Australian mangrove. Image Credit: Pixabay

Protecting the world’s mangroves is critical to intercepting climate change

  • BY Angela Heathcote |
  • June 27, 2017

A unique environmental lung, mangroves store thousands of years of carbon, making them irreplaceable.

BY ASSESSING THE GLOBAL distribution of carbon storage in mangroves, scientists have discovered that the destruction of various tracts has resulted in the release of millions tonnes of CO2 per year, which could bolster the effects of climate change.

Deforestation and land development, such as the creation of soils for aquaculture ponds disturbs the carbon sequestration capacity of these intertidal forests by digging up the soils that scientists say contains thousands of years of carbon, which is then exposed to oxygen and released back into the atmosphere.

The study, led by Trisha Atwood from the University of Utah, and conducted on behalf of the CSIRO Coastal Carbon Cluster, published yesterday in Nature Climate Change, was a large data analysis of mangroves and their carbon storages across multiple countries.

Jeff Kelleway, a postdoctoral research fellow from Macquarie University, who was a co-author of the study, told Australian Geographic that mangroves are unique in the way they store carbon.

“All the organic material that gets stored below ground in the roots and in the soil is protected by the chemistry of marine waters that inundate mangroves and so it has really slow decay rates. This also means that there can be hundreds and thousands of years of carbon stored in just a metre of soil.”

Assessments of mangrove soil and the amount of carbon stored in each deposit will “identify hotspots for priority conservation” for countries with the highest potential CO2 emissions from soils such as Indonesia and Malaysia, the report said.

In Australia, the situation isn’t nearly as dire, as the country manages mangrove sites through legislation including the Fisheries Act 1994 in Queensland, and the Wildlife Conservation Act 1950, in Western Australia.

“We’re fortunate in Australia in that most states and territories have good protections for mangroves. It’s quite hard to clear a mangrove forest to build a new marina or some other activity,” Jeff told Australian Geographic.

“We understand their importance to fishery production, the protection from storms and cyclones and increasingly, what they do with carbon. We don’t see the rates of deforestation and degradation that other parts of the world are seeing.”

However Jeff explains that while Australia has strong legislation, we still need to keep an eye on the mangroves in northern Australia and any intended developments of this area, as these particular deposits experienced immense diebacks in July last year.

“There are some huge fantastic mangroves up there and we need to ensure that they’re protected into the future. We also need to understand what climate change and sea-level rise are doing to our mangrove forests and what this means for carbon storage,” Jeff added.

The researcher also explained that including mangroves, salt marshes and sea grasses in the Government’s carbon abatement scheme could be worthwhile.