GlobalWarming & ClimateChange News Desk – Fires are burning underground across Indonesia as El Niño strengthens
Thick smoke blankets parts of Indonesia as hundreds of fire detections, shown in red, spread across the landscape. Credit: NASA Earth Observatory
Indonesia’s peatlands are drying out as El Niño strengthens, allowing fires to smolder underground and produce enormous amounts of hazardous smoke.
Today’s Image of the Day from NASA Earth Observatory features fires burning across Indonesia as an intensifying El Niño deepens drought across the region.
NASA’s Aqua satellite captured the image on September 1, 2026, as Indonesia entered the early weeks of its annual fire season.
Red dots on the accompanying map mark locations where the MODIS instrument detected unusually high temperatures associated with active fires.
Fires can burn beneath the surface
Some of Indonesia’s most difficult fires occur in peatlands, wetlands where partially decomposed plant material has accumulated in thick layers over thousands of years.
Under normal wet conditions, peat resists burning. But prolonged droughtcan dry the soil enough for fire to penetrate below the surface and begin smoldering underground.
Once that happens, the flames visible above ground tell only part of the story.
Peat fires can creep through buried organic material for long periods, producing enormous quantities of smoke while proving exceptionally difficult to extinguish.
They are also unusually polluting. Research suggests tropical peat fires can produce roughly three times as much fine particulate matter as other tropical forest fires, along with substantially greater amounts of several other pollutants.
Indonesia holds vast peatlands
Indonesia contains about 36 percent of the world’s tropical peatlands, making the country particularly vulnerable when unusually dry weather arrives.
Drainage has increased that vulnerability in some areas. Beginning decades ago, canals were constructed through peat swamps to drain land for agriculture and plantations.
Lowering the water table exposed more peat to drying and increased the likelihood that fires could move underground.
After Indonesia’s devastating 2015 fire season, efforts expanded to restore wetlands, block some drainage canals, improve firefighting, and prevent accidental ignitions.
The extreme conditions of 2026 are putting those measures to a major test.
El Niño is intensifying the drought
El Niño often suppresses rainfall across Indonesia, and the climate pattern was strengthening in August 2026.
A positive Indian Ocean Dipole was occurring at the same time, adding to conditions that can favor unusually dry weather.
About 90 percent of Indonesia received little or no rainfall in early August, according to the country’s meteorological agency.
That dryness matters in peat-rich areas of Kalimantan, Sumatra, and Papua. During wetter years, underground peat deposits generally contain too much moisture for fire to spread easily. During severe drought, that protection can disappear.
Robert Field, a researcher at Columbia University who studies fire weather, said fire activity was already climbing sharply and showing similarities to 2015.
That year became one of Indonesia’s most destructive modern fire seasons. After more than three months of burning, the fires had released an estimated 1.75 billion tons of greenhouse gas equivalents.
By September 2, the 2026 fires had already produced roughly one-tenth of that amount after about a month of burning.
Satellites track thousands of hotspots
Indonesia relies partly on observations from NASA and NOAA satellites to follow fires as they develop.
The country’s SiPongi fire-monitoring system counted 946 hotspots on August 31 using observations from MODIS and VIIRS instruments.
But satellites do not see every fire. Dense smoke and clouds can obscure the surface, while flames beneath forest canopies can escape detection.
Underground peat fires pose an even greater challenge. During the worst smoke outbreaks, satellite instruments can actually detect fewer fires because their view of the ground becomes blocked.
Researchers are therefore developing methods that use shortwave infrared observations from Landsat and Sentinel-2 satellites to identify more fires hidden beneath vegetation.
Smoke is already disrupting daily life
For communities across Indonesia and neighboring countries, the consequences are becoming increasingly visible.
Officials have warned of hazardous smoke exposure across large areas. Some schools have moved classes online, national parks have closed, and thick smoke has delayed flights.
The fires could continue for weeks. Underground peat fires can persist until sustained rainfall raises moisture levels enough to finally stop them, and Indonesia’s wetter season does not typically return until October or November.
The unfolding fire season will reveal whether restoration and prevention efforts introduced since 2015 can withstand another period of extreme drought.
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