Peatland Fires Burn on the Surface and Underground as Drought Grips Indonesia

Indonesia is battling a severe drought and fires that are burning both on the surface and underground in the country's peatlands, NASA's Earth Observatory reported, based on an image captured by the MODIS instrument on its Aqua satellite on September 1, 2026.

Peatland fires burn in dried wetland soils and are slow-burning, highly polluting and difficult to extinguish because they smoulder at low temperatures and often burn underground through deep peat deposits. By one estimate, peat fires generate three times more fine particulate matter than other tropical forest fires, five times more sulfur dioxide, three times more organic carbon and twice as much methane and carbon monoxide. Indonesia holds about 36% of the world's tropical peatlands.

A strong El Niño, present and strengthening as of August according to NOAA, combined with a positive phase of the Indian Ocean Dipole, has sharply reduced rainfall in Indonesia — conditions similar to the extreme fire years of 1997 and 2015. About 90% of the country received little to no rainfall in early August, according to the Indonesian meteorological agency. Robert Field, a Columbia University researcher who developed the Global Fire Weather Database, said Indonesia is only about three weeks into its fire season but fire activity is tracking sharply upward, similar to 2015.

In 2015, after burning for more than three months, Indonesia's fires released 1.75 billion tons of greenhouse gas equivalents — more than Japan emits in a year. As of September 2, 2026, after about a month of burning, this year's fires had released roughly 10% as much. Field said surface fires are less of a concern, but underground peat fires "just won't stop" and will keep burning until rains arrive in October or November.

Indonesia's Ministry of Forestry tallied 946 hotspots on August 31 using its SiPongi monitoring platform, though satellites can struggle to detect fires through thick smoke, clouds or underground peat — Mark Cochrane, an ecologist at the University of Maryland Center for Environmental Science, said the worst smoke events can paradoxically be the hardest to observe from space. The smoke has already disrupted daily life: officials have warned of hazardous exposure, some schools have shifted to remote learning, nine national parks have closed and several flights have been delayed.