What’s fueling Indonesia’s worst wildfire season in a decade?

A government bus outfitted with oxygen tanks. Fire fighters collapsing to the ground in relief at the first sign of rain. And hundreds of Indonesian students marching through the haze, some wearing gas masks, others carrying signs that read, “If we burn, you burn with us.” These are recent scenes from Indonesia’s worst wildfire season in a decade. More than 4.6 million acres have burned across the country since August, blanketing its large island regions, like Kalimantan and Sumatra, in a thick smoke that has spread to neighboring countries. Millions are breathing in this toxic haze, and the government’s data shows that more than 300,000 Indonesians have sought treatment for acute respiratory problems.  On some days, the air quality conditions are more than 13 times worse than the threshold considered unhealthy. And like in many tropical countries, buildings in Indonesia are often built to maximize air flow, rather than filter it or keep it out. “This is a public health catastrophe,” said Robert Field, a fire researcher at Columbia University. Although there are other pressing consequences of the fires, such as carbon emissions and the harm to wildlife and forest habitats, “it’s hard to think much past the air quality issues,” he said.  The fires are the latest environmental crisis inundating Indonesia. The country is not only one of the world’s most populated, but also one of its most disaster-prone. Just last year, 1,200 residents of Sumatra died during catastrophic cyclone-induced flooding and landslides. And the country’s capital city of Jakarta, which already partially sits below sea level, is sinking. As a warming climate pushes sea levels higher, the country is racing to build a new capital on higher ground. Satellite-detected fires on the island of Borneo, which is home to the five provinces in Indonesia’s Kalimantan region. NASA These disasters are all wrought from the dangerous combination of human sprawl and climate change. But it’s not yet clear how much hotter temperatures influenced the ongoing disaster. By contrast, wildfires in parts of the world that are warming faster than Indonesia — like the recent devastating outbreaks in Canada and Europe — are clearly attributable to climate change, scientists say. The primary culprits of Indonesia’s fires, however, are no mystery. A superstrong El Niño has sent Indonesia into a severe drought, drying out the peatlands found across the country. And peat, a kind of soil packed with partially decayed plant matter, is highly flammable, especially so when dried out.