Despite 'Enormous Potential' as Carbon Sink, Australia's Damaged Coastal Ecosystems Spewing Millions of Tons of CO2
Australia’s seagrass meadows, mangroves, and salt marshes absorb and lock away about 20 million tons of carbon dioxide each year, but damage to these vegetated coastal ecosystems is releasing three million tons of CO2 back into the atmosphere and limiting their potential to prevent more planetary heating, according to a new study.
“Australia is home to around 10 percent of the world’s blue carbon ecosystems, so there’s enormous potential for us to take a lead role in this space.”
—Oscar Serrano, ECU
The “world-first research” on blue carbon—or carbon captured by the ocean and coastal ecosystems—was published Tuesday in the journal Nature Communications. The study, entitled Australian vegetated coastal ecosystems as global hotspots for climate change mitigation, makes a case for restoring these areas across the globe to help combat the human-caused climate emergency.
The research brought together dozens of scientists from 33 institutions worldwide—including lead author Oscar Serrano, a fellow at the Center for Marine Ecosystems Research at Edith Cowan University’s (ECU) School of Science in Australia.
“Australia is home to around 10 percent of the world’s blue carbon ecosystems, so there’s enormous potential for us to take a lead role in this space,” Serrano said in a statement from ECU. “Australia is in a position to take a leading role in developing policies to offset greenhouse gas emissions which can then be implemented around the world.”
The researchers found that Australia’s coastal zones capture about the same amount of carbon each year as the annual emissions of more than four million vehicles. However, Serrano said, “when these ecosystems are damaged by storms, heatwaves, dredging, or other human development, the carbon dioxide stored in their biomass and soils beneath them can make its way back into the environment, contributing to climate change.”
Highlighting the importance of blue carbon ecosystems, the ECU statement noted:
- Vegetated coastal ecosystems absorb carbon dioxide at rates up to 40 times faster than terrestrial forests mainly due to their enormous capacity to store carbon in soils.
- In Australia it’s estimated there is four times more carbon sequestered in soil beneath marine ecosystems over a given area than in terrestrial environments.
- Vegetated coastal ecosystems account for 50 percent of carbon dioxide sequestered by the oceans, despite covering just 0.2 percent of its total area.
Serrano pointed out that “globally, vegetated coastal ecosystems are being lost twice as fast as tropical rainforests despite covering a fraction of the area.” He added that “these ecosystems are also important as habitats and nurseries for fish and other marine life, helping prevent coastal erosion and improving water clarity.”