Volunteers Battle Indonesia’s Peatland Wildfires as Ancient Carbon Turns Into Toxic Haze

Fire Beneath the Forest

The sky over Indonesian Borneo has turned amber and heavy, not with rain but with smoke. A thick haze has spread from burning forests and farmland across Kalimantan to Malaysia, Brunei, Singapore and the Philippines, disrupting daily life and sending people to hospitals with breathing problems.

On the ground, the danger is often hidden. Flames may appear modest on the surface while fires continue moving through dry peat beneath it. Volunteers dig into the soil, pump water into underground channels and work through the night to stop blazes that can reappear days after they seem to be extinguished.

About 200,000 hectares of forest and farmland across Indonesian Borneo have been affected since early July, according to the material provided for this report. The fires are part of a wider national crisis, with thousands of hot spots detected across Indonesia during a prolonged dry season intensified by a powerful El Niño pattern.

Dwi Sujatmoko, a 35 year old volunteer firefighter, has spent more than a month working in the smoke. He describes the air as similar to tear gas, with an immediate effect on the nose and eyes.

Once a fire becomes uncontrolled, it harms many people. Not just humans, but also animals and plants. If underground fire spreads and can no longer be controlled, the losses are enormous.

The volunteers include many Indigenous Dayak and Banjar people who know the land and its waterways. They use hand tools, portable pumps, carts, pipes and improvised wells against a fire that can travel below the surface without producing a visible flame.

Why Peat Fires Are So Difficult to Stop

Peat is made from partly decomposed plants that accumulated in waterlogged conditions over thousands of years. Because a wet peatland contains little oxygen, decomposition happens slowly. Layers of organic material build up, sometimes reaching more than 20 metres in depth in parts of Kalimantan.

That makes peatlands valuable carbon stores. Carbon absorbed by plants remains locked underground instead of returning quickly to the atmosphere. Indonesian tropical peatlands are among the most important natural carbon reserves on Earth.

The same property creates a severe fire risk when peat is drained. Plantation development usually requires canals and pumps to lower the water table. Once the ground dries, it becomes easier to ignite and can remain combustible through long periods without rain.

Dr Nisa Novita, a peatland researcher with the Indonesian conservation group Yayasan Konservasi Alam Nusantara, explains that deep peat can hold more than 6,000 tonnes of carbon per hectare. That is roughly equal to the annual carbon dioxide emissions of 4,800 cars, based on the comparison provided by the researcher.

Peatlands are incredibly effective carbon stores because their waterlogged conditions slow decomposition, allowing carbon to accumulate underground for thousands of years. But this also means they can become a carbon bomb when they are drained or burned, because that carbon can be rapidly released into the atmosphere.

When fire reaches this material, it can smoulder underground for weeks. Water poured onto the surface may fail to reach the burning layer. Firefighters must soak the ground until the peat becomes almost like porridge, while checking repeatedly for heat and smoke below.

A Carbon Bomb With Regional Consequences

Burning peat releases carbon dioxide, carbon monoxide and methane. Carbon dioxide and methane add to global warming, while carbon monoxide is poisonous at high concentrations. Fine particles produced by the fire can enter the deepest parts of the lungs and move into the bloodstream.

Susan Page, a professor at the University of Leicester who has studied Asian peatlands for three decades, says people living beneath the haze are inhaling both toxic gases and extremely small particles.

They are breathing in carbon monoxide, which is toxic, and they are breathing in the very finely divided particulate matter, which can pass through the alveoli in the lungs into the bloodstream and cause further problems elsewhere in the body, including issues with the heart.

The term carbon bomb describes the sudden release of a large store of carbon. It does not mean that every hectare of peat will release its entire carbon reserve in one event. It refers to the risk that a slowly accumulated natural store can be rapidly converted into greenhouse gases when land is dried and burned.

The fires also remove vegetation that helps keep the peat wet and stable. After a fire, exposed ground can dry faster, making later fires more likely. Repeated burning can create a cycle in which damaged land becomes increasingly difficult to restore.

