German researchers have examined the carbon storage potential of the planet’s coastal ecosystems (“blue carbon” storage), and found that Australia has the world’s largest potential for carbon sequestration. Indeed, according to their calculations, Australia’s coast provides the world with around A$30 billion, give or take $5 billion, in blue carbon storage per year.
“Marine CO2 uptake as well as its enhancement requires more attention in the debate on net-zero greenhouse gas emissions and net-negative CO2 emissions targets,” says Wilfried Rickels, a researcher at the Kiel Institute for the World Economy, Germany, and senior author on a paper describing the research, published in Nature Climate Change.
In the study, the researchers examined three widespread coastal ecosystems which are particularly valuable carbon sinks: mangroves, salt marshes and seagrass meadows.
The researchers determined the area of these ecosystems within the exclusive economic zones of every coastal country, and used this to calculate the carbon storage potential for each country.
They then assigned a monetary value to the amount of blue carbon each country stored, based on a country-specific “social cost” of carbon: in short, the contribution of both natural and human-created resources to the health, stability and thus wealth of a society.
“Most countries around the globe will face climate damage costs in the future,” explain the authors. “When ecosystems or other carbon sinks take up carbon from the atmosphere, their natural capital value increases by the shadow value of the carbon withdrawn from the atmosphere. “
In total, the researchers found that coastal ecosystems contribute US$191 billion ± $30 billion per year to the blue carbon budget (~A$255 ± $40 billion). Australia, the US and Indonesia were the biggest coastal contributors of blue carbon storage (in order), but the US was also one of the largest users of the “social cost” of carbon emissions, because of their large population size and high per capita consumption.
“If we take into account the differences in marginal climate damages that occur in each country, we find that Australia and Indonesia are clearly the largest donors in terms of globally avoided climate damages originating from coastal CO2 uptake, as they themselves derive comparatively little benefit from the high storage potential of their coasts,” says Rickels.
“The US, on the other hand, also store a lot of carbon in their coastal ecosystems, but at the same time benefit the most from natural sinks behind India and China.
“In monetary terms, the three countries realise annual welfare gains of about US$26.4 billion (India), US$16.6 billion (China) and US$14.7 billion (US) thanks to global coastal ecosystems and the resulting lower climate impact costs.”
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Ellen Phiddian is a science journalist at Cosmos. She has a BSc (Honours) in chemistry and science communication, and an MSc in science communication, both from the Australian National University.
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