Mangroves better at storing carbon than rainforests; rehab could lead to carbon offsets, experts say

Stephanie Zillman ABC News 18 May 17;

When it comes to conserving Australia's natural landscape, our boggy, mosquito-laden mangrove forests haven't always been first in line.

Coastal wetlands suffer an image problem in the eyes of the public, says Dr Kerrylee Rogers, an ARC future fellow at the University of Wollongong's School of Earth and Environmental Sciences.

"They've got a bit of a perception problem and they really need to be reframed in the context of the benefits they provide."

Dr Rogers said coastal wetlands actually play a more important part in reducing greenhouse gases than inland rainforests.

Researchers are currently building a case for including the carbon stored in coastal wetlands in the emission reductions fund.

This would mean that one day soon, Australia is likely to have another source for offsetting carbon emissions.

Across the country, but especially in the eastern states, there has been significant degradation of mangrove forests, through both real estate developments and conversion to other land uses.

"This has meant there's been a lot of loss of coastal wetlands, and the result of that has been a loss of carbon," Dr Roger said.

Opportunity to offset emissions for carbon credits

Charles Darwin University PhD student Clint Cameron is specialising in building the business case for greater investment in mangrove rehabilitation.

"The idea that we're thinking is if you're a businessman, and you want to get the most bang for your buck, we're trying to say, 'invest in mangrove rehabilitation rather than rainforest preservation, because you're going to get more carbon returns per unit area over time'," Mr Cameron said.

Mr Cameron is basing his research on a test site in Indonesia, where mangrove forests have been totally degraded due to short-term, and now defunct fish ponds.

He wants to show the potential revenue that can be created through carbon credits if the mangrove sites are rehabilitated.

"[And] if just a small portion of any revenue generated could go back to coastal communities — to people actually living in and using those resources — then that's an option that they never had before, and that's a livelihoods diversification option that didn't exist.

"It's a win-win, really."

Mr Cameron is adding to an increasing body of research that is demonstrating how much carbon is pumped into the atmosphere by the creatures that live in the rich wetlands soil long after the mangroves are gone.

He said he had measured the accumulation of greenhouse gases over time from an individual mud-dwelling creature, and the amount of carbon emitted was "incredible".

"I just simply didn't expect the volume of the carbon that was going to be emitted from these creatures, like mud lobster, for instance."