Marine sinks studied
UNESCO says Australia’s unique marine habitats are some of the world’s largest stores of carbon dioxide.
A new UNESCO report has found that Australia’s six marine World Heritage Sites hold 40 per cent of the estimated 5 billion tons of carbon dioxide stored in mangrove, seagrass and tidal marsh ecosystems within UNESCO sites.
The report quantifies the enormous amounts of so-called ‘blue carbon’ absorbed and stored by those ecosystems across the world’s 50 UNESCO marine World Heritage Sites.
Despite covering less than 1 per cent of the world’s surface, blue carbon ecosystems are responsible for around half of the carbon dioxide absorbed by the world’s oceans while it is estimated they absorb carbon dioxide at a rate about 30 times faster than rainforests.
Australia’s Great Barrier Reef, Ningaloo Coast and Shark Bay World Heritage areas contained the vast majority of Australia’s blue carbon ecosystems.
“Here in Australia and around the world, these ecosystems are under threat from human development and climate change,” says report author Dr Oscar Serrano.
“While they’re healthy, blue carbon ecosystems are excellent stores of carbon dioxide, but if they are damaged, they can release huge amounts of carbon dioxide stored over millennia back into the atmosphere.”
This occurred in 2011, when seagrass meadows in the Shark Bay World Heritage Site in Western Australia released up to nine million tons of stored carbon dioxide after a marine heatwave devastated more than 1000sq km of seagrass meadows.
UNESCO says countries including Australia could use the global carbon trading market to fund conservation and restoration efforts at marine World Heritage Sites.
Dr Serrano said both Shark Bay and the Great Barrier Reef ecosystems are at risk due to climate change and human development.
“There are significant opportunities for both the Great Barrier Reef and Shark Bay to be protected and restored to ensure they survive and thrive in the future,” he said.
“Australia also has plenty of marine ecosystems in need of protection not contained within a World Heritage Site which are worthy of our attention.