What is 'blue carbon'? Southeast Asia's net zero answer faces setbacks

From Bali to Phuket, Southeast Asia's beaches have always captured the imagination of tourists. But rarely has anybody recognised another potential of its vast coastline - the ability of its rich marine life to achieve carbon neutrality.

The ocean system comprising tiny phytoplanktons to mangrove belts and sea grasses can store up to five times more carbon than tropical forests, but its vast natural potential is being rapidly depleted, according to Siti Maryam Yaakub, senior director at Singapore-based International Blue Carbon Institute.

So-called blue carbon is known by scientists as carbon stored in ocean systems, and Southeast Asia has one of the largest such sources, but the region is also experiencing massive losses of this potential due to human activity such as aquaculture.

Do you have questions about the biggest topics and trends from around the world? Get the answers with SCMP Knowledge, our new platform of curated content with explainers, FAQs, analyses and infographics brought to you by our award-winning team.

Within Southeast Asia, the two dominant blue carbon ecosystems are mangroves and seagrass habitats. Mangroves are essentially forests that grow in the interface between the land and the sea, while seagrass are underwater plants that thrive in brackish and shallow water.

The region had been lax in preserving its blue carbon potential, Siti said.

"For example, a lot of the mangroves in Sumatra and Java [in Indonesia] are quickly being converted into shrimp farming, and there's also conversion into palm oil [cultivation]," she said.

Indonesia is home to over a third of the world's mangroves, while other parts of Asia-Pacific such as Papua New Guinea and Sunderbans between India and Bangladesh also have extensive belts.

There are also mangrove belts in the Philippines and Cambodia.

Many poverty-stricken areas also cut down mangroves to use them as firewood for cooking, while a steady erosion is also happening due to the impact of climate change, Siti said.

"With sea levels rising, you will get more of these mangroves being inundated more frequently. And you will have changes in hydrodynamics, which drives erosion and mangroves," she said.

Even prosperous nations like Singapore have lost swathes of mangroves over the years due to land reclamation for urbanisation projects, she said.

Myanmar and Indonesia are among the countries worst hit by high population growth.

The marine systems need to be protected and nurtured for their potential because they cannot only absorb carbon within the plant biomass but also in the soil sediments, Siti said.

Around 71 countries have three of the richest blue carbon sources - mangroves, seagrass and salt marshes - but only half of these nations have included coastal and marine nature based solutions in their initial nationally determined contributions, she said.

The Nationally Determined Contribution (NDC) is a climate action plan to cut emissions and adapt to climate impacts. Each party to the Paris Agreement is required to establish an NDC and update it every five years.

The Paris Agreement aims to strengthen global response to the threat of climate change by keeping global temperature rise this century well below two degrees. A UN report late last year said the world is not on track to meet the goal.

Most Southeast Asian nations also aim to achieve net zero emissions by 2050 or 2060.

The potential for blue carbon in climate mitigation was first recognised by the UN intergovernmental panel on climate change about 13 years ago, the resource has been slowly gaining recognition by countries since then.

"Blue carbon is a relatively new kid on the block," Siti said. "Whenever we hear about nature-based climate mitigation, everyone thinks of forests.

"There's still a lot of awareness that needs to be built around what are the kinds of policies that will encourage more of this more protection and restoration actions around blue carbon ecosystems," she said.

Siti said the International Blue Carbon Institute is encouraging countries to include blue carbon ecosystems in their NDC.

The institute in October organised workshops around policy and financing solutions for blue carbon with the support of the UK government and the Singapore national climate change secretariat.

While some headway has been made, there is a lot of work ahead because the true extent and condition of resources like seagrass meadows in parts of the region have yet to be validated, Siti said.

Policymakers are sometimes unsure of how these resources can be included in their climate policy goals, she said.

"So some countries are quite advanced in that sense. And other countries are still learning about their own blue carbon resources and how they can actually include it in the nationally determined contributions," Siti added.

Another climate scientist said developing blue carbon should be a priority for national governments, but it should go hand-in-hand with efforts to reduce carbon emissions from industries and other sources simultaneously.

Souparna Lahiri, senior climate and biodiversity policy adviser at the Global Forest Coalition, cautioned that benefits derived from developing such ecosystems should not be used for trading in carbon credits in world markets because it would hurt climate objectives.

"Marine ecosystems are very good carbon sequesters, and they should have traditionally been protected. But you should not seek to develop them in order to trade carbon credits that would enable industries to compensate for their emissions," he said.

"If I emit carbon now, then it stays in earth's atmosphere for at least 100 years. By developing blue carbon sources, it will reduce carbon 40 to 50 years later," Lahiri said, adding that any effort to develop marine ecosystems for their environmental impact should be a standalone activity.

This article originally appeared on the South China Morning Post (SCMP).

Copyright (c) 2024. South China Morning Post Publishers Ltd. All rights reserved.