Wetlands revival slashes carbon emissions, could reduce drought severity

The study, published in the Journal of Environmental Management, not only shows reviving floodplain wetlands can cut carbon emissions by 39 per cent and restore critical ecosystem functions, but says the benefits can be seen within 12 months.

Lead author and research fellow in environmental sciences Dr Lukas Schuster, from RMIT University’s Centre for Nature Positive Solutions, said the scale and pace of ecosystem benefits revealed within a year of restoration provided a clear case for action.

“We found managing freshwater wetlands for carbon benefits also boosts flood and drought resilience, highlighting the mutual benefits of restoration,” he said. “We’ve shown wetland restoration pays off, so we hope this study will inform future land management policies.”

Floodplains, or riparian wetlands, comprise more than half of the world’s wetlands, but are often overlooked because of their lower carbon storage, Schuster said, when compared to peatlands, the more widely recognised carbon sinks. The problem is that peatlands can produce up to 530 per cent more methane after restoration, potentially offsetting any short-term climate benefits.

By contrast, reviving floodplains can slash emissions by 39 per cent without that methane spike, the study found.

Freshwater wetlands cover less than 10 per cent of the Earth’s surface yet contribute up to 25 per cent of global methane emissions, which is why this new discovery, indicating they could hold real potential as long-term carbon sinks, is exciting.

Speaking to the Advocate after the study’s release, Schuster said a goal of the authors “was to promote the science but also (hopefully) inform national and international policies and raise awareness among the public”.

“The reality is that there is not a lot known about the benefits of restoring non-peat wetlands, like floodplain wetlands, both in Australia and globally,” he said. “Most studies and restoration efforts to date have focused on peatlands like bogs since those are known for their significant carbon sequestration and storage potentials. But non-peat wetlands, despite typically storing less carbon, provide other important ecosystem services like water purification and flood and drought mitigation – and our restored wetlands showed increased nitrogen cycling and they retained more soil moisture after drying up, which is indicative of the reinstatement of such critical ecosystem services within just one year of restoration.

“We’re hoping that our findings are a bit of a wake-up call for policymakers, so that more effort will be put into restoring but also protecting these critical ecosystems in Australia and around the world.”

The study’s release coincidentally coincided with the Victorian National Parks Association pushing for further protection for important wetlands in Hastings, where Australia’s Environment Minister Murray Watt has just announced plans for a planned energy terminal to be declared “a controlled action” under federal nature laws.

The Minister’s decree means the project must now undergo a comprehensive environmental assessment to decide whether it can be built without damaging endangered wildlife and habitats in the Ramsar-listed wetlands.

The VNPA is still not entirely happy, saying even with the newly reduced scope of dredging and wetland loss, the Victorian Renewable Energy Terminal was still being planned in the wrong place.

“We are still yet to be presented with convincing rationale for why this terminal must be built in the heart of a UNESCO Biosphere reserve and Ramsar-listed wetland,” said VNPA marine campaigner Shannon Hurley.

“We want certainty that the project can be done in a way that doesn’t cause unacceptable harm to the Western Port wetlands, and we aren’t confident that has been achieved yet.”