Page says drained peatlands emit carbon dioxide even when they are not burning. In that sense, the flames are the most visible part of a larger problem involving drainage, land conversion and long term emissions.

The Haze Is Crossing Borders

Smoke from Indonesian fires has spread to Malaysia, Brunei, Singapore and parts of the Philippines. Air quality readings in some areas have reached unhealthy levels, with pollution reported at almost 75 times the World Health Organization’s recommended level in the most severe cases described in the supplied material.

Indonesia’s Health Ministry recorded more than 50,000 respiratory infection cases linked to land and forest fires between July and August. More than 12,000 of those cases involved children younger than five.

In Banjarbaru, one of the worst affected Indonesian cities, schools have been closed as visibility deteriorated. A teaching assistant described conditions in which people could barely see their feet. Residents have reported coughing, sore throats, runny noses, headaches and burning eyes.

In Malaysia’s Sarawak state, nearly 600 schools were closed during a period of severe pollution, affecting about 200,000 students. Singapore has prepared for worsening air quality by stockpiling N95 masks and planning to reduce outdoor activities at schools. Residents in the Philippine province of Palawan have reported a burnt smell and irritation in their eyes and throats.

The haze also disrupts transport. Smoke reduces visibility for motorists and can affect airports, shipping routes and road traffic. It creates economic costs for communities far from the original fires, while the people living closest to the flames face the greatest health risks.

Why the Fires Keep Returning

Indonesia’s peatland crisis has roots in decades of land use change. During the Suharto era, large areas of rainforest and swamp in Kalimantan were opened for logging, plantations and major development projects. Canals drained peatlands that had remained wet for centuries.

Plantation agriculture is often linked to oil palm and other crops that are grown across large, uniform areas. These projects can bring jobs and investment, yet clearing and drainage can leave the surrounding landscape vulnerable to fire. Strong winds, dry vegetation and a low water table then allow flames to spread quickly.

Indigenous communities have sometimes been blamed for fires because some traditional farming methods use controlled burning to clear small plots. Tono, a representative of the Dayak Kanayatn people in West Kalimantan, says those communities are often treated as scapegoats.

Hill farming is rooted in the idea of maintaining balance with nature. The traditional practice involves planning, caution and knowledge passed between generations.

Small controlled burns and industrial land clearing are different in scale and risk. Traditional farmers may work within narrow time windows and local rules, while large land concessions can cover thousands of hectares and alter water systems across entire peat landscapes. Investigations into the cause of each fire are still needed, yet the wider record points to a combination of land drainage, weak enforcement, dry weather and unsafe clearing practices.

Kalimantan lost almost 160,000 hectares of forest in 2025, more than one third of Indonesia’s nationwide forest loss in the figures supplied for this report. Much of the cleared land was converted for plantations and other forms of monocrop agriculture.

Firefighters Face Exhaustion and Hidden Danger

Volunteer crews are working in conditions that can damage their health even when they avoid direct contact with flames. Smoke exposure is continuous, protective equipment is limited in some areas and heat can rise suddenly from cracks in the soil.

Two volunteers in Central Kalimantan reportedly died after their health deteriorated while fighting fires. Other crews have slept close to the fire line so they can respond when the underground blaze breaks through the surface.

Water is one of the greatest challenges. Firefighters dig ponds and wells, open or repair canals and push pipes into the peat to deliver water below ground. Remote locations may be unreachable by vehicles, leaving teams dependent on small pumps and supplies carried by hand.

Sujatmoko says the crews are tired and miss their families, yet continue working because they feel responsible for protecting their communities.

We are definitely tired. We get exhausted, we miss our families, our children, our wives. But for now, all of us are putting those things aside. We are doing everything we can to help deal with this haze disaster because it is our duty.

The arrival of rain would help, but heavy rainfall does not repair a drained peatland by itself. Water levels must be restored and maintained. Canals may need to be blocked, damaged vegetation replanted and future land use monitored to prevent the ground from drying again.

