Indonesia's Peat Fires Intensify Amidst Drought and El Niño

Indonesia's peat fires are increasing early in the 2026 fire season. A strengthening El Niño and severe drought are drying out wetlands. These conditions allow fires to burn underground for months.

These slow-smoldering fires are particularly destructive. They release significantly more fine particles and pollutants than typical tropical forest fires. Thick smoke from these fires can also make them difficult for satellites to detect. Peat fires produce three times more fine particulate matter than other tropical forest fires. They also release five times more sulfur dioxide, three times more organic carbon, and twice as much methane and carbon monoxide.

Indonesia contains about 36 percent of the world's tropical peatlands. During severe droughts, these normally wet landscapes can dry out and ignite. This has repeatedly led to long-lasting fires that cover large areas in smoke for weeks. Millions of people are affected by these events. The 2026 fire season is tracking sharply upward, similar to the 2015 season. Robert Field, a researcher at Columbia University, noted this trend. The strong El Niño is making the dry season drier in fire-prone regions, exacerbating burning.

In 2015, Indonesia's fires emitted 1.75 billion tons of greenhouse gas equivalents over three months. This amount exceeded Japan's annual emissions. By early September 2026, the fires had already released approximately 10 percent of the 2015 crisis's total. Indonesia also experienced severe, widespread drought in the summer of 2026. About 90 percent of the country received little to no rainfall in early August. Normally, peat deposits are too wet for underground fires. Drought allows flames to enter the peat and smolder below the surface.

Underground fires are difficult to extinguish. They continue burning until the rainy season begins in October or November. Satellite monitoring has limitations. Instruments like the Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) struggle to detect fires hidden by thick smoke or clouds. They also miss fires burning under the forest canopy or smoldering underground. Mark Cochrane, an ecologist at the University of Maryland Center for Environmental Science, stated that the worst smoke events can be the hardest to observe from space.

Decades of irrigation canal construction and peat swamp drainage contributed to Indonesia's fire vulnerability. These activities lowered water tables, making the landscape more combustible. After the 2015 fire season, efforts were made to restore wetlands and strengthen firefighting capabilities. Shi Jun Wee, a University of Maryland graduate student, noted that 2026 will be a stress test for these measures. Hazardous smoke is already disrupting daily life in Indonesia. Some schools have switched to remote learning, national parks have closed, and flights have been delayed.