Seagrass ‘stores $79 per ha of carbon’
THEY’VE been quietly storing carbon dioxide for decades without
causing a fuss or charging anyone a cent for the privilege but Australia’s seagrass beds are at risk of being destroyed by climate change, a think tank says.
Sea grasses store 10 to 40 times as much carbon per hectare as forests, and
Australia’s sea-grass meadows are the largest in the world, a report by the
Centre for Policy Development says.
Considering the Gillard government wants to charge $23 per tonne of carbon
emitted by Australia’s biggest polluters, that would make Australia’s coastal
seagrass beds worth $79 per hectare, the report’s authors added at its official
To some extent, the carbon has been absorbed without there being any damage
to ecosystems, says Caroline Hoisington, co-author of Stocking Up: Securing our
“A lot of biological systems in the ocean sequester carbon,” she said at the
launch of the report today.
“There is nothing wrong with that. It encourages growth.
“The problem is when there is so much carbon that it can’t be sequestered,
and it starts to change the chemistry of the water in the ocean, making it more
acid, and that starts to inhibit coral growth, and that is a big worry.”
For this reason, companies that emit carbon should not think of the ocean as
a sink where it can be dumped.
“It’s more about recognising the value that it has played so far,” fellow
report co-author Laura Eadie said.
Ocean ecosystems add an extra $25 billion to the national economy each year
which is not accounted for in official figures, the report says.
These includes $15.8 billion a year in carbon storage.
It was also of concern that 29 per cent of the world’s sea grass beds had
vanished since 1879.
“Australia has the world’s largest sea beds, but warming ocean temperatures
have resulted in loss,” Ms Eadie said.
In Western Australia, about 1,000 hectares of sea grass were lost after a
particularly warm summer, Ms Hoisington added.
“That is likely to increase,” she said.
Land based pollution had also contributed to the loss of the sea grass
The report, Stocking Up: Securing Our Marine Economy, is the first
in a series looking at how different sectors of Australia’s economy can benefit
from policies to preserve the environment and the resources that sustain
Aside from warning of a decline in the number of seagrass beds, the report
recommended building up fish stocks and creating more marine parks to buffer
ocean ecosystems from the climate change affects of acidity and rising