Indonesia Expands Its Emergency Response

Authorities have increased both ground operations and aerial firefighting. More than 24,000 ground firefighters have been deployed on Sumatra and Borneo, although some hot spots remain inaccessible.

Officials have requested additional water bombing aircraft for areas that crews cannot reach. Indonesia has also authorized 35 foreign registered aircraft to support water bombing and aerial patrols, provided they meet national aviation safety rules.

According to data cited by Indonesian authorities, South Sumatra recorded 1,429 hot spots, West Kalimantan 1,226 and Central Kalimantan 811. East Kalimantan registered 576, while Riau recorded 503. Forestry data indicated that nearly 94,000 hectares burned in July alone.

President Prabowo Subianto visited fire affected areas in Central Kalimantan, Riau and South Sumatra. The government has promised more water bombing helicopters and oxygen supplies for firefighters. Indonesia is also deploying military and police personnel to help regional officials with public education and fire prevention.

Indonesia and Malaysia have started cloud seeding operations, dispersing salt particles into suitable clouds in an attempt to trigger rain. Malaysia has received permission to send aircraft into Indonesian airspace for cloud seeding near the shared border and has offered additional help if requested.

These measures can reduce immediate danger, yet aircraft and emergency crews cannot replace landscape management. Aerial water drops may cool a fire without reaching the deepest peat. Cloud seeding also depends on the presence of suitable clouds and cannot end the dry season.

Prevention Requires Keeping Peat Wet

The most reliable way to reduce peat fires is to prevent peat from drying. That means restoring natural water levels, blocking drainage canals, protecting remaining forests and limiting development on deep peat deposits.

Early warning systems can help communities act before a small fire spreads. Satellite monitoring identifies hot spots, while local teams can inspect the ground for heat that satellites cannot always detect through smoke or vegetation. Fire prevention training and equipment for villages can also reduce the need for dangerous emergency responses.

Accountability is another part of the response. Indonesian police have arrested 72 people suspected of starting some fires, while four companies are under investigation for allegedly using fire to clear land at low cost. Investigations must distinguish between deliberate clearing, accidental ignition and traditional practices, while also examining whether companies have maintained legal water management and fire controls.

Indigenous communities should be included in prevention plans rather than treated as automatic suspects. Their knowledge of seasonal weather, soil conditions and local waterways can support fire monitoring. At the same time, clear rules are needed for any burning in dry conditions, especially near drained peatlands.

The regional nature of the haze calls for cooperation among Indonesia, Malaysia, Brunei, Singapore and the Philippines. Smoke does not follow national borders, so information sharing, aircraft access, health alerts and coordinated emergency planning are needed when fires spread across island regions.

The Human Cost Behind the Smoke

The phrase carbon bomb captures the climate danger of Indonesia’s peat fires, yet the crisis is also immediate and personal. Children are missing school, families are breathing polluted air and volunteers are spending weeks away from home. Some firefighters have died while trying to protect communities from a disaster that began far below the surface.

The smoke is a warning of what happens when ancient wetlands are treated as empty land. Peatlands store carbon because they remain wet. When drainage and drought remove that protection, the stored material becomes fuel, the air becomes hazardous and the effects spread far beyond the original fire.

Rain may bring temporary relief to Borneo, but lasting protection will require water management, stronger oversight of land clearing, support for local firefighters and consistent attention between fire seasons. The people facing the flames now are carrying out work that cannot be solved by emergency action alone.

Key Points

• About 200,000 hectares of forest and farmland in Indonesian Borneo have been affected since early July.
• Peat can store carbon for thousands of years, yet drainage makes it highly vulnerable to underground fires.
• Smoke has spread across Indonesia, Malaysia, Brunei, Singapore and the Philippines.
• Indonesia recorded more than 50,000 fire linked respiratory infection cases between July and August.
• Volunteers are using pumps, wells, canals and pipes to fight fires beneath the soil.
• Authorities have expanded ground operations, water bombing, cloud seeding and investigations.
• Long term prevention depends on keeping peatlands wet and controlling land clearing.