Indonesia's Triple Whammy: El Niño, Fossil Fuels, and Deforestation Converge to Burn 3 Million Hectares

World Weather Attribution scientists decompose Indonesia's worst fires in a decade into three distinct drivers — each quantified, each compounding the others, none sufficient alone.

An international team from World Weather Attribution has published the most granular decomposition yet of Indonesia's 2026 fire season, isolating the contribution of three forces that together created the worst blazes in at least a decade. The fires have burned 2.88 million hectares — 19 times the size of Greater London — and are on track to surpass the century record of 2.6 million hectares set in 2015.

The scientists analyzed conditions across Java, Kalimantan, and Sumatra during the August-to-October peak fire season. Global heating — driven primarily by burning oil, gas, and coal — raised temperatures by 1.6°C over this three-month window, drying land and vegetation. El Niño, on course to break all records, layered an additional 0.3°C on top and slashed rainfall by roughly 50%. The combined effect: hot, dry air conditions were made three times more likely by climate change and five times more likely by El Niño. The third driver is structural. Decades of logging, agroforestry expansion, and peatland drainage have transformed Indonesian landscapes into a tinderbox. Pramudhian Firdaus, a meteorologist at Melbourne University who also works with Indonesia's meteorological service, put it plainly: the landscape has changed dramatically over 30 years, with extensive drainage and deforestation creating extreme vulnerability to ignition. Fires continue to burn because El Niño has delayed the rainy season by 20 to 30 days, according to Indonesia's BMKG. The downstream consequences are severe and spreading: at least 400,000 respiratory infections have been reported, including 180,000 among children, according to the health ministry. Toxic haze has reached Singapore, Malaysia, and the Philippines. The political reverberations are mounting. Protesters in Jakarta are demanding the government declare the fires a national emergency. Meanwhile, the fires and global drier conditions are contributing to an unusually large rise in predicted CO2 emissions for 2027 — even as fossil fuel emissions have dipped slightly due to supply disruptions from US-Israeli attacks on Iran. Professor Friederike Otto of Imperial College London framed the policy imperative: fire weather during El Niño years will become increasingly severe as warming continues. Without transitioning away from fossil fuels and strengthening land-management protections, worse seasons are guaranteed. The Red Cross Red Crescent Climate Centre noted that El Niño conditions are highly predictable, meaning proactive, preventive action is feasible — the question is whether it will be taken. The 2026 fire season is not an anomaly but a stress test of compounding risks. Each driver — atmospheric warming, cyclical climate oscillation, and land degradation — is independently worsening. Their interaction is multiplicative, not additive, and the costs are borne overwhelmingly by populations with the least capacity to absorb them.