Indonesian Borneo is currently facing a severe wildfire catastrophe driven by a Super El Niño and deep-seated peatland destruction, creating a transnational haze crisis that has severely impacted air quality across South East Asia. Thousands of volunteer firefighters, many belonging to indigenous Dayak or Banjar communities, are battling active blazes that have carbonised approximately 200,000 hectares of forest and farmland since early July.
The Threat of Subterranean Peat Fires
The fires burning across Borneo are uniquely dangerous because they destroy one of the world’s largest tropical peatland ecosystems. This 4.5-million-hectare swathe of forest and swamp acts as a massive reservoir for ancient carbon accumulated over thousands of years under waterlogged conditions. According to Dr Nisa Novita, a peatland researcher at the Indonesian conservation NGO Yayasan Konservasi Alam Nusantara (YKAN), these areas function as potential “carbon bombs.” When drained or burned, deep peat deposits—which can exceed 20 metres in depth in Kalimantan—release fossilised carbon into the atmosphere very rapidly.
“Peatlands are incredibly effective carbon stores because their waterlogged conditions slow decomposition, allowing carbon to accumulate underground for thousands of years,” Dr Nisa explains. Deeper peat deposits can harbour more than 6,000 tonnes of carbon per hectare, roughly equivalent to the annual CO₂ emissions of 4,800 cars. Prof Susan Page, a professor at the University of Leicester’s school of geology and the environment, notes that drained peatlands emit carbon dioxide continuously even when not actively ablaze, while drainage drastically increases overall fire susceptibility.
Did You Know? Indonesia’s tropical peatland ecosystems span 4.5 million hectares, with some peat deposits in Kalimantan exceeding 20 metres in depth and holding over 6,000 tonnes of carbon per hectare.
Transnational Haze and Public Health Impacts
The resulting smog has spilled across international borders, enveloping Singapore, Manila, and Kuala Lumpur in amber-hued, treacle-thick air. Air pollution indices across Indonesia, Brunei, Malaysia, Singapore, and the Philippines have soared to unhealthy extremes, reaching almost 75 times the World Health Organization’s recommended level, in some cases. More than 50,000 respiratory infection cases linked to forest and land fires were documented by Indonesia’s Health Ministry throughout July and August, with upwards of 12,000 involving children younger than five years old.
“Everybody who’s living within that pollution cloud is breathing in the products of those smouldering peat fires,” Prof Page says, noting that inhalation of fine particulate matter and carbon monoxide allows these toxins to cross lung alveoli into the bloodstream, triggering additional medical complications throughout the body, including cardiovascular problems. At the frontlines, volunteer firefighters face hazardous conditions daily. Dwi Sujatmoko, a 35-year-old volunteer firefighter, describes the smoke as like tear gas. Over the past few days, two volunteers in Central Kalimantan tragically lost their lives after their health supposedly failed during firefighting operations.
Expert Insight: The crisis highlights a severe environmental trade-off stemming from decades of industrial land-use change, where drainage for plantations has transformed carbon-storing peatlands into highly volatile fire risks.
Underlying Causes and Deforestation Pressures
The origins of this crisis trace back many decades to the Suharto administration, a time when massive tracts of peatland and rainforest in Kalimantan were cleared for development initiatives, plantations, and timber extraction. Deforestation has accelerated rapidly, with Kalimantan losing 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. While industrial-scale drainage for monocrop agriculture and plantations has heightened the risk of severe fires, traditional indigenous farming methods have often faced scrutiny.
Speaking to the BBC, a spokesperson for West Kalimantan’s Dayak Kanayatn population named Tono explained that local indigenous groups are frequently blamed unfairly, even though their land preparation is executed following strict caution, thorough planning, and centuries-old traditions referred to as “hill farming” or uma bukit. As firefighters like Sujatmoko and Fahrin Ramadhianto continue working through intense fatigue, water shortages, and the constant threat of subterranean reignitions, frontline teams await much-needed rainfall to suppress the crisis.
Frequently Asked Questions
What is causing the fires in Borneo?
The fires are driven by a combination of a Super El Niño supercharging local drought conditions, decades of peatland drainage for industrial plantations, and traditional land-clearing methods.
Why are peatland fires particularly dangerous?
Peatlands store ancient carbon underground for thousands of years. When drained or burned, these ecosystems act as “carbon bombs,” releasing massive amounts of carbon dioxide, carbon monoxide, and methane into the atmosphere very rapidly.
How have the fires affected public health?
Air pollution indices have reached up to 75 times WHO recommendations across South East Asia. Indonesia’s Health Ministry recorded over 50,000 respiratory infection cases between July and August, including more than 12,000 children under five.
How will regional authorities manage future Super El Niño cycles and protect vulnerable peatland ecosystems from further degradation?
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