The volunteers risking their lives to defuse Indonesia's wildfire 'carbon bombs' — Fahrin Ramadhianto has been fighting Borneo's wildfires for a month – and noticing the impacts on his body.
The sky grows heavy in Borneo, though not with 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.
Down on the ground, smoke steams from the soil.
"It hits your nose straight away, your eyes burn – that's more or less what it's like," he says. "People say these fires are extraordinary because of the flames and the smoke. And they're right."
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.
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.
Underground and out of sight, giant subterranean peat fires continue to smoulder, choking the air with poisonous fumes.
"Once a fire becomes uncontrolled, it harms many people. Not just humans, but also animals and plants," Sujatmoko says. "If underground fire spreads and can no longer be controlled, the losses are enormous."
Fires have torched some 200,000 hectares across Indonesian Borneo since early July
Indonesia is in the throes of a wildfire catastrophe.
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.
This 4.5-million-hectare swathe of forest and swamp, under normal conditions, serves as a valuable reservoir for ancient 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".
"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).