Indonesia's latest wildfire crisis is not only a story of flames racing across dry land. It is also a story of what lies beneath the surface. In central Kalimantan, BBC correspondent Liza Tambunan is examining peat, the waterlogged organic soil that can smoulder for weeks or months once it dries out, helping explain why this year's fires are proving so destructive and so hard to control.
What Peat Really Is
Peat is formed over thousands of years from partially decomposed plant material in wetland environments. Under natural conditions, it remains saturated with water and acts as a vast carbon store. But when peatlands are drained for agriculture, logging, or development, the soil dries, becomes highly flammable, and can ignite deep below ground. Unlike ordinary vegetation fires, peat fires do not simply burn across the surface. They creep through the soil, often invisible from above, making them exceptionally difficult for firefighters to locate and extinguish.
That is why Indonesia's peatlands are so central to the country's recurring haze crisis. Once ignited, peat can continue burning even after surface rain has fallen, because the fire feeds on the carbon-rich layers underground. The result is a persistent source of smoke that can blanket entire provinces and drift across borders, disrupting transport, schools, business activity, and daily life. The health impact is severe, particularly for children, the elderly, and people with respiratory conditions.
A Regional Climate Threat
Indonesia's wildfire season is not just a domestic emergency; it is a regional diplomatic issue. Smoke from peat and forest fires has repeatedly spread across Southeast Asia, affecting Malaysia, Singapore, and parts of Thailand and Brunei. That cross-border fallout has long made haze a sensitive subject in regional forums, where governments are expected to cooperate on prevention, monitoring, and emergency response. Yet the underlying problem remains stubborn: land clearing, drainage, and drought conditions continue to create the perfect conditions for fire.
This year's fires are especially alarming because they are unfolding against a backdrop of hotter temperatures and prolonged dry spells in some areas, conditions that make peatlands even more vulnerable. Climate change is not the sole cause, but it is amplifying the risk. When rainfall patterns shift and soils dry out faster, the margin for error narrows dramatically. A single spark, whether from land clearing or accidental ignition, can trigger a fire that is nearly impossible to contain.
Why Control Is So Hard
Fire crews face a unique challenge in peat terrain. Watering the surface is often not enough, because the fire can continue to burn below ground. Effective suppression requires saturating the soil deeply, sometimes with heavy equipment and sustained water access that remote areas do not always have. In central Kalimantan, where access can be limited and terrain difficult, that logistical burden becomes even greater.
The scale of the problem also reflects a broader policy failure. Indonesia has made efforts in recent years to reduce peat drainage and improve fire prevention, but enforcement is uneven and the economic incentives to clear land remain powerful. Plantation expansion, smallholder burning, and weak oversight can all contribute to the ignition risk. Once the dry season arrives, the consequences can escalate quickly.
The BBC's reporting from central Kalimantan underscores a basic but crucial point: peat fires are bad not only because they burn, but because they keep burning. They turn a seasonal hazard into a prolonged environmental and public health emergency. They release vast amounts of stored carbon, worsening the climate burden. And they expose the limits of firefighting in landscapes that have been altered by years of drainage and land conversion.
For Indonesia, the challenge is immediate: stop the fires, protect communities, and prevent the smoke from spreading further. For the wider region, the lesson is broader still. Peatlands are not just wetlands. They are climate infrastructure, public health buffers, and diplomatic flashpoints. When they burn, the damage extends far beyond the forest floor.