productive farms” for our fishers, yet the Carbon Farming Initiative specifically excludes coastal ecosystems. Through these policy limitations Australia is not only limiting its carbon management options, but is ignoring many other community benefits of food production, biodiversity, flood control, coastal buffering water quality and recreational and aesthetic benefits that coastal ecosystems provide. As a direct consequence of coastal ecosystems being omitted from Australian policy, the peer-reviewed literature relating to carbon sequestration and storage within coastal wetland ecosystems for Australia is very limited compared to that available for terrestrial ecosystems and their land-uses. Contrastingly, scientific\ understanding of carbon sequestration and potential emissions from coastal wetland ecosystems globally is much higher. This body of international knowledge is sufficient for developing effective carbon management, policy, and conservation incentives for coastal carbon in Australia.
While the data we do have is generally consistent with global estimates, it is imperative that we strengthen the evidence base (the data) in order to improve the decision making process over the broad range of “blue carbon” habitats in Australia. The recognition and management of the carbon storage and sequestration potential of these coastal wetland ecosystems provides an opportunity to strengthen socio-economic resilience of Australia’s coastal communities and estuarine and marine based industries, avoids significant emissions from ecosystem degradation, while also supporting existing wetland conservation efforts.
The newly adopted definition of wetland drainage and rewetting under the Kyoto Protocol provides an immediate incentive to account for anthropogenic greenhouse gas emissions and removals by Annex- I Parties, of which Australia is one. These represent further potential mechanisms for reducing emissions of coastal blue carbon to the atmosphere.