- Published
The sky grows heavy in Borneo, though not with rain.
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sky → publish → rain
The air, amber-hued and treacle-thick, is smudged under a blanket of smog that has spilled across international borders – to Singapore, Manila, Kuala Lumpur.
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that → smudge → Singapore
Down on the ground, smoke steams from the soil.
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smoke → steam → soil
It's like tear gas, says Dwi Sujatmoko.
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Sujatmoko → say → gas
"It hits your nose straight away, your eyes burn – that's more or less what it's like," he says.
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he → hit → what
"People say these fires are extraordinary because of the flames and the smoke.
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fires → say → flames
The 35-year-old volunteer firefighter has spent more than a month enveloped in this haze, breathing toxic millennia-old microparticles of carbon as he toils against a seemingly inextinguishable fire front.
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he → spend → front
Using hand tools, carts and portable fire pumps, he and thousands of other volunteer firefighters – many of them indigenous Dayak or Banjar people – are up against an inferno that has carbonised some 200,000 hectares of forest and farmland across Indonesian Borneo since early July.
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that → use → July
Underground and out of sight, giant subterranean peat fires continue to smoulder, choking the air with poisonous fumes.
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fires → continue → fumes
"Once a fire becomes uncontrolled, it harms many people.
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it → become → people
," Sujatmoko says.
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Sujatmoko → say → ?
"If underground fire spreads and can no longer be controlled, the losses are enormous."
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losses → spread → ?
Amid a so-called "Super El Niño" that has supercharged local drought conditions, thousands of active fire hotspots are spreading and multiplying across the country, fuelling a transnational haze crisis that is the region's worst in more than a decade.
But what makes Borneo's fires particularly worrying is the fact that they are burning through one of the world's largest tropical peatland ecosystems.
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they → call → ecosystems
This 4.5-million-hectare swathe of forest and swamp, under normal conditions, serves as a valuable reservoir for ancient carbon.
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swathe → serve → carbon
When these peatlands catch fire, they risk releasing millions of tonnes of carbon dioxide, carbon monoxide and methane into the atmosphere – a "pulse" of greenhouse gas emissions that has earned them the sobriquet of "carbon bomb".
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that → catch → bomb
"Peatlands are incredibly effective carbon stores because their waterlogged conditions slow decomposition, allowing carbon to accumulate underground for thousands of years," explains Dr Nisa Novita, a peatland researcher at Indonesian conservation NGO Yayasan Konservasi Alam Nusantara (YKAN).
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Novita → slow → NGO
"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.
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carbon → mean → atmosphere
The deeper the peat, the greater the carbon stock – and in Kalimantan, we have found peat deposits that can exceed 20 metres in depth."
A peatland that deep has been known to harbour more than 6,000 tonnes of carbon – roughly equivalent to the annual CO₂ emissions of 4,800 cars – per hectare.
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peatland → find → hectare
And when it burns, says Dr Nisa, that fossilised carbon can be released into the atmosphere "very rapidly".
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carbon → burn → atmosphere
The toxic cloud
Thousands of people across South East Asia are now feeling the effects of those emissions in their eyes, chests and throats.
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Thousands → feel → eyes
Across Indonesia as well as Brunei, Malaysia, Singapore and the Philippines, air pollution indices have soared to "unhealthy" extremes - almost 75 times the World Health Organization's recommended level, in some cases – and hospital admissions have surged.
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admissions → soar → cases
Between July and August, Indonesia's Health Ministry recorded over 50,000 cases of respiratory infections linked to land and forest fires.
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Ministry → record → fires
"Everybody who's living within that pollution cloud is breathing in the products of those smouldering peat fires," says Susan Page, a professor at the University of Leicester's school of geology and the environment, who's been researching peatlands in Asia for three decades.
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who → live → decades
"They're breathing in carbon monoxide, which is toxic, and they're 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.
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which → breathe → heart
"Living in this kind of pollution cloud is extremely unhealthy."
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Living → live → cloud
Nowhere are these health impacts being felt more acutely than at the coalface of the disaster: the fire front.
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impacts → feel → disaster
Here, volunteer firefighters have been risking their lives and lungs to extinguish burning peatlands which are notoriously difficult to put out.
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which → risk → peatlands
Two volunteers in Central Kalimantan have died in recent days, reportedly after their health deteriorated from putting out fires.
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health → die → fires
Cloaked in toxic haze that can burn years off a person's lifespan, volunteers have been digging ponds, canals and borewells through bone-dry peat in a desperate attempt to keep their hoses tapped.
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hoses → cloak → attempt
Some have been driving pipes into the earth, making ad hoc irrigation systems to combat subterranean fires.
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Some → drive → fires
Others have been sleeping within a stone's throw of the frontline so they can battle the blazes through the night.
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they → sleep → night
"The worst thing here has been the smoke," says Fahrin Ramadhianto, a volunteer firefighter in South Kalimantan's Banjarbaru, one of the worst-hit areas.
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Ramadhianto → say → areas
"The smell is like decaying wood being burned – that's the characteristic smell of peat.
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that → decay → peat
And that peat contains decomposed wood and organic material from many different sources."
An unnatural imbalance
Indonesia's peatland fires are not a new phenomenon.
Experts say the crisis is rooted in decades of land-use change, dating back to the Suharto era, when vast areas of rainforest and peatland in Kalimantan were opened for logging, plantations and large-scale development projects.
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areas → contain → logging
Yet authorities have historically avoided blaming industrial actors for causing large-scale fires.
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authorities → avoid → fires
Instead, the same indigenous communities who are now engaged in firefighting operations across the island have often been accused of triggering the blazes, due to traditional farming methods that use controlled burns to clear away vegetation.
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that → engage → vegetation
Tono, a representative of the Dayak Kanayatn people of West Kalimantan, told the BBC that Dayak communities are frequently used as scapegoats, despite carrying out land clearing with extensive planning, caution and adherence to multi-generational customs.
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communities → tell → customs
Tono says these communities' traditional practices, known as uma bukit or "hill farming", are rooted in the idea of maintaining balance with nature.
But the natural balance is fast unravelling in Kalimantan, the most deforested area in Indonesia.
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balance → say → Indonesia
The region lost almost 160,000 hectares of forest area in 2025, more than one-third of the nationwide figure – much of it to make way for plantations and monocrop agriculture.
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region → lose → plantations
It is these same industrial-scale development projects that have been largely responsible for draining the area's peat swamps, which renders them significantly more fire-prone, Prof Page says.
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Page → drain → swamps
…and 13 more, not listed.
The Aporia
