Researchers unite to protect wetlands, Earth’s ‘green lung’

Universities and environmental organisations in Southeast Asia are spearheading a campaign to protect the region’s wetlands – mangroves and peatland – which they call the world’s ‘green lung’, with recent research finding that they play an outsize role in reducing greenhouse emissions.

Southeast Asia is home to some of the world’s largest areas of tropical peatlands and mangroves, or 5.4% of the region’s land area.

When these are disturbed – often due to land use change – they release large quantities of carbon into the atmosphere which, in time, can exacerbate climate change. New research has found that half of land-use carbon emissions in the region can be mitigated through peat swamp forest and mangrove conservation and restoration.

“Southeast Asia’s peatlands and mangroves function as a ‘green lung’ because they are highly efficient carbon sinks, storing vast amounts of carbon while also playing a critical role in regional climate regulation,” said Associate Professor Massimo Lupascu, interim director of the National University of Singapore (NUS) geography department’s graduate programme in climate change and sustainability.

“Although they occupy only 5.4% of the region's land area, they store approximately 25% of global tropical forest carbon stocks, making them disproportionately important in global carbon sequestration,” he told University World News.

Researchers in the region led by Lupascu and including academics from NUS’ Environmental Research Institute (ERI), Singapore’s Nanyang Technological University (NTU), and Australia’s James Cook University calculated that of the carbon emissions that can be avoided and removed by peat forests and mangroves, 86% will come from conserving and protecting untouched habitats, while the remaining 14% would be from restoring degraded habitats through replanting.

Their research highlights the immense climate benefits of protecting these ecosystems.

In findings recently published in the academic journal Nature Communications, they calculated that conserving and restoring these habitats can reduce about 770 megatonnes of CO equivalent annually.

Indonesia accounts for the largest portion of the region’s emissions from these sources, accounting for 73%, followed by Malaysia at 14%, Myanmar 7%, and Vietnam 2%.

The other seven Southeast Asian countries generate the remaining 4% of emissions. However, the paper notes that “great potential exists for emissions reduction through PSFs [peat swamp forests] and mangrove conservation”.

“Degradation of peatlands can have serious impacts on water resources and climate in general,” the ERI states on its website, noting that the integrated research team was formed by NUS, working with other universities and regional partners such as the Indonesian Institute of Science (LIPI) and Singapore’s Delft Water Alliance, “to establish a knowledge-based platform [that would be] useful for environmental mitigation, conservation, and sustainable development of regional resources”.

Calculating emissions changes

Lupascu said their study estimated emissions using a combination of satellite data, carbon flux measurements, and established emission factors.

“We tracked land-use change from 2001 to 2022, overlaying peatland and mangrove maps with deforestation datasets to assess how much area has been lost or degraded,” he said.

“The carbon stock difference approach calculates emissions by measuring changes in carbon storage before and after land-use changes, such as deforestation, peatland drainage, or mangrove conversion.

“By combining these methods, we can generate comprehensive and accurate estimates of carbon emissions from both land-use changes and long-term degradation processes,” he noted.

Peatland swamps are formed when tropical forest trees grow in waterlogged soil. When leaves and other tree debris fall off, they decompose slowly because of the wet ground.

Therefore, peatlands are known to be strong carbon sponges, storing huge amounts of carbon in the form of accumulated dead plant matter.

But peatlands have declined dramatically in the past few decades due to logging, draining and burning to pave the way for palm oil plantations or pulp and paper production in the region.

“Our study confirms that the palm oil industry has played a significant role in peatland deforestation in Southeast Asia, particularly in Indonesia and Malaysia,” Lupascu said, adding that “between 2001 and 2022, approximately 1.36 million hectares (Mha) of peat swamp forests were converted to oil palm plantations, representing about 74% of the total deforested peatland area.”

Meanwhile, wetland clearance for pulp and paper production, mainly in Indonesia, has over the past two decades created huge air pollution problems in the region, often referred to as a haze, that has triggered health alerts in Singapore and Malaysia in particular.

Challenges of restoration

In 2022, ERI researchers Augusti Randi and Dr Lahiru Wijedasa swam through black river waters — streams in peatland areas that are rich in decaying plant matter that stain the water dark brown — and walked through muddy swamps in Sumatra, Indonesia, to study the diversity of peatland plants and their capacity to absorb carbon.

“If you want to restore the peat swamp, you first need to know what the plants are,” said Wijedasa, the team leader at the time.

These can then be replanted where the habitat has been destroyed, though the researchers note it can take time for regenerated forests to mature – up to 20 years for mangroves – and achieve maximum carbon accumulation, the paper notes.

“Restoration involves replicating ecological conditions that have developed over centuries,” according to Lupascu.

Lupascu pointed to the challenge of conveying research findings to government policy planners and community groups to convince them of the need to preserve mangroves and peatlands.

He said the researchers engage with policymakers through the Association of Southeast Asian Nations (ASEAN) climate strategies and Nationally Determined Contributions (NDCs) — action plans by each country on how they intend to reduce carbon emissions under the Paris Climate Change Agreement.

They also collaborate with development banks and funding bodies to integrate wetland protection into sustainable finance and carbon credit mechanisms such as carbon credit schemes.

The researchers take part in public awareness campaigns that highlight the cost-benefit analysis of conservation over restoration.

The economics of conservation

Lupascu added it was important to engage with local communities “by promoting incentives such as Payments for Ecosystem Services (PES), ensuring that conservation delivers social and economic benefits”.

PES are incentive payments to farmers or landowners who manage their land or watersheds in a way that provides ecological or conservation benefits.

In recent years, policymakers in ASEAN countries have encouraged ecotourism, in mangrove areas in particular, to provide an economic incentive to local communities to conserve and protect these untouched habitats.

Lupascu believes that if properly managed, this could bring income to local communities. It will also improve public awareness and provide education opportunities, as tourists visiting the mangroves and peatlands can learn to appreciate the importance of preserving the habitats.

However, he warns that “building roads, lodges, and other tourism facilities can disrupt ecosystems, potentially leading to unintended degradation”.

He said the carbon footprints of tourism, such as increased travel to ecotourism sites, could also reult in higher emissions, partially offsetting conservation benefits.

Wijedasa, who now works for environmental consultancy firm ConservationLinks in Singapore, noted, however, that conservation is not easy and no amount of funding for conservation can replace income generated by large plantations and small-scale farming.

The “only thing that’s going to ever generate the money to do that is the carbon market,” he was quoted recently by the Singapore Straits Times newspaper as saying.

But the researchers also acknowledge that generating carbon credits from conserving peatland or “putting a price on avoided emissions is tricky”.